Louisiana State University
LSU Digital Commons
LSU Historical Dissertations and Theses
Graduate School
1957
The Electron Spectra of Cesium-134 and
Barium-131.
Leon Stanley August
Louisiana State University and Agricultural & Mechanical College
Follow this and additional works at: http://digitalcommons.lsu.edu/gradschool_disstheses
Recommended Citation
August, Leon Stanley, "The Electron Spectra of Cesium-134 and Barium-131." (1957). LSU Historical Dissertations and Theses. 189.
http://digitalcommons.lsu.edu/gradschool_disstheses/189
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IT T '
- * i. -
OP J3
o i . '
134
AIID Ba
131
A D issertation
s u b m i t t e d to t h e g r a d u a te P a c u l l y o f t h e
L o u i s i a n a D t a t e U n i v e r s i t y and
- w ; r i c u l t u r a l and m e c h a n i c a l C o l l e g e
in p a r tia l fu lfillm e n t o f the
requirem ent a fo r the d ecree o f
Doctor o f Philosophy
in
The D e p a r t m e n t
of
Physics
by
Leon D t e n l e y A u g u s t
. L o u is ia n a vteto U n i v e r s i t y , 1950
T u l o n o U n i v e r s i t y , 195D
Ju n e, 1957
The author wishes to expreo3 hi a si ace re r.pprooi >
>t i on
to i r of os .-or
i 11 t h i . ,
work, rad
'OOurioh f :ir hi s constant
to
1 r c To l : o i
?.uco i ’i 0 osia'ii.to the maauet.
ior:'
interest
C • * .;u lp h f o r
his
’~ncl help
ns s i v t -
rivJiu. o i
jo -5T
i' o
rage
AOXnO
t i
o*'
T ^ c x c c ......................................................................................................................................................
V
LToI 01
lIOUnEJ........................................................................................................................
vl
LInT
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V ili
C.I. J ' l i v
1I
II.
XJiikUJ I. J l'I Oii........................
TEE IlL TLU.-EOT - ^
4 .1 l A /
1.
s.
0.
III.
Xiiill
1.
0.
/ .
IV,
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h .•'
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'J
j |
t
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t
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<
•
•
I
•
t
■
*
*
•
*
h i s t o r y a m i ' J h o i u e o i I n s t r u m e n t .................................
The Components of the I n s t r u m e n t ....................................
h ,
One L a - m e t mi d V a c u u m C h a m b e r .........................
b • The E l e c t r o n i c l o w e r s u p p l y l o r t h e
La.- n e t ..........................................................................................
c. source P r e p a r a t i o n ..................................................
d. D e t a c t o r ...........................................................................................
e.
L a g n e t i c n i p i d i t y L e a s u r e m e r t s .......................
Th e c o l 3 V T e s t s p e c t r u m ............................................................
-t J j L a ±
iUx'ti**I j.t.-T 1k j -< Oiljoj-i / -j-u.I j i i . j O n l i H
n
.
t
T
I m p o r t a n o e o f C o n v e r s i o n C o e i 1 i e i o n t s n j id
L/X - ' l at i es .....................................................................................................
L e t h o d o f b e t e r r r ; i n i n f- C o n v e r s i o n
C o e f f i c i e n t s ..........................................................................................
V e s t o f L e t ho 6 f o r O o i o r m i n i n p C o n v e r s i o n
C o e f f i c i e n t s ...............................................................................................
Previ ous -iork............................................................................................
Pr e s e n t -.ork...............................................................................................
iii
5
10
10
16
19
0:4
£8
00
09
THE Cs134 BETA-OPLCill......................................................................................
1.
£.
O
09
41
45
58
58
59
Pn^o
V.
THE COHVEHEIQII ELEGT^OH Sl’GGTHUi: OF Cs131......................
1.
Lt
63
I n t r o d u c t i o n ............................................................................
Previous tJork..................................
P re sent rtork.........................................................................................
63
64
70
J CIHJ0TEI) BIBLIOJH.J.-HY......................................................................................................
87
VITA........................................................................................................................................................
83
iv
.’A ! i l l
L I LIT 03
Table
I .
II .
Ill .
IV A.
IV B.
V.
VI .
Page
Jumrnary
ol
D ata
^-Oouvorsi.)ii
for
Jo of f 1cl eat a of
maximum ^nerrfies
of
•
56
Ba^"*^.............................................
56
D eterm in in g
Js
1 '7j4
a lc's
i3eta--ipeot r a .
»*
50
Reported Unergries o f T r a n s i t i o n s i n Cs1 ^ Iviagrnotio S p e c t r o m e t e r s ..................................................................... .
65
Reported Ene r g i e s o f T r a n s i t i o n s in
S c i n t i l l a t i o n o p e c t r o m e t e r s ...................................................................
66
Reported l o n v e r s i o n C o o f i i o i o n t s and A/L R a t i o s
f o r Cs*31............................................................................................................................
67
uummar^ of
84
Cs^*^ B a t a ......................................................................................
v
L I S T OF FIGUHE3
F ig u re
Page
1.
Grose Sect i on of Magnet and Vacuum Chamber.....................
11
2.
i i adi al F i e l d P l o t
i n Median P l a n e ................................................
13
3.
Top View of Vacuum Chamber.....................................................................
14
4.
Regulated Current
Supply...........................................................................
17
5.
T o p View of Source..............................................................................................
21
0.
Cross
25
7.
Momentum C a l i b r a t i o n Curve f or
6.
137
Cs
C
J.
Secti on of D e t e c t o r .........................................................................
Spect r omet er ..................
31
El e c t r o n Spectrum...............................................................................
32
Decay scheme f o r Cb^37.................................................................................
34
10.
Fermi P l o t
36
11.
134
1 a r t i a l Cs E l e c t r o n Speotrum.........................................................
12.
Part.U-1
13.
f o r Cs^37........................................................................................
48
fl/B"
oouroo ). . . •
50
P a r t i a l Ba^37 Gamma-Say apectrum
fl/l6"
Source)...
51
14.
P a r t i a l Ba
fl/4"
oouroe ) . . . .
52
15.
K-Convorsion Peak of
B a ^ 7 fl/4"
Souroe ) ...........................
53
16.
k-Oonversion Peak of
Ba^37
17.
Fermi P l o t
18.
Cs'1
' 31 Conversion E l e c t r o n Spectrum
Gamma-E«y npectrum
Gamma-Eay spectrum
lor
fl/lo"
Sour oe)................
Csx" 4 .......................................................................................
vi
(Source I )
54
61
72
■ F igu re
19.
20.
21.
£**^' «
2 3 .
24.
Page
Partial
(Source
O b 1 3 1
Conversion Kl e a t r o n
76
I)...
P a r t i a l Ob131 Co nve r s i o n
(souroe V) . . .
Part i a l
fSou roe
Spectrum
■
„131
8
Coaversion
h i ).
m
.Clect ron Spectrum
77
Electron
C p e o t r u m
79
08131 Conversion PJleat ron
III ).
Spectrum
* 131
P a r t i a 1 ’■
jB
Co nver s l o n E l e c t r o n
(Souroe IV). .
Bp e a t rum
P artial
(source
K and L + U Conversion Peaks of
vi i
80
Ba^*^
81
(Souroe
IV)..
32
ABBTHAOT
-v d oubl e- f oous i ng t i r o n
employing a
scintillation
and used to
study t h e
spectrum.
by s t u d i e s
This
the
that
spectrum has
a number of o t h e r workers.
priucioal
beta
forbidden
shape and had
The K / ( L + Ll)
of
found to
be 4. 5 ± 0 , 5 .
with t h e
generally
were made on t he
seen t hor ou gh l y
t he
a
st andard
conver si on
of
These
results
a cce pt ed d a t a
coefficient
mining o t h e r
shown t h a t
the
^-conversion
error.
theoretical
coefficient
The r e q u i r e d
wi t h a s c i n t i l l a t i o n
be
satisfactory
of t he
gamma-ray
797
within
as
volue o f
t he h -
was used
In d e t e r ­
v- l u e s
t he
this
were determined
the 5-conversion
in
for
e x p e r i me n t a l
The method was
kev t r a n s i t i o n s
v 1i i
in
Other workers have
intensities
spectrometer.
by d et e r mi ni ng
605 kev and
I>14 t r a n s i t i o n
transition
to
i n BqI37 was
conversi on c o e f f i ­
and ex pe r i me n t a l
agree
first-
radioisotope.
d et e rmi ni ng
coefficients.
the
i n good agreement
The t h e o r e t i c a l
for t h i s
conv er s i on
are
on t h i s
661 kev,
comparison.
for
by
511 ±20 kev.
661 kev t r a n s i t i o n
i nvol ved u s i ng t h e
investigated
showed * unique
a maximum energy o f
be
Gs^-'^ e l e c t r o n
The spectrum obt ai ned
The method employed i n
cients
s p e c t r o m e t e r was shown to
component o f
ratio
s p e c t r o me t e r
n e t e o t o r was c o n s t r u c t e d , t e s t e d ,
1 rxA
I' 3)!
e l e c t r o n s p e o t r a o f Gs
and Ba
•
The performance o f
satisfactory
oo re magnetic
shown to
coefficients
A—
conversi on
found
to
he
transition
onelliaient
(5.Q± 0. 6)
wuu
In t he
wae observed
i’ermi p l o t
with
kev f o r t h i s
the
three
only
was
highest
131
energy
evidence
were found to
confirmed
be
these
because
three
d at a
of
94,
reported
The A-conversion
and the
of
for
was performed
reported,
who
A
0.95 ± o. 15
weak,
usi ng a s p e c i a l l y
high s p e c i f i c
the
existence
of
investigation.
Al l
were observed
highest
are
energy
a scintillation
158 and 4 05 kev.
by s e v e r a l
630,
of
t he
t he
915 and
transit.ions
The two lowest
at
could
these
principal
probable m u l t i p o l a r i t i e s a r e
t hes e t r a n s i t i o n s .
ix
g i ven.
by the
The val ues
a/ l
for
There
whose e n e r g i e s
energy
not
be
low e n e r g i e s .
transitions
high energy ones were determi ned.
when p o s s i b l e
had
spectrometer.
investigators
out-off
of
a
as well as t he
o t h e r weaker t r a n s i t i o n s
aetector
The
had been
ones whose e n e r g i e s
these
activity.
This t r a n s i t i o n
i n 0s
coef1i c i e ; t s
s i o n s were v e r i f i e d
ratios
In
a b e t a - s p e u t rum
a maximum energy of
one p r e v i o u s
Previously
transitions
ar e
investigators
been p r e v i o u s l y
in
been observed with
_Iso
Those v a l u e s
spectrum confirmed
transitions
lo4G kev.
not
797 kev
seem r e l i a b l e .
relatively
electron
in only
principal
.
the
was
spectrum.
133 kev t r a n s i t i o n
reported
*"3
of
t hose of o t h e r
data g i v e s
source o f
conversi on
605 kev t r a n s i t i o n
course o f working with
The work on Ba
prepared
x 10
methods t h a t
which had
of
t he
x 10” ^ while t h a t
(£.8±0.3)
r e a s o n a b l e agreement
used d i f f e r e n t
for
iron
These conclu
o r A/fX+M)
the
conver s i on
oooflioionts
and the IC/l or h / f X+ I l )
oaoh t r a n s i t i o n
typos:
s t udi ed
in
n
Cs *
■
'
131, 132 , lul or BC + i l l .
is
ratios
one of
indicate
the
that
following
’Phe Informsti on on m u l t i p o l a r ­
ities
has been used in proposing an improved and more com­
plete
ueoey
scheme by o t h e r workers i n t h i s
have done o t h e r
experiments on B a ^ ^ .
X
l a b o r a t o r y who
CHAPTER I
In PA OD UdTIO N
The p r i n c i p a l
p ro b lem s
o o lle a tlo n
and I n t e r p r e t a t i o n
of
finds
various
tio n
In terms o f
theories
n u o leu r
a nuclear
nuclear
forces.
theory.
nucl eus
natu re
the
forces
of
objective
Is
to develop
as
a result
does
both t h e o r i s t s
an adequate
of
their
exist
Joi nt
speot rosoopy o f
studies
bota-decay.
am; l e of
in t h i s
area
The r e s e a r c h
nuclear
because
and
not
the
of
nature
satisfactory
the
exact
known.
The
experimentalists
n u c l e a r phenomena
efforts.
i n f o r ma t i o n
radiations
explana­
regarding
e x p l a n a t i o n ol
O n e a r e a of ex pe r i me n t a l
y i e l d e d much u s e f u l
and t h e i r
as e r e s u l t
is
the
a result
and compl etel y
not
are
is
A number of
between nucleons
of
p h y sio s
o b ta in ed
ex p erim en ts
unilied
the
i^ost
data
s i m p l i f y i n g assumptions
t he o r y of
ultimate
of
n u clea r
and models hove been developed
making c e r t a i n
of
of
of
investigation
©bout n u c l e i
omitted
is
that
by r a d i o a c t i v e
er e made on I s o t o p e s
r epor t ed
which has
in t h i s
subst ance
th: t
paper
of the
in
undergo
' n ex­
such an I n v e s t i g a t i o n .
Prom an experiment© 1 p o i n t
s t u dy i n g a r a d i o i s o t o p e
o b t a i n an energy
level
that
of
v 1ov, , t he o b j e c t ■
; vc
undergoes b e t a - d e c a y
diagram f o r
the
product,
is
to
nucl eus.
1
auch a diagram
reached
tron
showa a l l
by b e t a - d e c a y
transitions
plete
energy
as s i gn me nt s
lor
considerable
■the oner-ry l e v e l s
and t h e
that
level
of
o ccur between t h e s e
level
i mpor t ance
also
since
for
oan be
gamma-ray and c o n v e r s i o n
diagram must
each
that
include
these
pur poses
levels.
A com­
spin
and p a r i t y
quantities
of
elec­
are
of
comparison wi th
theory.
In obtaining
scheme
rays,
for
it
of
radioisotopes
is
two t y p e s
separately.
used
and
us ed.
spectrometer,
more
reliably
make gamna-rey
are
energy p a r t .
difficult
not
end i s
introduced
corrected
usually
into
for
spectrometer
shown t h a t
t he
ones most
inten­
scintilla-
measurements
can be
there
and
correction
employed
studying
is
ore
in
photons
of the
t he
when t h e
and when t h e measurements
which
the
higher
data
Co n s i d e r a b l e
values
corre­
suppressing
to
to
t h e photo -
an a g g u l a r
the
relative
made.
a
ki n ds
spectremeter.
results
spectrum
the
gamma-ray
intensity
electrons
intensity
are
made wi t h
spectrometer
not
these
s c i n t i H a t i on
has
The n e c e s s a r y
st udy
the
correlation
of t h e
to
studies,
measurements by
ejected
This
necessary
and gamma—
different
from a r a d i a t o r ,
between t h e
electrons
decay
the
a magneti c
Intensity
a complete
Of
electron
t h e magne t i c
lower energy p a r t
be
whi l e
for
both
more r e l i a b l y
made with
ejected
them.
these
llxperi ence
1 ion
While
for
the magneti c
measurements
produce
emit
radiation
of
sity
lation
that
data
and u s u a l l y
spectrometer
electrons
required
co nv e ni e n t
instruments
generally
the
is
quite
error
effect
extend
can
is
over a
3
wide range of energy.
most
The e f f e c t
of t h i s
correlation is
f o r photon ener gi es below 0.6 M e v .
important
Conversion e l e c t r o n and b e t a - s p e c t r a are more r e l i ­
ably
studied with a magnetic spectrometer because the
imental
data
ore usual ly
scintillation
the g r e a t e r
cl eaner than t h a t
spect rometer.
obtained
i'or conversion e l e c t r o n
r e s o l u t i o n of the magnetic
exper­
with a
studies
spectrometer i s
of
consi derabl e advantage.
In comparing these two i n s t r u n e u t s , mention should
also
be made of the g r e a t e r e f f i c i e n c y
scintillation
spect romet er.
if'rom a comparison o± these
that
beta and gamma-ray s t u d i e s
ments are used t o g e t h e r
The s p e c i f i c
cerned with the
t r o me t e r ,
of d e t e c t i o n of the
instruments i t
are best made i f
so as to
is
the
clear
instru­
complement each o t h e r .
r esearch reported
i n t h i s paper i s
c o ns t r u c t i o n and t e s t i n g of a magnetic
testing
con­
spec­
a somewhat d i f f e r e n t method of determining
conversion c o e f f i c i e n t s ,
meter and the method to
and the a p p l i c a t i o n of the
spectro­
the study of the decays of Cs-^4 end
Ba1B1.
The magnetic spectrometer b u i l t
the
electron
s pect r a of
was st udi ed to t e s t
was used to
Os-^’4 , and
the performance of the
Gesium 134 was st udi ed to t e s t
ing conversion c o e f f i c i e n t s .
Cesium 137
i nst rument .
the method used
In the
in determi n­
wor’: on Cs^?4 a b e t a -
spectrum was found which had not been previ ousl y
As a r e s u l t
of fi ndi ng t h i s
study
report ed.
beta-spectrum f u r t h e r work i s
pl anned on
at
in t h i s
per haps b e s t
this
paper i s
this
laboratory,
r egar ded
decay of
was s t u d i e d
primarily
i n o r d e r to
with
determine
conv er s i on l i n e s .
scintillation
spectrometer,
st op
in
these
transitions
check. 011 t h e
cient
of
t he
intensities
relative
intensities,
that
comparison,
assi gnment s
were cl so
scheme of
j3b ^
gamma-ray
studies
a.
^
rt.
is
of
the
for
a
t he v a r i o u s
t he
ser ve
on t h i s
transitions
at
levels
this
be p u b l i s h e d .
in
i n f o r ma t i o n on
can y i e l d
deta.i 1s of
isotope
to
as a
conv er s i on c o e f f i ­
with o t h e r
assi gnment s
of
to
thu
in
v l ue s
for
Is-1
- *' .
cornp 1oto
bo i ng done by Campbell"** vino made
Campbell,
coef­
quantities multipolarity
conjunction
The working out
as p o s s i b l e
from t he
were made f o r a number of
and p a r i t i e s
661 kev t r a n s i t i o n
t he 1- o on vc r s i on
determined
reached
Ba l*Jl t t h e s e m u l t i p o l a r i t y
sp i 11b
with a
The K/L and k / ( L + L.) r a t i o s
from t h e s e
i'/hen used i n
of
from t he c o r ­
were determined
and u si tig t he
in
conclusions
measurements•
from t he
s p e c t r o me t e r
were determined as a c c u r a t e l y
number of t r a n s i t i o n s
the
as an i n i t i a l
t he magnetic
From t h e s e
Ba^-37 as a s t a n d a r d
ficients
of
work chscusGed
spectrum r e s u l t i n g
r esponding gamma-ray i n t e n s i t i e s
in
the
proposed program.
Tho convoreion e l e c t r o n
the
and
the
laboratory.
docay
CHATTY
II
TH3 I IhiTiiUUlhJT AIID IT J P l i h J h i J E
1.
are
History
t he
and Qholoe o f
The two p r i n c i p a l
k i n d s o f magnetlo
flat
helical
t ype
and
tho e l e c t r o n s
that
angles
field,
trons
to
the
that
field.
are
of
spectrometer.
free.
that
portional
to
whereas
t ype
of
the
in the
equipment
ticking t he
the
current
is
that
with g r e a t e r p r e c i s i o n
that
t ype
rigidity.
than
whose e n e r g i e s
I r on
free
to
current
iron
a coil
of
field
is
of
the
pro­
such
readily
strength.
rigidity
emitting
flat
usu­
be s t r i c t l y
and magnetic
sources
the
has
be measured
of
baffles.
type
free
elec­
o f a long
The advantage
can
can the
current
that
right
with t h e
pl aced
1’ o h e l i c a l
i n s t r u me n t
at
appropriate
similar
t ype
t hose
consists
can be t ake n to
the
connect!ug tho
o t h e r means.
placed
is
determi ned by c a l i b r a t i o n wi th
electrons
helical
spectrometer
chamber a r e
t h e magnetic
an arrangement
flat
d e t e c t e d movo approxi matel y
The c o n s t r u c t i o n of
advantage
constant
In t he
vacuum chamber around which i s
Inside
iron
type.
s p e o t r o me t e r s
d e t e c t e d make much s m a l l e r a n g l e s
The o t h e r n e c e s s a r y
ally
the
are
The h e l i c a l
cylindrical
wi r e.
Instrument:
The
is
conver si on
have been a c c u r a t e l y measured by
c o n s t r u c t i o n has t he
t h e power consumption o f
t he
5
i n s t r u me n t
d i s adv ant ag e
is
greater
t han
6
that
for
an i r o n
r e qui r ement s
plied
i n s t r u me n t
f o r an i r o n
by a r e l a t i v e l y
i nexpe ns i ve
type was t h e
gener&tor
sively
to
set
with
was t h a t
that
was not
space.
in actual
The
physical
was a v a i l a b l e
i r o n p ol e p i e c e s
used
in
the
i ns t r ument
to
t ypos
are
spectrometer
the
fact
greater,
better,
or
reasons
build
two t y p e s t h a t
mi s s i on o r
is
and
size.
spectrometer
is
set.
helical
The most
iron
A mot orexclu­
funds were not
helical
helical
supply.
could be used
place
sup­
available
consideration
t ype
is
rather
conveni ent
space
suoh an i ns t r u me n t
type.
The f l a t
was
type
more compact and could be r e a d i l y
space a v a i l a b l e .
i'or t he
this
that
i r on f r e e
f o r the
with
of
free
.'mother i mpor t ant
in which t o
deemed i n s u f f i c i e n t
ever,
iron
b u i l d i n g t he
available
The power
power
g r e a t e r power consumption.
suoh a u n i t .
of
that
not
such an i n s t r u m e n t ,
pur chase
large
electronic
by the
for
size.
oan be a d e q u a t e l y
s u p p l i e d by a do mo t o r - s o n e r a t o r
Tho main reason
free
equivalent
i n s t r u me n t
The g r e a t e r power r e q u i r e d
usually
of
indicated,
was l i m i t e d
constructed
could
was
type
the
does
for
s i mp l e r
for the
a flat,
t he
t he
t he
and e a s i e r
compare
type of
one of two p o s s i b l e
have been b u i l t ,
not
choice of
wit h i r o n pole p i e c e s .
r e s o l u t i o n with t h e
that
to
the
100°
to
f av or a b l y
type t h a t
the
d o u b l e - f o e i s i n g magnetic
Of the
flat,
magnetic
construct.
in terms
was chosen.
same r e s o l u t i o n t he
same t r a n s m i s s i o n
flat
How­
of t r a n s ­
Because
transmission
resolution
is
s p e c t r o me t e r was
is
built
instead, o f t h e
100° t y p e .
ence between t h e two typeB i s
the
180°
t ype t h e
distribution
and t h e
i r o n pol e
where t h e
olectrons are
source.
In t h i s
.just one d i r e c t i o n .
pieces
are
occurs a t
shaped,
it
to the
field
is
is
not
In
field
uni f or m,
100° away from t h e
is
f oo us i ng i n
uni f or m,
pole
and f o c u s i n g
so ur ce.
t yp e o f
spectro­
from work, on the b e t a t r o n and o t h e r
c l e s performed o s c i l l a t i o n s
that
about
the a c c e l e r a t e d
any mode of o s c i l l a t i o n
could
parti­
an e q u i l i b r i u m o r b i t .
component and a h o r i z o n t a l
periods of these
two modes
p o i n t s along
equilibrium o r b i t
t he
t he
d o u b l e - f o c u s i n g t ype t he
accelerators
One can imagine t h a t
there
development o f t h i s
was r e a l i z e d
kinds o f p a r t i c l e
a vertical
a focus
i n s t r u me n t
In t he
the
electrons tr a v e l
to
differ­
distribution.
pieces are p a r a l l e l ,
focused
of
field
Tf(2)^ radianB from t h e
Prior
meter,
t he
brought
t ype
The onl y e s s e n t i a l
is
composed of
component.
be made e q u a l ,
there
If
at
t he
certain
would be nodes,
i.
e . , a d o u b l e - f o c u s i n g o f t h e p a r t i c l e s a t t hose p o i n t s .
g
Siogbahn and dvertholm
achi eved t h i s c o n d i t i o n i n a magnetic
s p e c t r o m e t e r by shapi ng t h e
The r a d i a l
plane
dependence o f t h e
f o r t h e i r magnet
i r o n pole p i e c e s
field
strength
of t h e i r magnet.
in
the median
is
B * B0 ( r 0 / r ) l
(1)
2
k . Siegbahn and N.
(1946); IT. Svartholm and k.
A33, No. 21 (1946).
Svartholm, Nature 1 57. 8 72
8iegbahn, ^ r k . MatT iCstr. Fys.
8
where r Q i s
the
r a d i u s of t h e
equilibrium o r b i t
r a d i a l distance
where t h e
strength
is
B0t
and r
field
strength
is
li.
The l o c a t i o n of
tho p oi nt
b
r
* r Q, t he
b0 [ i
If
3
s e r i e s obt ai ned
e r i n g t h e more g e n e r a l
Thei r a n a l y s i s
and t h a t
trary.
The value of p
defining
resolution
is
will
to use.
To out a i n p
of
diver gence.
0 50
T,
(lc
J 47).
for p
Doc. AQ5.
is
iiedgran. T.
TOO (18 50).
somewhat a r b i ­
is
the best
for P
-
shape
6r / Q , the
the v e r t i c a l divergence of
resolution
The d i f f e r e n t
p i ec es
in
if
Dennison, Thy s.
biegbshn and U.
the
independent
of f l are
valuer
sli.tntly
= ^/O oiegbahn e_t a l . ^
o h u l l and D.
be - l / 2 ,
an angul ar d i s p l a c e -
tho pole p i e c e s must be shaped so t h a t
3
(2)
They begin by co ns i d ­
Tor example,
obt ai ned by shaping the i n l c
ways.
.
a somewhat more g e n e r a l
determine what
value l/Q makes the
the h o r i z o n t a l
...]
f o r double-focusirig ot must
The value
independent
beam, while the
equat i on i s
equati on
radians.
baffle
for t h i s
can
made around
3/a
d oubl e- f ocus i ng occurs a f t e r
Tf ( z ) -
of
+
the problem.
shows t h a t
mont of
of
)
have shown t h a t
can be made to
the median piano
a Taylor expansion i s
- 1 /2 ( r ; o r°
Shu l l and -Dennison
approach
1.
t he
which the
field
be seen from Titrure
is
at
different
have shown t h a t
a vertical
*iov.
71_,
^vartholm,
cross
081;
IT: .
Iroc.
Thys.
9
s e c t i o n o f t h e magnet
is
taken,
t he
i n t e r s e c t i o n with the
pole p i e c e s gi ves two par abol ae whose v e r t i o e e
center
of t h e map-net.
z ■ c • ( r ) 8 , where
and c i s
at
the
Tho equat i on of e i t h e r p ar abol a
z is
a cons t ant
lie
the d i s t a n c e
that
from t h e median pltmo ,
determined b y
is
is
the a i r
cap s i z e
desi r e d .
starting
if
r
a particle
■ r +dr
is
at
emit ted
( 3) ,
h hu l l and Dennison show t h a t
from t he
source a t
the
p oi nt
z * dz,
and makes an angle ^ i n the median plane and an
angle y* which i s
plane,
wi th £q.
i n a plane
then t he p a r t i c l e
t he p oi nt
p e r p e n d i c u l a r to
will
strike
t ne median
t he plane I? = f f (2)^
given b37 the f ol l owi ng e q u a t i o n s :
r * = r Q - dr +
(E ~
3‘ .
drE +
<
■
« * ~ 51 dz2 +
3r0
(4)
z*
i'rom 3q.
-
-
dz + S—
J^L dr dz •+
■
3 r0
(4 ) and n o t i n g
that
dr
d (.Br )
the
the
r Q/ uf .
dispersion
4r
hr
(6)
f ol l owi ng approximate e x pr e s s i on can be derived
momentum r e s o l u t i o n ,
-<, a t
b
is
the
f o r the
h a l f maximum:
8
■
(£-------(
—16
H =f —=
■+
■ —w
- — +• —
7 )
6r0
8r 0
£4
where
(5 )
3
^
source width and w the
(16ytf — 6 )
£4
d e t e c t o r width.
10
2.
The C o m p o n e n t s o f
a.
thc_ I n s t r u m e n t :
The M a g n e t a nd Vacuum Cham be r
In Pig.
The magnet
is
1 is
shown a cross
secti on
symmetric about a v e r t i c a l axi s
cent ers of
C and P£ l or the v e r t i c a l
The iron yoke consisting: of
soft
i r on .
of t h i s
of themar-not.
cross
the
secti on shown
, C and
i s made of
The exact physical and m e t a l l u r g i c a l p r o p e r t i e s
i r on are not known since i t
from a l o c a l concern.
was purchased as scrap
The h y s t e r e s i s of t h i s
that
for a current of 200 rrta the dif f er ence
sity
on the two sides of the h y s t e r e s i s
The maximum current
various p a r t s
the
through
i ron i s
in f i e l d
such
inten­
loop i s about 1%.
sent through the magnet was 075 ma.
shown in Pig.
The
1 were machined i n tho shop of
College of Chemistry and Physios.*
The shaping of the pole pieces to
uvcrtholm parabolic
facilities
at
this
the biogbahu and
cross secti on could not be done with the
l abor at or y.
>vn attempt was therefore
made to approximate the required parabola with a p a i r of
straight
lines,
so t hat
the pole pieces would be conical
the region where the focused e l ect r on s t r a v e l .
determine the s t r a i g h t
a full-scale
1, was made of the magnet.
tance of 4t" was 2".
In order to
l i n e s t h a t would most closely approx­
imate the desired parabola,
Pig.
in
Prom t h i s
The a i r
drawing,
s i mi l a r to
gap at a r a d i a l dis
information the constant
in
^cknowledgment i s made to Hr. ^Cdward Keel and h i s
a s s o c i a t e s f or t h e i r work on the items shown in Pig. 1 and
also on t ae d e t e c t o r , Pigure 6.
MEDIAN
PLANE
H
I’i g .
1
J r oas
Petition of Ivlagnet anti Vaouurr. Chamber
11
K
the
equation
for
the parabola
p a r a b o l a was t hen p l o t t e d ,
is
det ermi ned.
and t he
b est
i mat i o n was determined
graphically.
checked a n a l y t i o a l l y .
It
desired
pole
piece
b e v e l on the
4. 5
inches.
the
field
imat el y
p ol e
case
r Q and 0
might
at
that
coil.
various
radii
The r e s u l t s
r Q = 5.85 inches
gave t h e b e s t
the
value
fit
to
of 0
t he
to
at
over t h e
central
about
-
cut
a 5.2°
distance
of
pieces,
desired
as
i nch es
region
VQ and
aluminum cut
pieces.
details
r e c t a n g u l a r holes
ar e
bvartholm,
.
to
are
cut
l/4.
^rk.
o/O , a s
this
i n t he
shown t h a t
for
2 show t h a t
field
form
choice of r Q.
by p r o p e r p l a c i n g o f the
of p a r t s
in i'ig.
1,
of
the
top
and
and two concen­
The rims e r e
fit
held
together
t h e gap between t h e pol e
some of
f.
i/hile one
si nce t h e
for
£ for
These v a l u e s of
has
shown in I'ig u re
in
approx
and d e t e c t o r .
indicated
by p i e c e s o f
shown i n 1'ig.
The d a t a of 1'ig.
5.8
of
were determined by
Ovartholm
defining b a ffle
aluminum r i ms ,
The
to
data o btained.
The vacuum chamber c o n s i s t s
bottom pol e
were a l s o
a current
bo c l o s e r to
Thi s v a l u e o f r Q was e s t a b l i s h e d
tric
f or
are
md
Siegbahn1s i n s t r u m e n t ,
r 0 should be f i x e d
source,
approx
achi eve t he
wouldbenecessary
200 me t hr ough t he ma.-met c o i l
adequate
to
s ta rtin g ata ra d ia l
c o n i c a l pole p i e c e s f i = 1 / 4 .
is
line
The r e s u l t s
found t h a t
it
pieces
strengths
expect
case of
shape
straight
rfhen t he magnet was completed and assembled,
means o f a f l i p
t he
was
The d e s i r e d
Fys.
these
2,
iJb.
3.
Appropr i at e
aluminum p i e c e s ;
14,
115
(184b).
too
experim ental
I.075
CALCULATED
1.050
I.025
C
DC
D
O
I OOO
O. 9 7 5
0.950
O 925
5
7
6
RADIUS (INCHES)
Pi g.
£
Radi al
Pield
Plot
i n Median Plane
M
SOURCE
S
R
± 'ig .
3
Top
V iew
14
of
Vacuum
C h anter
15
th u s,
they
a lso
have h o le s
h o le
in
1 5/0"
out
the
in
a s the
I n them a r e
the
rem ovab le.
if
tig h t
a ch iev ed
tom s o f
th ere
d ia m eter neoprene
alum inum r i m s .
the
f l a n g e m arked 8 ,
P,
and
the d e te c to r
of
O -rin g
of
the
covered
e lim in a tes
c o il
does not
uous
5 m icro n s.
in th e
c a u s e any
w ould
sists
w ire.
space
c o il
th ick
is
v e rtica l
alum inum and
alum inum b a f f l e s
use,
the
A vacuum
t o p s and b o t ­
O - r i n g s w e r e m a de f r o m l / 8 M
grooves are
is
attach ed
R,
to
the
to
in
the
in
the
chamber
v a c u u m pump a t
a r e made by m e a n s
w elded
c o il
cut
is
in to
the o u te r
p la ced .
T h is
sh aft
pasB.
the
pressure,
(75 kev to
n o tic ea b le
a v a ila b le
the
ch a m b e r by m ea n s o f a
The r e s i d u a l p r e s s u r e
At t h i s
o f a p p ro x im a tely
T h is
in
co n n ectio n s
hove
m ain tain ed
a lin e
The
a r ecta n g le,
at
c o u p lin g to
A ll
th at
a vaouum s e a l t h r o u g h w h ic h t h e
exp erim en ts
spectrum o r
the
T hese
the
for
the
chamber
the energy
1 M ev) ,
d isto r tio n
in
in
gas
e ith er
range
sc a tter in g
a co n tin ­
spectrum .
The c r o s s - h a t c h e d
is
O -rin g s
where a r o t a t i n g
G en oo m e o h a n i a a l p u m p .
about
is
l/8 "
The n - r i n g
a t D.
a speoe
ro ta tin g
II,
for th e ir
The a lum inu m c a n ,
A vaouum i s
is
by l a r g e
The s o u r c e h o l d e r
at
arrangem ent
are
iB any n e e d
cord.
sea ls.
the fig u r e .
and 1 l / 2 "
b a ffles
t h e alum inum r im s .
rim p r o v i d e s
b a ffle,
The o n e s
in
O ne-qu arter in ch t h ic k
are a v a ila b le
is
system ,
in d ica ted
r ed ia l d ir e c tio n
The p r e s e n t
seal
b a ffle
cen tra l d efin in g
d ir ec tio n .
rea d ily
serve
sectio n
fo r the
betw een
magnet
c o il.
and G i n
T h is
c o il
P ig .
1
con­
5000 t u r n s o f #24 form var covered
w o u nd o n a s p o o l made o f
l/l6 "
alum inum .
16
The leadB to
the
ooil
tube between VQ and
ar e brought out
through a vacuum t i g h t
.
The pole p i e c e s and the aluminum rims e r e
clamped to c-ether by moans of a l a r g e
arrangement.
vertical
The b o l t
axis.
between C and
steel
nut
f i r ml y
and b o l t
runs through the magnet al ong t he
There a r e a l s o
two small
steel
, and two between C and P g.
aligning pins
The p i n s ar e
needed because the magnet can be assembled i n only one way.
The l a r g e b o l t ,
o r d e r to
b.
nut and p i n s are
keep t h i s
not
shown i n Fi g.
drawing from becoming too
The E l e c t r o n i c Power Supply f o r
The e s s e n t i a l
magnet
o o i l ar e
supply
(T-ft-F) t h a t
is
f e a t u r e s of the power supply* f o r t he
shown in Figure
4.
The unregul at ed power
pr ovi des t he main c u r r e n t
nothi ng of p a r t i c u l a r
them.
The 200 v o l t
scr een supply
on the
same c h a s s i s
as the T-rt-F.
supply with t he
rate
is
chassis.
al so
300 v o l t
The c o n t r o l
on a s e p a r a t e
for
circuit
chassis.
the
to
show about
d07Ts i s
outputs
The e n t i r e
to
shown i n d e t a i l
interest
which i s
Regul at or .
c o n t r o l t he ac output
not
and the o t h e r
mounted
The r e g u l a t e d vol t age
and 150 v o l t
a Model 1001 Sorensen A.G.
r a t e d to
confusi ng,
the Magnet
two r e g u l a t e d v o l t a g e power s u p p l i e s aro
si nce t h e r e
1 in
This
is
on a sepa­
shown i n d e t a i l
circuit
is
regulator
wi t hi n ± 0 . 0 1^ .
fed by
is
However,
*The a s s i s t a n c e of Mr. L e s l i e Edlen and Mr. G. L.
Peacock, J r . i n b u i l d i n g some of t h e e l e c t r o n i c equipment
i s g r a t e f u l l y acknowledged.
T-R -F
+ 150
4 5 0
V
400
MA
+300
200
REGULATED
REGULATED
TO
FOUR
S OT ' S
A
330 ^
TO
V
IO K
POTENTIOMETER
-AAA
4 7-A-
J lS L Q A .
MAGNET
COI L
( 4 0 0 JA. )
2.5 K
30 W
202
47 K
AAAAA
V R I50
O W
I OO K
H POT
V —
MEG
6 A N8
v R 150
VR
5651
150
IO K
10 K
H POT
\-----f\
A
■
=
£“ 6 V
S.K
ww
f
4
Kegulated Current
17
Supply
I O v-v
STD.
18
teats
indicated t h a t
a more r e a l i s t i c
l a t i o n was ±0.Q5>,
bince the
as well as d e s i r e d ,
the
p l i e d by a 6 v o l t
6AN8 must be as
tuations
in I t
f i l ament
will
fol lowi ng a c t i o n s
the
current
decreases.
and,
if
8 0 7 ' s to
which i ncl ude
t he
similar
increase;
gr i d of the
erence t ub e .
triode
pot which i s
si d e of
ooil,
to
effectively
decrease
6AIT8.
const ant
5 ma to
the 6AN8.
the
6AIJ3
This v o l t ­
control
current
i n s e r i e s with
On t h e o t h e r hand,
it.
there
will
be a
The v ol t age
that
on t he
The v ol t a ge on the
by the
5651 vol t age
ref­
can be changed
375 ma by means of the
change the gr i d
through
of the
the
compared a g a i n s t
is
held
are
increases,
t he
used to
side
therefore,
side of
from
As a r e s u l t ,
increases.
increases.
ooil
current *
some reason
the current
The c u r r e n t through t he c o i l
from approximately
the
through the pent ode,
elements t h a t
compensating a c t i o n
the t r i o d o
current
coil
causes t h e v o l t a g e on the
the
to
results
for
decreases.
p la t e voltage
c u r r e n t through the
drop acr os s Hs i s
g r i d of
If
decreases,
This reduces the
through the 807* s and a l l
them,
i n the
c o n t r o l g r i d of t he pentode
its
6AN8 was sup­
current
circuit
cirouit.
resistor,
age i n c r e a s e n a t u r a l l y
g r i d s of t he
control
this
through the c o i l
consequent l y,
regu­
as can be obt ai ned because any f l u c ­
of
rts , a 10 ohm st andard
to the
This
i nt r o du ce v a r i a t i o n s
t he
on tne
current
automobile b a t t e r y *
const ant
the
r e g u l a t o r did not perform
The r e g u l a t i o n o f the
voltage
e s t i ma t e of
lOic Hel i -
v ol t age of t h e t r i o d e
19
An I n t e r e s t i n g
m a i n t a i n t he
current
ing.
load
If
the
by about
0.01;b.
this
the
stant
This
inability
compensate
4,
t he
changes t h a t
for
external
r a t h e r are
current
t hrough
t o w i t h i n ±0.01>o f o r
degree
of
stability
f o r the work done t h i s
c.
i n the
changes
evident
coil
olrcuit
change
to
shown i n
from 5 to
has proven to
ooil
associ­
can be maint ained
a p e r i o d of
ade­
in the
some i n s t a b i l i t y
coil
that
current
t he
con­
10 mi nut es.
be more t h a n adequate
fur.
caused by source
well
nique t o
is
adequate
be d e s c r i b e d
down to
relatively
high
sion l i n e s ,
so
specific
serious
to
l a n g e r . ^ i'or more r e f i n e d
L,
M.
langer,
In the
in the
is
3ci.
of b e t a -
sources o f
study of
consequent
study of
for
similar
techniques
rtev*
study
50 kev f or
be d e s c r i b e d
consideration
i n the
The p r e p a r a t i o n t e c h ­
and the
a problem as
thickness
f a r t he
activity.
source t h i c k n e s s
source under
known.
an energy of about
The t e chni que
of
is
to
follow­
arrangement
is
not
t he
With t h e
study of b e t a - s p e c t r a
is
is
circuit
current
it
control
of
the
Oource P r e p a r a t i o n
The d i f f i c u l t y
spectra
teat
causes o f
a result
SAN8 i t s e l f .
t he
occur
o f the
of
constant
of
not
1'ig.
ooil
As a r e s u l t
are
a t e d wit h t he
the
halved,
large
c u r r e n t , but
through
ability
is
relatively
quat el y
of t h e
resistance
any
due t o
test
scattering
beta-spectra.
preprring
to
conver­
that
the
used
kind
by
r e f e r e n c e may p r o f i t a b l y
Instr.
hO,
£16
(1942).
20
bo made
to t h e
drawing
of a t y p i c a l
tion
of
t he
d i a me t e r
3.76 am.
while the
first
and a l s o
erence marks,
These
are
completed i t
the
threaded
is
it
i s desired
^fter
mi l t h i c k
is
attaching
the
from i t
that
t he
ar e
made,
screw a t
the
recommended i n
source
a piece
the
long and
rim,
rim and at
of
is
t he o t h e r two
5.
right
After the
trimmed o f f
to
cement
of the
source
tip
of
event
aluminum f o i l
rim.
0.2
Prior
is
to
cut
In a t t a c h i n g
the
r e f e r e n c e marks a r e
so t h a t
a n gl es
the
lo0°.
3/32" wide.
r e c t a n g u l a r hol e
ref­
marks.
the
section
1 1/ 8"
of
of
«Vhon t he
a rectangular
shown i n i ’l-mre
aluminum f o i l
a 4-40
t he
t he
reference
aluminum f o i l ,
is
to
t he
rides
cement.
the
as
rim i s
to
t he
rim wi th luco
used to
of t he
rotate
to
tho
to
center
to
angles
wi th a 4-40 t a p .
Two h o l e s
attacnod
aluminum f o i l
align
parallel
to
cutting
Another p a i r of
right
into
out­
Two r e f e r ­
. / e l e c t i n g one p a i r
drilled
attached
source h o l d e r .
that
are
lathe.
at
of
3.14 cm and t h e
1/ 8" t h i c k .
i n the
ar e
Prepara­
can be made wit h the
al ong a d i a me t e r .
both h o l e s
is
The rim i s
two h o l e s
5,
view
machining on a l a t h e
di a me t e r i s
can be made l a t e r
rim r.o t h a t
hol es
wi th t he
still
7
A top
Blatis.
shown i n .Figure
same di a me t e r
rim i s
r e f e r e n c e marks
is
The i n s i d e
ence marks on t he
tool
source
source begi ns
an aluminum rim.
si de
review b y
comprehensive
it
t he
is
in
topped
has d r i e d ,
If
it
is
the
holes,
any
excess
seen t h a t
Tt
K . o i a t i s , Jhap. V I I I ( I I ) , Bet a- and Gamma-Bay
dpeotro scopy . I n t e r o c i e n c e r u b l i s h o r s " I n c . ~ !7eu York, l b 5 3 .
I CM
\
5
Top View o f
21
oource
tho
foil
t ab
of
and rim do not make c o nt a c t a t
foil
in place
can be folded over the
against
This procedure
between the
source
it
is
foil
recommended to
in the
when t h i s
thin
the aluminum and w i l l
The f il m i s
int o
electrical
not
di s h of
film i s
wet
come o f f
cl ean wat er .
After
treated
dilution
with i n s u l i n
is
The i n s u l i n
that
is
applied
cut
s
out
diluted
approximately
has a very
heating
donsities
which i s
them.
insulin
to
t he
mate a r e c t a n g l e .
the dropper.
treated
of
film i s
the area over t he
buckscattering,
water.
1 part
The
insulin.
poi nt
is
flame.
obt ained
by
The drops are
the dropper between
be used to
spread the
w i l l more c l o s e l y a p p r o x i ­
The excess i n s u l i n
tfhile the
drop of LG 600
from an eye-dropper
The f i n e
area
dryi ng.
The LG 600 fi l ms
water to
of t h e dropper can a l s o
so t h a t
rim and f o i l
after
reduce
and drawing i n a Leeker burner
The t i p
to
0.1 mg/om^.
i n small drops
drawn t o g e t h e r by running the t i p
is
c l i n g s very well
with d i s t i l l e d
20 p a r t s
fine point.
to the
The fi lm spreads over the
the LG 600 film has d r i e d ,
rectangular hole,
is
it
easily
water and may be picked up with a scoop.
used had average a r e a l
e f f e c t s of
p r e p a r a t i o n o f a source
obt ai ned by p i p e t t i n g a d i l u t e d
a l a r ge
cont act
souroe h o l d e r .
wet f il m of Lithgow LG 600 over t h e
arrangement .
to
st e p
insure
tape.
connected e l e c t r i c a l l y
vacuum chamber by means of t h e
lay a t h i n ,
Bide of t h o rim and held
and t her eby l e s s e n t he
The rim i s
The next
a small
by a piece of Scotch e l e c t r i c a l
and rim,
char gi ng.
any p o i n t ,
still
is
next
wot with
removed with
insulin,
a
23
drop o r two of t h e
the
treated
area with an ot he r
Tho i n s u l i n
therefore,
reduces t he
when t he
he more uniformly
dryi ng pr ocess
During the
time w i l l
radioactive
s u r f a c e t e n s i o n o f the
distributed
process,
that
help to
the
increase
source
very s t a b l e
over the
treated
keep
bettor
area.
the
The
lamp.
from time to
scattering.
be used as
f il m of LG 600.
chemi cal l y,
t h i n g to
the
will
from drying non-uni for ml y.
thin
stable
obemioally
o r d e r to prevent
it
source
t h i s manner can e i t h e r
i3 very
uncovered i s
the
f i l m t and,
t he a c t i v e m a t e r i a l
rocking the
covered with anot her
matorial
eye-dropper with a f i n e p o i n t .
source d r i e s
A source prepared i n
i s or
p i p e t t e d onto
can be hast ened by tho use of a heat
drying
al s o
solution is
i'or a c t i v e
l eavi ng tho
do since
the
it
source
covering w i l l
For m a t e r i a l t h a t
is
not
souroe should be covered i n
entire
vacuum chamber from g e t t i n g
con-
taminat e d .
The completed souroe i s
a t t a c h e d to
hol der by means o f a 4-40 screw.
of an aluminum rod which passes
screw i s
at
arrangement
t he t i p
to
of
this
change t he
shown s i nce
used i n s e t t i n g up the
which i s
r a t h e r bulky,
more e a s i l y
It
is
The d e t a i l s
consists
seal.
The
p o s s i b l e with t h i s
of
the
the
source
source
was a temporary arrangement
i n s t r u me n t .
work has been done on the
source h o l d e r
r a d i a l p o s i t i o n of
it
source
through an 0 - r i n g
rod.
while mai nt ai ni ng a vacuum.
hol der ar e not
Tho
t he
Now t h a t
i n s t r u me n t ,
this
tho
initial
source h o l d e r ,
should be repl aced with a si mpl er and
handled arrangement.
24
The souroe p r e p a r a t i o n t e c h n i q u e d i s c u s s e d above
yields
sour ces
produce
the
noticeable
source
possible
is
line
d.
are
reproducible
in
when d i f f e r e n t
strike
6.
high.
minum f o i l .
is
s o u r c e s of
figure
ie
an
a conver ­
as
it
piper
0-ring
is
insure
light.
diameter,
p r e ven t
great
The phosphor
l/3£"
at
the
wrapped i n
seal
is
exit
thick,
shown
slit
l/8"
wide
0.2 mi l
alu­
0. 5 mi l aluminum
located.
A mu met al
The arrangement
no f u r t h e r measures
that
is
the
t ube
The e n t i r e
fringing
t h e mu met al
field
shield.
Jelly
cast
iron
sleeve
7" l ong,
This
s l eeve
is
of
t he magnet
Changes
is
the
from gamma-rays from the
from e x t e r ­
shown i n t he
Good o p t i c a l
at
shielded
apparatus
produce n o t i c e a b l e
end p h o t o m u l t i p l i e r
amount o f pet rol eum
is
shown so t h a t
formance o f t h e d e t e c t o r .
piper
the
covered wi th
and 5 / l 6 ,f t h i c k .
s t r e n g t h do not
shielded
Is
is
detector
focused a t
surrounded with a l a r g e
4#" i n s i d e
sar y to
being
the
p l a c e d over t he p h o t o m u l t i p l i e r .
need be t a ke n to
light
This
can i n t r o d u c e
s e c t i o n of
phosphor which i s
where t h e
light-tight
field
position
± # mm*
sour ces a r e used,
cr os s
The l i g h t
except
shield
too
The p o s i t i o n i n g of
i n t h e val ue of Br f o r
The e l e c t r o n s
the p l a s t i o
and 1 l / 8 "
nal
and -*hich do not
Detector
i n i ’i g u r e
is
sturdy
t o w i t h i n about
source
of about ± i $
A horizontal
foil
reasona bl y
chargi ng e f f e c t s .
variation
uncertainty
si on
that
neces­
from being
i n t h e magnetic
changes
i n the
per­
coupl i ng between the
achieved
Junction,
by u s i ng a smal l
The phosphor
source by appr oxi mat el y
is
PHOSPHOR
i
l
t'-1
v-
Lj
DUMONT
LIGHT
PIPER
6292
m
1
J - =
i"
6
Cross
S e c t i on of D e t e c t o r
£5
£6
1 inoh of
lead.
shown I n F i g .
The d e t e o t o r
1 by means of
The sorews pas s
Is
attached
large
thr ough h o l e s
in
brass
the
The r e g u l a t e d hi gh v o l t a g e
tiplier
used has been 1000 v o l t s .
The s i g n a l
fed
and t he n to
into
flange
D
sorews and n u t s .
supply
laboratory.
is
the
flange.
in t h i s
plier
was b u i l t
to
the
photomul­
The u s ua l v o l t a g e
from the p h o t o m u l t i ­
a pre - a m p l i f i e r b u i l t
an KGX Lionel 2205 l i n e a r
for
in th i s
laboratory
amplifier.
The p u l s e s
from t h e
l i n e a r a m p l i f i e r ore t a k e n from t h e
discriminator
output.
The d i s c r i m i n a t o r
is
to
a r e a d i n g of
used.
timer
75 when t h e f u l l
The p u l s e s
2006 s c a l e r .
from t he
A system of
and s c a l e r
registers
ore
t he
Is
When a source
is
The l a r g e s t
Os
under
i n t he
nature
amplifier is
employed so t h a t
number of
set
an HCL Model
After the
counts,
^ source.
the
rate
in
t he
t he
t he
scaler
same r e l a y
i n s t r u me n t
conditions
is
about
s p e c t r o me t e r
0.7
the
counti ng
In t h i s
Usuall y
the
rate
and
specified
t he
above,
counts/second.
background w i l l
o f t h e source and i t s
background
counts/second.
is
go to
together.
no source
counti ng
depend upon t he
strong
relays
started
is
operated
background
g a i n of t he
usually
timer.
When t h e r e
detector
amplifier
amplifier
a p r e - d e t e r mi n e d
system s t o p s
the
on t h i s
total
activity.
observed was with a
case t tie background was
background
rate
was about
2
1
count/second.
From s t u d i e s on t h e
Cs
it
lower
has been determi ned t h a t
energy b e t a - s p e c t r u m o f
the
deteotor
cut-off
is
27
approxi mat el y
efficient
30 kav and t h a t
around 125 kev.
with t ho s e
that
the
d e t e o t o r becomes 100/o
These v a l u e s
compare f a v o r a b l y
could be o b t a i n e d with a c o n v e n t i o n a l mica
window g o i g e r
counter.
Bata t ake n below 100 kev a r e not
very
since
discriminator
reliable
drift
is
from one s e t
unavoidable,
that
useful
this
with t he
discriminator
thin
is
it
more u s e f u l
strong
since
its
counter*
able
t he
devi ce
s our ces
at
the
counti ng
Al so,
this
and
be made of
ments.
the
the a n ti c i p a t e d
difficulty
noted
present
into
detector
operation
scintillation
loss
is
when f a s t e r
laboratory,
it
far
window count er
will
kinds of measurements.
less
is
than t h a t
electronic
is
was b u i l t
detector
sainti11ation detector
d e t e c t o r w i l l be ne c e s s a r y
be t h e
For
recommended
of
circuits
anticipated
for
sooner t han a
i v e n when a t h i n
certain
is
c o u n t e r be b u i l t
that
a geiger
become a v a i l ­
electron-
gamma c oi nci de nce measurements w i l l be a t t e m p t e d .
scintillation
u s i ng
s p e c t r o m e t e r was about t h a t
The s c i n t i l l a t i o n
for
of
f o r low energy measurements i t
counter.
can
This problem
disadvantages
Because of t he
could be put
window g e i g e r
available,
another.
a t h i n window g e i g e r
spectrometer.
since
has.
t he a m p l i f i e r
Mention should
ra;ige o f t h e magnetic
presently
first
one o f t h e
problem was f o r e s e e n ,
which i t
the
is
detector.
recommended t h a t
in
o f measurements to
and i t
a scintillation
fact
the
The
f o r such measure­
£8
e.
Magnetio R i g i d i t y Measurements
I n a magnetic
baffles,
speotrometer, since
some q u a n t i t y
Binoe r
is
constant,
to
Br.
C a l i b r a t i o n of
is
required
In
t he
since
initial
ured was t h e
that
this
in
to
several
usi ng
of
cour se o f
constant
t he
the
coil
of
was d r i v e n
o o i l was l o c a t e d
to
this
Br v s .
The d e p a r t u r e
trans­
this
trans­
The
that
described
course o f thiB
experi enced
fluctuations
reading,
was of
t he
i n u s i ng t h e
on t he power
These f l u c t u a t i o n s
made
spectrum a d i f f i c u l t
work t h e
f oc us i n g a o t i o n of
Langer and F.
system were d i s c o v ­
from l i n e a r i t y
t o g e t h e r on t he
rotating
potentiometer
synchronous motor.
task.
Q
1.
that
work done with tho
cu r ve,
close
t he
q u a n t i t y meas­
secondary of
features
taking points
made t h a t
sources
unknown.
reading v o l t m e t e r .
system was caused by frequency
In the
is
a r o t a t i n g primary
Another d i f f i c u l t y
feeding the
standard
i n s t r u me n t t h e
a peak
undesirable
1/5.
be p r o p o r t i o n a l
s
The c a l i b r a t i o n
(1950).
also
primary t r a n s f o r m e r was s i m i l a r
was n o n - l i n e a r .
line
will
measured,
the aluminum can shown i n Fi gur e
The emf induced i n
In the
order
B is
The r o t a t i n g
pieces
by Langer and S c o t t .
ered.
to
emf induced i n a r o t a t i n g
former was then fed
coil
proportional
t he p r o p o r t i o n a l i t y
The induced emf vues fed to
rotating
f i x e d by t h e
instrument
work with t h e
between t he pol e
former.
is
quantity
the
by a synchronous motor.
2.
is
r
di s cover y was a l s o
t he magnet
S c o t t , Rev.
Sci.
depends to
Instr.
21,
a
522
29
s ma l l
extent
on t h e p r e v i o u s
h i s t o r y of
the
The
iron.
e f f e c t o f t h i s p r o p e r t y o f t he magnet i s to cause t h e shape
and p o s i t i o n o f a conv er s i on peak to
netic
the
history
same to
of
the
Tho a r e a s
w i t h i n ± 5/o which i s
d e t e r m i n a t i o n o f t he
no problem i n
version
iron.
t he
therefore,
but
it
does
energy d e t e r m i n a t i o n o f t h e s e
the
uncertainty
cycl e
the
reverse
dure.
the
t he
for
one
d i r e c t i o n of
the
current
each experi ment .
magnet
in order
another
ting
factor
coil
to
coil,
t he
o f a number o f
lected
t he
is
to
t he
increase
the
repeated
of
coil,
the p r o c e ­
This l i m i t
five
ia
times
cycling the
results
possible
abandonment o f
difficulties
magnetic
rigidity
current.
standard
reading
in
noted
was
the
rota­
above i n using
determinations
potentiometer
The data
readings.
each case was p r o p o r t i o n a l to
since the p o t e n t i a l
difference
applied
to
the
were
The conv er s i on e l e c t r o n
sour ces were run.
were c o unt s / s econd v s .
potentiometer
current
is
The
system.
made by measuring t h e
tra
t he b e s t
lesson
the magnet
and r e p e a t
375 ma.
The c ycl e
which d i o t a t e d
Because o f
rotating
results
This n e c e s s i t y
obtain
to
d i r e c t i o n t hrough
used i s
causes
accuracy of
In o r d e r
effect
in the
each experi ment .
current
before
l e s s e n the
consistent
The maximum c u r r e n t
ar e
o f con­
intensities
caused by t h i s
t he most
by t ho power s uppl y.
This e f f e c t
lines.
same manner b e f o r e
which g i v e s
and d e c r e a s e
set
in energy
peaks
usual uncertainty
t h e d e t e r m i n a t i o n of t h e
lines,
cycled i n
under t h e
a r e a under a peak.
t he
is
depend upon t he mag­
t he
spec­
col­
The
t he
30
p o t e n t i o m e t e r was t h a t
shown i n F i gu r e
this
4.
laboratory,
t h o 10 ohm Btandard r e s i s t o r
Tho p o t e n t i o m e t e r , which was made i n
could d e t e c t
The o u r r e n t v a l u e s ,
various
across
conv er s i on
expr ess ed
lines
of
ourrent
changes o f
in a r b i t r a r y
as a f u n c t i o n of Br.
plot
far
was l i n e a r as
Any n o n - l i n e a r i t y
or
loss.
This
is
known Br v a l u e s
on t h e
The u n c e r t a i n t y of
are
the
the p o i n t s ,
given by t h e
I
i3 t he
tioning
best
the
of
shown i n Fi gure
each of
these
A least
data.
0.1;£
7.
conver si on
squar es
line
fit
was
so determined
readings
5 3. 0 ,
in
the
i n s t r u me n t
at
(8)
same a r b i t r a r y
3ame c o nv e r s i on l i n e
r uns were r e p r o d u c i b l e
attaching
that
The G s ^ 7 Test
to
caused by source
an u n c e r t a i n t y
3.
units.
i n the manner s t a t e d ,
which the
Br v a l u e s of unknown l i n e s .
is
t he o r d e r
straight
-
expr essed
the
ment
ourrent
from conver si on peaks of
given.
= 1.513 I
current
requires
1 ^7
is
are
This u n c e r t a i n t y p l u s
A Gs
The Br v s .
were
equation
potentiometer
0.3/tf.
rigidity
which
found i n Cs 131t Bal*^ and Bal^^.
would appear on d i f f e r e n t
i
be of
Br v a l u e of
«nfhen o p e r a t i n g
the
line
and the
Br
where
to
curve
l s s o . l ; 5 o f t iie v al u e
made of
is
estimated
that
at
could be determi ned from t h e
calibration
The p o i n t s
peaks
as
units,
known magnetic
found were p l o t t e d
O.Ol^S.
wi t h i n
posi­
o f about ±0.5;o to
Spectrum:
electron
shown i n Fi gu r e
spectrum o b t a i n e d wit h
8.
This
isotope
t he
instru­
has been s t u d i e d
by
5000
Br
(GAUSS- cm)
4000
3000
2000
1500
2500
CURRENT
i ' i g.
7
3500
(ARBITRARY
i-ionentum C a l i b r a t i o n
SI
UNITS)
Curve f o r
Spectromet er
K 66
COUNTS/SECOND
600
400
L P
O . 8 V.
200
L+M
661
800
. 200
CURRENT
i ’i g .
8
1600
2000
(ARBITRARY
Gs-'-*7''7 E l e c t r o n
32
UNITS)
Gpectruni
33
a number of
la
worlcers.9- ^
shown i n Fi gur e
test
9.
This
t he performance of
reliable
Tho g e n e r a l l y
spectrum was s t u d i e d
t he
instrument,
momentum o a l i b r a t i o n p o i n t ,
sity
of
t he ^ - c o n v e r s i o n peak.
tion
is
used to
transitions
determi ne t h e
of
and t h e
to
last
conv er s i on
i n o r d e r to
o b t a i n a very
and to
This
i n Bo134 and Gs131.
s o u r c e s were used,
aooepted deaay aoheme
o b t a i n t he
piece
of
i nf or ma­
coefficients
Actually,
several
spectrum shown i s
inten­
of
Gs137
from Just
one
these.
Cesium 137 was chosen f o r
the
i n s t r u me n t
since
it
s i o n p e a ks .
Since t h i s
gated
other
by t he
lived
o bt ai ned
a good i s o t o p e
and i s
isotope
f or
obtainable
has been t horoughl y
their
from t h i s
testing
wit h a high
results
s i nce
specific
conver ­
investi­
can be
instrument.
pur poses
The spectrum shown i n F i g .
souroe p r e p a r e d
t h e performance of
both a continuum and
workers mentioned,
compared wi th t h o s e
137 i s
provides
testing
Cesium
it
is
long-
activity.
9 was o b t a i n e d
from a t h i n
i n t he manner d e s c r i b e d p r e v i o u s l y .
The
£
areal
density
of
this
was appr oxi mat el y
made ol
1272
the
dat a
9
G, L.
(1949).
(1949);
Graves,
source was — 0 . 1 mg/cm .
o/lu"
wide and 1 ” h i g h .
shown i n F i gu r e
Peacook and A.
Q.
The source
A Fermi
This p l o t
G. iwit oh e l l ,
is
Phyc.
plot
was
shown i n
dev.
75.
X(^L. II. Langer and H. G. P r i c e , Phys. Fev. 76^, 641
L. ti. Langer and rl. J . i^oflat , i b i d . 82, 635 (1951);
Lunger and l o f f a t , i b i d . 68 . 344 (195 2 1".
1Xl:. A.
Waggoner,
Phys.
lev.
82_,
906
(1951).
137
137
Ba
CS
i *
.51 ME V 0 2 •/•)
156 S E C .
2
1. 17
ME V ( 8 °/o)
. 6 6 1 MEV
<M4>
3 _ t
i' ig.
9
Decay Scheme f o r C s ^ 7
D4
4C . - +
35
i'igure
that
10.
The upper
Tooth t he
is
vi ous
It
be 511
resu lts.
lower energy
unique
is
obvious
n o t ral l owed.
was found to
It
is
known t h a t
oeta group
the
energy
to
total
in
the
subtracted
t he
of
tho
line
-
a z
energy
upper curve
l
is
total
is
test
indicates
in
have
reported
transition
mat ely 4 . 3 .
that
history
the
values
i n Ba
137
•
plot
p
units
higher
( s )
and
»iL i s
o
beta
is
group was
a straight
The bending over
results
from l e s s
lo .v e n e r g i e s .
of numerous
slight
not
hnae
with g e n e r ­
investigators,
dependence of
i r o n does
end -
lower curve.
The r e s u l t
these
the
o f appl yi n g t h i s
energy
130 l e v .
results
the
by u s i ng t h e
The r e s u l t
at
of t h i s
l i n e , i n agreement
of t he
intensity
several of
transition
w)2 ,
shown i n the
a straight
this
error
beta
a-^ , whioh i s
lower t han t h i s
accent ed e x p e r i me n t a l
p re vi ous
beta
i’ermi
spectrum.
ally
able
this
fwQ -
in nrc
o
f a c t o r t ho
energies
lower curve
on t he
+
■xi energy o f about
at
have
lower energy
oan be made l i n e a r
t h a n lOO/o d e t e c t i o n e f f i c i e n c y
t he
the
t he
same u n i t s .
from tho
down to
assuming
2 0 k e v , i n good agreement wit h t h e p r e ­
Before appl yi n g t h i s
line
that
f i r s t - f o r b i a den shape f a c t o r ,
where W i s
factor
from f i r s t
The energy of
&1 ( w ) *
point
resulted
1.17 Mev and 0.51 Idov b e t a - s p e o t r a
al lowed shapes.
group
ourve
f oc us i n g
cause a
notice­
measurements.
investigators
lor
previously
the x»./(l+ld)
ratio
Waggoner obt ai ned
Graves , Langer and L o f f e t
of
mentioned
the
G61 kov
a val ue o f a p p r o x i ­
u s i ng a magnetic
6
6
4
2
ME V
OL_
1.0
I8
I.4
I
(i + p ) 5
O
Pi g.
10
Permi
36
Plot
for
2.2
37
spectrometer with g r e a t e r r e s o l u t i o n obtai ned 4.6 ± 0 . 3 ,
experimentally determined values of the k / f L + l l )
half-life,
enci the
t i o n are a l l
conversion c o e f f i c i e n t
f or
The
ratio,
this
the
transi­
compatible with an 114 assignment* for t h i s
tran­
sition.
In t e s t i n g the spect romet er,
the
the h / f L + i . )
661 kev t r a n s i t i o n was determined i n order to
ratio
compare
the value obt ained with the above mentioned r e s u l t s .
ratio
of
This
was found by measuring the area3 under the if and L+M
peaks.
The value obtained was 4 . 5 * 0 . 5 ,
i n good agreement
with otiier work.
Using liq.
(7),
momentum r e s o l u t i o n .
si i'.e used i s
one can a 1 oo compute the
The expected r e s o l u t i o n i o r
about 0.006.
As shown in i ' i g.
t i o n obtained experi mentall y i s
about
8,
instrument
from the data shown in I' ig.
known A-coaversion c o e f i i o i e n t
which i s
0.U84.
of
the
the
source
the r e s o l u ­
O.JOQ.
One can also make an est i mat e of the
the
expected
t rnnsmissi on of
8,
using the
661 kev t r a n s i t i o n
One can writ e
a
=
(paafcl. ,
do)
*/1o t a l
where a^ i s
the k-conversion c o e f f i c i e n t ,
t r a ns mi s s i o n of t he
of
4ff
i ns t r ument ,
total
661 kev gamme-rays emitted from the
storadians,
and Ne (peak)
the K-conversion l i n e .
is
i®
T is
the
desired
total
source per
number
second i n
‘t'he P°alc counting r a t e
The t o t a l gamma-ray a c t i v i t y
of
from
the source waB c a l c u l a t e d from measurements made with a
38
scintillation
putting
spec t r ome t e r .
i n tho known values
o b t a i n s a t r a n s m i s s i o n of
the t r a n s m i s s i o n i s
al so
Those f i g u r e s
compure favor abl y
type
.
s o l vi ng ^q.
for
0*2^,
about
for the
(10)
f or
T and
the remaining t e r m s f one
The t h e o r e t i c a l
value f o r
Q.2,o.
r e s o l u t i o n and t r a n s mi s s i o n
with those of o t h e r
i ns t r ument s o f t h i s
CHAPTER I I I
the
1*
r : t jh;.i i hati j n
of
goijversioii
, where
is
second f o r a p a r t i c u l a r
nitions
oan be made f o r
The H/L r a t i o
is
a^ , 1 b d e f i n e d
t he number o f K - e l e o t r o n s
transition
of gamma-rays e mi t t ed p e r second.
and Uy i s
Entirely
lated
defined
by Rose et_ a l .
calculated
t he
pole
of
one knows t h e
t he
atomic
trons.
say,
associated
number and t he
The r e l o r e ,
t i o n wi th t h e
the
number
analogous d e f i ­
o rbital
comparison of
coefficient
t h e o r e t i c a l values
determi ne t h e m u l t i p o l e
hr.ve been c a l o u -
conver si on c o e f f i c i e n t s
transition
involved,
radiation.
conv er s i on c o e f f i c i e n t ,
t h e A- conversion
one to
The t h e o r e t i c a l
atomic o r b i t a l
the
e mi t t e d
as Fl/L = a^/a-^.
as a f u n c t i o n of
atomio number,
character
12
the
as
t he U and H-oonversion c o e f f i c i e n t s .
The K and L- oonver si on c o e f f i c i e n t s
are
>:irro
Importanoe o1 Conversion C o e f f i c i e n t s and K/L R a t i o s :
The A-oonversion c o e f f i c i e n t ,
per
cosfiici
for
the
ener gy,
the
and t h e m u l t i ­
from experiment
the
transition
energy,
the
conver si on e l e c ­
e x p e r i me n t a l v a l u e o f ,
for
will,
a particular
transi­
in p r i n c i p l e ,
c h a r a c t e r of
the
permi t
radiation.
12
Rose, G o e r t z e l , o p i n r a d , Harr and s t r o n g , Phys.
Rev. 93, 79 (1951) ;
id. E. Rose, Appendix IV, B e t a - and
Gatnma~=iTay Bpeotro soopy . I n t e r s c i e n c e P u b l i s h e r s , I n c . ,
l/ew York, 1955.
39
40
Having determined
selection
total
rules
the m u l t i p o l a r i t y o i
resulting
radiation,
the
irom c o n s e r v a t i o n of p a r i t y
and
a n r u l a r momentum f o r t h e
the
system,
nucleus p l u s photon,
p e r mi t s one to make some st at ement about
momentum change and p a r i t y
the nucl eus
total
f or
nucleus
is
can be determi ned,
and p a r i t y
known, and i f
each oi
of
nucl eus.
to
the e x c i t e d
states
total
reason why such s t u d i e s ar e made.
ex a l t e d
edge of
are of
e n e r g i e s of
The JC/L r a t i o
with the
t h e o r e t i c a l val ues
1'rom the p o i n t
the v a r i o u s
of
using the ii/l* r a t i o
determine t h e m u l t i p o l a r i t y
the ix/L r a t i o
intensity
of
of
all
that
The advantage
is
required Is
whi le,
t i o n appears to be
is
that
the b e t t e r
t he
in p r i n c i p l e ,
i n determining t he m u l t i p o l a r i t y
way to make t h i s
of
in
of a
coefficient
the 1-oonver s i on peak be compared to
the 1-oonversi on peak.
t he I-/ii r a t i o
depends
do not have to be determined.
determine
sity
radiation.
over usi ng the 1 - c onver s i on
gamma-ray i n t e n s i t i e s
the knowl­
levels.
upon t he m u l t i p o l a r i t y
transition
of
of the v a r i ­
of a n u c l e a r t r a n s i t i o n a l s o
to
in
experi­
as much importance as i s
the
the
of the
levels
the
t he a n g u l a r momenta and p a r i t i e s
levels
the
ex c i t e d
by comparison of
is
ous
If
to make these assignments
conversion c o e f f i c i e n t s
view of t h e o r y ,
involved*
angular momentum
the
mental
t he
experienced by
changes between l e v e l s
each of
The a b i l i t y
angul a r
the ground s t a t e
the
then a d e f i n i t e
can be assi gned
t he product
any,
the p a r t i c u l a r t r a n s i t i o n
an gu l a r momentum and p a r i t y
product
to
change, i f
t he t o t a l
that
To
t he
inten­
use of
a transi­
determination.
41
In p r a c t i c e ,
diffioulties
r e s o l u t i o n of
gies
in
t he
a r e met
i ns t r u me n t
excess of
because of
used i n
the
such s t u d i e s .
l o r a momentum r e s o l u t i o n o f about
K/(L + Li) r a t i o
mentally
is
the
under t h e
quantity
that
ci roumst anoes
is
are
i ’o r t h i s
tity
as
no r e l i a b l e
ratio.
Because of
determi ne
the
the
not
t he
While r e l i a b l e
are
this
as
available,
was the
of
investigated.
ex pe r i me n t a l
useful a
c i r c u ms t a n c e ,
coefficient
were used as a check on t h e
comparison of
is
t he m u l t i p o l a r i t i e s
from the v a r i o u s t r a n s i t i o n s
ratios
Ther ef or e
t h e o r e t i c a l U- conversi on c o e f f i c i e n t s ,
work r e p o r t e d t h e h - c o n v e r s i o n
most used t o
L
determined e x p e r i ­
specified.
reason the K/(L + I.I) r a t i o
t he h / l
t he
from t h e
O.B^.
t h e o r e t i c a l X and L- oonver si on c o e f f i c i e n t s
there
At e n e r ­
300 kev and f o r medium 2, i s o t o p e s ,
i i -oonverei on e l e c t r o n peak cannot be r e s o l v e d
peak
finite
the
quan­
i n t he
quantity
radiation
The £./fh + i.i)
conclusions
reached
from
and t h e o r e t i c a l 11-
conversion c o e f f i c i e n t s .
2.
Method o f Determining Conversion Co e f f i c i e n t s ;
In d e t e r mi n i n g t h e
conver si on c o e f f i c i e n t s
with v a r i o u s n u c l e a r t r a n s i t i o n s ,
tive
t he
intensities
relative
of
t he
intensities
one begi ns
gamma-rays i nvol ved
o f t he
version
and gamma-ray i n t e n s i t i e s
so t h a t
t he
conver si on
The r e l a t i v e
isotopes
studied
t he
rela­
decay
and
cor re spondi ng conver si on
Borne means must be found to
tion
with t he
in
electron lines*
electron
associated
relate
for
t he
con­
each t r a n s i ­
c o e f f i c i e n t s may be determi ned.
gamma-ray i n t e n s i t i e s
for
t he
were o b t a i n e d wit h a s c i n t i l l a t i o n
radio­
42
spectrometer.
The method used i n d e t e r mi n i n g t h e
intensities
various
ustrated
oi
conver si on e l e c t r o n l i n e s
by c o n s i d e r i n g t he
t h e Ic/fL+ii)
ratio
ior
the
way i n
ex pe r i me n t a l
661 kev t r a n s i t i o n
data
under
t he L
rigidity
of
the
peak i n t he
a r e a of
the
L ■+11 peak,
magnetio
is
that
rigidity.
the
t hrough the
with the
exit
flux
mined f o r
used
spread
essentially
calculated
areas.
slit
of t he
studies
in
dividing
s p e c t r ome t e r
Therefore,
r
is
the
Br,
ratio,
in
to
t he p o s i ­
Likewise
the
the
the
yields
be r e f e r r e d
is
electron
one
to
a r e a by Br
that
pass
linearly
area
deter­
i n s t r u me n t
areas
that
are
Areas
so
a s normali zed
proportional
line
the
appropriate
u n i t momentum i n t e r v a l .
future
conver si on
since
d i v i d e d by
increases
dividing
constant,
Low each normalized a r e a
the L/fL+Id)
, i s n e xt
i n momentum of t h e e l e c t r o n s
density.
will
The a r e a s
determined wi t h c
d i v i d e d by the
The reason f o r
normal i zed t o
c o r r e s pondi ng
for
scales.
momentum spectrum.
each peak by B, or
in t h e s e
L + M composite
value a p p r o p r i a t e
» is
The
begun by p l o t t i n g
The a r e a o f the L p eak,
average magnetio
tion
suitable
peak and t he L + H peak a r e
planimeter.
t he
is
in
t h e K peak and the
peak on l i n e a r graph paper t o
can be i l l ­
which one can determi ne
d e t e r m i n a t i o n of t h e K./fL + 1-l) r a t i o
from the
relative
intensity.
to
t he
fherelore ,
can write
'
(11)
L + H
since
is
the
t he p r o p o r t i o n a l i t y
same and w i l l
constant
c an cel
in
the
for
each normali zed a r e a
ratio.
43
The . ^-conversion
transition
coefficient
theoretical
lations
val ue
of
0. 094.
in t h i s
mine t h e
661 kev,
0.097*0.005.
i o r 1*14 r a d i a t i o n
The t h e o r e t i c a l
M4
value
of t h i s
was used
the a n a l y s i s
energy from
in
of
1'he
the
the
calcu­
dat a
paper.
The use o f
the
conv er s i on
in a radioisotope
f our
is
which were performed i n
reported
t he
has been determi ned wi th good accuracy by
.naggoner.1'*' Waggoner's v a l u e o f
B a ^ 7 is
for
661 kev t r a n s i t i o n
coefficients
of
i n Ba1^ 7 to
the v a r i o u s
under i n v e s t i g a t i o n
involves
deter­
transitions
essentially
independent measurements , two measurements bei ng made
on each of
two
sources.
tron
source of
t he
tron
source o f
Cs
alike
radioisotope
137
as p o s s i b l e .
•
The two
sour ces
consist
the
various
conversi on
s p e c t r o m e t e r and the
sources
of
electron
relative
lines
normalized a r e a s
with
gamma-ray
see more c l e a r l y
f o l l o wi ng g e n e r a l
case.
under i n v e s t i g a t i o n
tion
i s X kev.
whose energy
associated
second from the
with
source
associated
with t h i s
t he
is
source
and an e l e c -
a r e made as n e a r l y
d et e r mi ni n g t h e
of a radioisotope
electrons
studied
of
the magnetic
intensities
wi th t h e
spectrometer.
I n o r d e r to
c o n s i d e r t he
being
The two measurements made on each o f t h e
two
scintillation
The two so ur c e s used a r e an e l e c ­
H(Y)X.
what
is
involved,
I nvolved i n t h e
is
a certain
decay
transi­
The number of ± - o o nv e r s i o r
this
is
transition
transition
and e mi t t ed
The number of
and e m i t t e d p e r
The cor respondi ng terms
per
gamma-rays
second from
lor
t he
06^37
44
source a r e
and 11^^661*
met er d a t a ,
in Ba
1 rS7
study a r e
areas
the
^rom t he
and t he X kev t r a n s i t i o n
and I i ( e . . ) v
n x
in the
The r e l a t i o n s h i p s
and B(e, ) , , , ,
k 6ol
Nfejj.)^.
spectro­
for t h e t-conTersion peaks
normali zed a r e a s
obtained.
magnetic
radioisotope
between t he
under
normalized
are
and
r kA* ( e ^ ^ ,
N^ek^661 = ^
(12)
^°k ^661 *
(13)
where A' (e, )_ i s now to be used f o r the normalized a r e a s ,
k x
1'rom the
scintillation
spectrometer,
if (‘f ) £ 5 i/l* (^ )x . t he
ratio
661 kev t r a n s i t i o n
from t he
intensity
of
the
investigation.
.a. kev
of t he
framma-ray
source
transition
(14)
ak
-
to
the
of
t he
gamma-ray
source under
By d e f i n i t i o n ,
can al s o
av
intensity
irom t h e
• ‘X =
Eq.
one can o b t a i n
•
be w r i t t e n a s ,
J j J e jt J -X
l U ' f
)x
Xif y >6 6 1
i a y ) 661
lUe)JnfVl
=
(14)
a k_ = (0.094)
^ ek)661
N(ek ) 661
s;________Li { *
A' .(.e^
J 6 61
or
(15)
# or
f1G)
’
---------
(17 )
<e k >661
Prom Bq.
(17)
ficien t , lor
it
is
evident
that
an X kev t r a n s i t i o n
can be determined
from the
a kx * t h e X-conversion c o e f ­
i n an i s o t o p e
results
of
t he
under
st udy
measurements
45
indicated
the
and
the t h e o r e t i c a l K- conversi on c o e f f i c i e n t
661 kev t r a n s i t i o n
The method
conv er s i on
in
d i s c u s s e d above f o r
coefficients
is
u s u a l methods employed i n
somewhat of
the
d e t e r m i n a t i o n of
a departure
d e t e r mi n i n g t h e s e
common methods r e f e r e n c e may he made to
3.
of Method f o r P e t e m i n i n g
The method
si on
coefficients
conversion
i n Ba
was used
coefficients
Ba^-*^ i n o r d e r t o
tions
described
134
teat
in tho
ol
the
t he
have e n e r g i e s
have
reoently
reasonable
these
and because
studied
agreement
on
for
conver ­
d e t e r m i n a t i o n of
two p r i n c i p a l
the
transitions
The two p r i n c i p a l
605 kev and
various
797 kev.
of
conver si on
of
Os
These
their
are
coefficients
in
transi-
i n v e s t i g a t o r s ^ 4"^^
disintegration
the
Hitohell. ^
de t e r mi ni n g
were chosen because
the
the
of
For
Conversion C o e f f i c i e n t s :
method.
two p a r t i c u l a r t r a n s i t i o n s
intensities,
above
from tho
quantities,
t he mere
Teat
for
high
who
in
for
transitions,
13
•a., C, G. M i t c h e l l , Chap. VI I , Bet a- and Gamma-Bay
Spect ro sconj . I n t e r e c i e n c e P u b l i s h e r s , I n c . , Hew York, 1965.
Akad,
Cim.
■
*"^ B a s h i l o v , Ant oni eva, Blinov and Dzhelepov,
Uauk. Ser. F i z . 18., 43 (1954).
2,
•^Gr.
273;
B e r t o l i n i , 11. B e t t o n i
1., 746 (1955).
F o r s t e r and J .
17
G. L. K e i s t e r ,
451 (1955).
Kev.
97,
Kev.
IQ
Cork, Le Bl anc,
90, 444 (1953).
B.
and B.
Wiggins,
B.
Phys.
Lee and F.
Hester,
Lazzarini,
kev.
H.
99.,
Izvest.
Uuovo
(1955).
Schmidt, Phys.
Marti n and P r i c e ,
Phys.
46
The work of
leister
et_ a l .
wan oho sen a s
comparison pur poses because t h e i r
results
r e o e n t , t h e i r method o± d et e r mi ni ng
reliable,
and
ment
t hose of o t h e r
.i«i t h
report
the v a l u e s
a ^-conversion
605 kev t r a n s i t i o n
was a r r i v e d a t
other
lor this
assignment
for
the
sion c o e f f ic ie n ts
for
x
to
the
the
et
al.
could
transition
since
for
other
transitions
was 0 . 5/o.
if’o r t h i s
are
practically
way,
and t he
ratio
momentum r e s o l u t i o n
resolution,
r es o l ved
conv er s i on e l e c t r o n
t he K / l
at
about
intensities
relative
t he
gamma-ray
of
the
797 kev
the
605 kev
ratio
and
with an i£2
5.19 x 1^“ ^ i s
this
605 kev r a d i a t i o n ,
determine
t he
t he
t h e 12/ l
mined i nd epe nd ent l y o f any knowledge of t he
leister
lor
1Q~^ f o r
ooelficient
agree­
_3
10*3 f o r
The val ue of
seems
et_ a l .
10
were compatible
radiation.
E£ assignment
i-eister
5.1a x
of
the most
ooeflioients
by n o t i n g t h a t
transition
are
in r e a s o n a b l e
■ 5.19 x
t h e t h e o r e t i c a l K-conversion
with t he
are
( 2. 5 ± 0 . 1 5 )
transition
the
investigators.
The v al u e o f a ^
transition.
data
obt ai ned
ooeffioient
and
t he main work l o r
transition,
the
conver ­
can be d e t e r ­
decay
ol
scheme,
tho
their
005 kev
i ns t r u me n t
L and k - c o n v e r s i o n peaks
600 kev.
The r e l a t i v e
were determined
intensities
by usi ng a thorium r a d i a t o r and s t u d y i n g t he
i n the
usual
were determined
photoelectrons
produced by the v a r i o u s monoenergetic gamma-ray groups.
noted previ ousl ; / , l o r
Ikev, t h i s method of
sities
is
performed
gamma-ray e n e r g i e s
d et e r mi ni ng
r e a s o na bl y a c c u r a t e .
experiments wi th t h e i r
i n excess of
0. 5
relative
gamma-ray i n t e n ­
In f a c t ,
leister
i ns t r ument
et_ a l .
i n o r d e r to
As
47
verify
ties
the
that
were r e l i a b l e
relative
various
t he
feet
above 0. 5 ilav.
conver si on e l e c t r o n
conversi on
605 kev,
f o r the
«uoh measurements of gamma-ray i n t e n s i ­
two s e t s
of
*1
The
beta
in
cont i nuous
electron
Os124.
655 kev.
that
intense
primarily
evident
that
other
comparison
there
from the
of
is
in t h i s
be
The p r e s e n t
composite
data
of
who have
of g r e a t e r
e n e r g i e s of
said
the
about
is
shown i n i ' i g.
t he
resulting
the
the v a r ­
concerned
605 kev and
a weak s a t e l l i t e
making up p a r t
8U kev and
among t he v a r i o u s
discussion
of
four
d i e i n t e g r e t i o n of
agreement
will
11.
least
of approxi mat el y
ilore
weaker t r a n s i t i o n .
decay o f
from a t
number and e n d - p o i n t
investigators
this
the
conv er s i on peaks
with i n s t r u m e n t s
observed
since
shown i n .Figure
bets-spectra
While from the
801 kev t r a n s i t i o n
peaks ,
the
later.
kev t r a n s i t i o n s .
in
energies
beta-spoctra.
with t h e
work i s
i nvol ved
iE some lock
ious b e t a - s p e c t r a
not
are
a s to
as a medium of
spectrum r e s u l t s
end-point
There
investigators
less
the p r e s e n t
The two p r i n c i p a l
spectrum have
served
spectrum r e s u l t i n g
^ obtained
cont i nu e
could be c a l c u l a t e d
the
intensities.
The e l e c t r o n
Os
and gamma-ray i n t e n s i t i e s ,
coefficients
62 t r a n s i t i o n
With a knowledge of t h e
797
11 i t
is
from a
797 kev conver si on
s t u di e d
resolving
Because of
the
decay o f
power have
this
fact,
conver si on peaks ar e l a b e l e d 797 & 801.
T6kA
Two Gs
s p e c t r a , one of which i s shown i n l i g .
the
resulting
were
r un,
tical.
and f o r
The
same
all
practical
source
purposes the
.va3 s t udi ed
two
wit h a
11,
were i d e n ­
scintillation
605
K 569
K 563
K
7 9 7 ( a 801)
2
O
605
COUNTS/SECOND
L+M
L+M 797 (0i 801)
O
1040
BACKGROUND
2
2000
2200
2400
CURRENT
Pig.
11
2600
(ARBITRARY
Partial
2000
3000
UNITS)
El ect r on Spectrum
48
3200
49
spect romet er .
Of the data obtained with the
spect romet er,
sitions
only inl ormat i on on the
was used i n t h e
since t he
intensities
magnetic
1 *57
work of
Gabro
obtained
data are
shown in Figures
12 through 1G.
the
scintillation
Os
this
is
1 37
sources was to
st udi ed 'with the magnetic
The reason f o r
Both of the
a film of LG 600, while
Os
while the
o t h e r was
was l / 8 "
using d i f f e r e n t width
the Cs
134
fests
as a t a i l
on the
19
A. Oabro , id. s.
s t a t e U n i v e r s i t y , 1955.
sources were covered with
source was not
covering a source i s
Oource s c a t t e r i n g of
covered.
to i ncr ea s e the
amount of
conversion e l e c t r o n s mani­
low energy si de of
Thesis
source
corresponding conversion
137
scattering.
itself
the same
determine experimentally what e f f e c t
electron l i n e s .
of
For
The Os'1'34 source studied
width has on the a r e a s under the
The r e s u l t
of the data
spectrometer.
sources
wide and 1” high.
all
GG1 kev gam: a-roys were
spectrometer was ’i ” wide and 1" high,
wide and 1” high.
Only
f o r the Cs^3^ sources were obtained
only the photopeaks of
with the
et a l .
spect rometer.
determine conversion c o e f f i c i e n t s .
One of the
l/l6"
and L e i s t e r
sol n t i l l a t i o n
with t he magnetic spectrometer since
reason,
19
sources were prepared and st udi ed with the
the ~-coaversi on l i n e s
needed to
on here
of t he other gamma-rays r e l a t i v e to
spectrometer and the
All of these
797 and 801 kev t r a n ­
c a l c u l a t i o n s to be reported
these are known from the
Two Os
scintillation
(unpublished),
the peak.
Louisiana
5 6 3 ,5 6 9
a
605
KEV
a
801
KEV
COUNTS/SECOND
797
500
700
600
PULSE
1£
Partial
800
HEIGHT ( A R B I T R A R Y
I3a^^
900
UNITS)
Oamma-Ka.y Opoctrum
50
IOOO
( l / 8 ,T Source)
661
—
COU N T S / S E C O N D
10
KEV
, —
600
500
PULSE
i ’i g .
13
Partial
700
800
HEIGHT ( A R B IT R A R Y
Ba
1 ^*7
Gamma-riay
51
900
UNITS)
bpectrum
(1/16"
bource)
2
O
COUNTS/SECOND
661
KEV
O
I __
400
500
PULSE
iig.
14
Partial
600
700
HEIGHT (ARblTRARY
Ba1 3 7
800
UNITS)
(lamma-Ba;/ Bpectrum
PO
900
{*" Source)
800
COUNTS/SECOND
600
400
200
O
2080
i'ig.
15
2160
2240
CURRENT (ARBITRARY
UNITS)
K-Conversion Peak of Ba^*^
{4 " Source)
2320
COUNTS/SECOND
300
200
100
2260
2180
CURRENT (ARBITRARY
Big.
16
il-Conversi on Peak ol
54
2340
UNITS)
BaT37
f l / l G ” Source)
55
Such a t a i l
is
cl cr vly
K-conversion peak o f
evident
t he
in
Pi g.
15 which
561 kev t r a n s i t i o n
shows t h e
f o r the
wide
souroe.
The photopeoks of
needed
14.
in
the
counts p e r
peaks were determined
in t h e photopeak,
intrinsic
urements
The source to
This
The r e s u l t s
In the
crystal
distance
obtained
c onvor si on c o e f f i c i e n t s
I are
by K e i s t e r
expect ed
tabulated
et
a l . are
theoretical
also
797 kev and
data
from the
I.
data
The v a l u e s
determined
I,
II
same in
The Ashown i n
of
given
along wi th the
(private
II,
entirely
data
ar e
and photopeak
301 kev t r a n s i t i o n s .
Bel l
was the
shown i n Table
conv er s i on l i n e
it.
lor
co nv er s i on e l e c t r o n
shown i n Table
seen i n Table
the
dat a
and s p e c t r o me t e r
distance
II.
i n Table
composite
20
t he
gamma-ray meas­
shown i n Table
was not
the
strike
was 53.5 cm.
797 kev t r a n s i t i o n
As i s
second
values.
Concerning t h e
I.
areas
counts per
crystal
calculated
in Table
pho t o ­
normali sed
different
from t he
and gamma-ray measurements a r e
Table
t he
various
by u s i ng B e l l 1s
same 14-" x 1 " Uni (Th)
each exper i ment .
the
number of
second was c a l c u l a t e d
t he
in
thr ough
12
number of gamma-ruys t h a t
peak e f f i c i e n c y .
were us ed.
second
i ’rom the
the
gamma-ray t r a n s i t i o n s
shown i n i ' i gu r e s
by c a l c u l a t i n g
photopeakc,
c r y s ta l per
various
comput ati ons ar e
The number o f
under t he
the
a,
for
from t h e
reported
resulting
To determine
communication).
the
data
for
from
n value
56
TABLE I
3UAG.IAHY OF L/VT/i FOB DZTEBLO. UIIIO a ^ ’ B OF Ba
1 34-
Source
Used
Transition
(kev)
Cs1* ^ , 1 / 8 "
uncovered
797 & 801
605
100
Ga1 3 7 t l / 4 "
covered
661
138 0
1370
CB1 3 7 , l / l o n
covered
661
394
464
#
1s / s e c
on i t a l
A* ( k) x 10 3
4030
3700
218
TABLE II
l l -couversi oi i o o e f f ig i i n t s
Energy
(kerr)
ak x 1 0 3
G81 3 7 ^ h
a I,V x 1 0 3
Os1 3 7 fl / l 6 "
a^ x 1 0 3
of Ba1 3 4
x 103
(ave r a g e ) Kei a t e r
797
2.6
3. 0
£.8
605
5.3
6.2
5 • 8 ± O. 6
±0.3
2.5 ±0.15
5.2
ak x 1 0 3
theory
2.7
5. 2
57
of
f o r t he
et
a1.
had to
and gamma-ray
tions.
the
be used f o r t h e
c o n v e r s i o n peaks
intensities
Actually,
small,
since
intense
tion
7 97 kev t r a n s i t ion a l o n e ,
as
the
the
the
correction
the
ably
with t h o s e o b t a i n e d
coefficients
appears
to
but not
enough to
cause
sour ces
only about
If
t he
to
by l e i s t e r
in
II
15/o as
coefficient
than t h a t
It
Is
e v i dent
Source width
results
obtained,
si nce
used were pur posel y made c o n s i d e r a b l y
the
d et e r mi ni ng t h e
source.
study o f the
two
illustrates
v al u es
1 ^4-
alike
it
decay,
is
felt
two
differ-
source
dimensions
as p o s s ib l e .
that
t he
t h e method developed
for these
the
I n appl yi n g t h e method
conver si on o o e l f i c i e n t s
that
given.
,.ork compare f a v o r ­
et_ al_.
the
I is
901 kev t r a n s i ­
cause a qy concern e s p e c i a l l y
In conclusion,
reliable
data
is
in t h i s
some d i f f e r e n c e
were made as n e a r l y
134
i n Table
t he
shown i n Table
obtained
i n width from t he Os
developed
Ba
to
r e s u l t i n g ^-conversion
results
the
ent
‘301 kev t r a n s i ­
797 kev t r a n s i t i o n would be 10yo l e s s
that
137
of
797 kev and
797 kev t r a n s i t i o n .
.From t h e
Cs
the
801 kev t r a n s i t i o n
were n e g l e c t e d ,
for the
of
ratios
d a t a of K e i s t e r
coefficients.
work done on
discussed
does y i e l d
for
CHAPTER I V
THE Cb1 3 4
1.
Previous
B3TA-3PECTRA
Work:
Table I I I
have found f o r the
summarizes the
beta-spectra
end-point
resulting
energies others
from t h e decay
of
Os134.
TABLE I I I
MAXIMUM ENERGIES OP Gs1 3 4 BETA-SPECTRA
fKEV)
Bertolini
et a l .
Bashi l ov
et a l .
06
Porster &
Wiggins
70
88
Cork
et a l.
Leister
et a l .
80
~5T0
83
£10
"
310
335
o
H
645
6 S0
657
654
Prom Table
III
It
is
410
657
655
68 3
evident
that
there
is
agreement
on a low energy b e t a - s p e c t r u m o f approxi mat el y 83 kev maxi­
mum energy
and on a hi gh energy
energy o f about
655 kev.
weaker components l i e
speotra.
There
is
There
spectrum wit h
is
between the
also
di sagr eement on how many
83 kev and 655 kev b a t a -
di sagreement
58
a maximum
on whether a weak b e t a -
59
spectrum e x i s t s with an end-point
kev.
Ke i s t e r et^ a l . r a t h e r
of the Gs
134
energy of from 68 3 to 690
carefully
i nv e s t i ga t e d the p a r t
beta-spectrum in the region of 690 kev.
investigators
compared the
Cs
134
These
147
r e s u l t s with a Pm
spec­
trum obtained with t h e i r instrument which was operated under
the
same conditions i n obtaining both speotra.
147
the behavoir of the Pm
ana the
Ca
134
b et a - s peot r a near
t h e i r r e s p ect i ve end-poi nt s. K e i s t e r e t _ a l .
t her e i s
a higher energy beta-spectrum.
p l o t of the
Gs
134
beta-spectrum,
By comparing
concluded t hat
In making a Permi
these i n v e s t i g a t o r s found
a maximum energy of 683 kev f o r t h i s high energy spectrum.
£.
Present
Work:
The Gs
134
reported here i s
e l e c t r on
spectrum obtained in the work
shown in Pigure 1 1 .
The source ma t e r i a l
was obtained from the Oak iiidge National Laboratory.
chemistry was done on t h i s m a t e r i a l .
No
In studying t h i s mate­
r i a l over approximately a six month period,
observed t hat
could not be a t t r i b u t e d to
In Pig.
11 the p or t i on of the
mately 500 kev to 1 klev i s
shown*
spectrum above 10 counts / sec,
obt ained,
ana
p or t i on of the
for
spectrum from approxi ­
Por t h a t p a r t of the
statistics
were usually
part below 10 count s / sec,
Z>fo.
The
spectrum from 500 kev to 1 Mev was analyzed
because from the
energy,
t hat
1
no changes were
1 rx,A
the decay of Gs
f i gur e i t
low i n t e n s i t y
excess of 800 kev.
i s apparent
t hat
t her e i s a high
continuum with a maximum energy in
60
In f i g .
subtracted.
background
One can r e a d i l y
the high energy
beta
11 t he
component
continuum of f i g .
fermi p l o t ,
the bet a
components,
the
A fermi p l o t made of the
shown i n f i g u r e
17.
continuum can be analyzed
familiar
has not been
see how much above background
lies.
11 i s
counting r a t e
from the
i nt o
two
660 kev component and an ot he r b e t a -
spectrum o f low i n t e n s i t y
and a maximum energy of 0.95 ± 0 . 1 5
Mev.
there
from the fermi
plot
a bet a- s pect r um e x i s t s
is
no reason f o r saying t h a t
with a maximum energy of
The discr epancy between t h i s
work and t hat
can be expl ained by n ot i ng t h a t K e i s t e r
with an a c t i v i t y
repor t ed
her e.
a large p a r t
observed.
end- poi nt
of l/5Q or
the
than t h a t
weak, high energy
<Vhat appears to
energy of
of l e i s t e r
et_ a_l.
<Jith such a weak source
oi
i»lev end- poi nt
less
it
683 kev.
used a source
used
is
in
possible th a t
be a component
spectrum with an
683 kev could be t h a t
p o r t i o n of t h e 1
energy
speotrum t h a t meets t h e high
background t h a t
is
from 660 kev to
690 kev.
statisticolly
rate
significant
importance
because t he
in working out
scheme proposed by K e i s t e r eJL a l .
modate a beta t r a n s i t i o n with t h i s
scheme o i
the decay
Cork et_ a l .
energy,
can accommodate
t h e r e ar e o t h e r d i f f i c u l t i e s
present ed
intensity,
greater
i n the
The beta-spectr um wi th a maximum energy of
of
the work
component would not be
655 kev spectrum and produces a counti ng
Mqv i s
et_ a l ■
than
regi on
0.95 ± 0 . 1 5
scheme of
cannot
and,
while
Os^^
accom­
the
such a t r a n s i t i o n ,
by the
latter
scheme.
0.660
2.0
MEV
0 . 9 5 MEV
2 .4
2. 2
{ I + P 2
fig.
17
2. 8
2.6
)2
Fermi P l o t
for
Gs^34
3.0
62
The w r i t e r
feels,
indicates th at
warranted,
therefore,
further
study
that
of
the
the
work r e p o r t e d here
17 A
decay of G s
is
CHAP TAB 7
thb gon7 bbgi j ;;
1•
blsctbgn
gpbgtbuh of
cs 131
Introduoiton:
Barium 131 i s
known to decay to Gs131 by e l e c t r o n
capture with a h a l f - l i f e
various
of approximately
11.5 days.
i n v e s t i g a t o r s ^ -3^ who have studied t h i s
tope have found no evidence
The
radioiso­
i o r p o s i t r o n decay t h a t might
compete with e l e c t r o n capt ure.
hhen Ba^3^ decays to Cs^3^ ,
the product
in one of
states.
nucleus may be l e f t
s e v e r a l exei ted
Gonsi der^-ble work has been done in t h i s
in order to
determine
transitions
that
these
e x ci t e d
occur between them.
work done in t h i s
l aborat ory
in
periormed with s c i n t i l l a t i o n
*1
Yu.
Btates i n Gs
Phys.
investigating th is
spectrometers*
Bev.
1
and the
All of the previous
Gideon and xwurbatov , PhyB.
22S. Kat cof f ,
l abor at or y
The work
Bev.
72., 1160
decay was
7^.,
392
(1947).
23Da l e , Bi o h e r t , Bedfield and Kurbatov, Phys.
BO. 763 (1950).
24
Bimmertnan, Bal e, Thomas and Kurbatov, Phys.
8 0 . 908 (1950).
25B. Kondiah, Ark.
(1C
J 47).
f.
F'ys.
2., 2 95 (1950).
Guffey, Phys.
Bev.
82., 461
Bev.
Bev.
26
W. H.
27B.
Canada and A.
G. Li i t chel l ,
(1951).
63
(1951).
Phys.
Bev.
8j3,
76
64
reported
netio
in
this
s p e c t r o me t e r
o r d e r to
studies
the
i«ios t
expand upon t h e
primarily
of
^ith
decay,
scintillation
coefficients
Pr evi ous
concerned
of t h e
multipolarity
as p o s s i b l e ,
conver ai on
2.
wi th
determine t h e
sitions
whioh i s
confirm and p o s s i b l y
were o b t a i n e d
to
ohapter,
of
was done
results
spectrometers,
a s many of
these
dprk :
of
the
previous
work, done on the
investigators
indicated.
intensities
Al l
IV and V*
1 ^"1
i n Gs
that
decay of
were r e p o r t e d
reported
spectrometers,
88 . 263
t he
E llio tt,
(1952).
Loui si ana
i'or t he
gamma—
ray
the
are
referred
intensities
Goodrich,
Phys.
the
to
that
of
Phys.
Phys.
rtev.
by
Hev.
hev.
9l_, 497
(1953).
(unpublished ) ,
Phys.
Hev.
97_, 139
Phys.
^ev.
101. 149
(1956) .
to
ar e
were determined
Hest er and B r i c e ,
L. A. J e f f r i e s , ti. G. Thes i s
Gtat e U n i v e r s i t y , 1954.
H* <<. Campbell,
by t h e
work done wit h magnetic
^2Lu, Kel ly and ^iedenbeok,
'Z'X
iieggB, Hobinaon and Pi nk,
34
shown t he
v a r i o u s gamma-ray t r a n ­
Gheiig, Haskins and Kurbatov,
Cork, Be Blanc,
(1953).
30
Vv. Payne end K.
31
for
intensities
29
9 1 . 76
IV a r e
The numbers i n p a r e n t h e s e s
reported
497 kev t r a n s i t i o n .
£9
tran­
transitions.
numerous t r a n s i t i o n s
the
and a l s o
by means o f measuring t he h -
In Table
sitions.
in
that
the
i s summarized i n Tables
relative
t h e mag­
be p u b l i s h e d .
(1955).
65
TABLE IV
RETORTED ENERGIES OI’ TRANSITIONS IN Cs131
(LEV)
(A)
MAGNETIC 5P KCTAOLETSA3
Tr an­
s i t i ons Refererioe 25 Reference 27 Reference 28 Reference 29
1
43
55
O
*
5
78__._
65
3
108
92
122
122 (1.3)
122
4
124
153
5
6
196
7
r,06~f2 0 )
8
215
9
241 ^i:L'
£41 fl4)
239
10
242
11
371 (12)
372 (25 J
370 (7)
374
488
12
13
494 (100)
497 (100)
494 TlOO)
497
14
58 5
15
62 0
66
TABLE IV (CONTINUED)
(B)
SCINTILLATION SP_CT.t0i£STER3
Tran­
sition s
1
O
3
4
5
6
7
9
9
10
11
12
13
14
15
16
17
18
Refere noe 30 Reference
31 Reference
83
33 Reference
90
34
( 6*.61
100
f5 7 j
123
(57)
122
(55“)
(44 J
215
240
»
I OXl
£14
(41)
370
(29 )
373
(36)
372
(£9!
500
(100 )
497
(100)
496
(100)
620
(8 )
620
(9)
620
T9.3)
9 0 0 Ta7
1 020 74)
900
lu20
r > c
A
*Va l ues
(4 ) - —
from r e f e r e n c e
917
10 32
’ 123
160
’ 215
240
a250
[Q> 5.6.7
;2a o i .
3,1
£9 used as
J
(73.)
(55)
(10.3)
(365
*4Q_5._ (5.4,
497 (100
588 (3*6;
620 (6^4;
600 10*11
750
918
1039
c a l i b r Mi i o n
(3.1J
points.
67
T/'.JBLE V
itEPuHTEL CONVSi\oIOi; GOEPPICIENTS AMD K / L RATIOS i ' O l i G s 1 3 1
E llio tt
®v
©t_ a l
K/L
Cork, et^ a l
K /L
K /L
6. 0 i 0•5
124
3
0.131
± 0.5
8 ± 0. 6
15
y.o ±
0. 19
3. 3 ± 0. 5
0. 013
£49
374
0.010
497
0.0045
6.0 1 0 ,5
a= 0.013
2 .5 ± 0.0
620
1020
8=0.0008
68
measuring t h e
photoelectrons
interesting
to
not e
intensities
reported
ejected
the g r e a t
lor
disparity
a particular
mined by workers u s i ng magnetic
those
usi ng
scintillation
transition,
tillatio n
55;j to
lor
73/&,
transition
the
increases,
it
is
able
ple,
f o r the
to
whereas
be noted
the
are
is
124 kev
oi
table
interesting
the
that
to n ot e
transitions
are
in
as
reason­
as determined by
In good agreement.
scintillation
I'or exam­
spectrometer
from 28^ to
data y i e l d
from
scintillation
the v a r i o u s
of
scin­
energy of
from the
intensities
intensities
s p e c t r o me t e r
t he
to
u s i ng a magnetic
spectrometers
not
relative
eone wit h
As the
al so
lor
373 kev t r a n s i t i o n ,
36,j,
intensities
of
whereas
Irom 7 , j
2 57S.
In Table Y i s
i n f o r ma t i o n o b t a i n e d
spectrum o f
l i r s t , not
and
to
scintillation
relative
magnetic
1.3/i*.
is
as d e t e r ­
intensities
of
intensities
s p e c t r o me t e r s
data y i e l d
the
with
agreement,
magnetic
lor
between t he magnetic and
reported
determined
relative
It
It
s p e c t r o m e t e r s as opposed
investigations
yield
s p e c t r o me t e r work l e s s e n s .
the
transition
spectrometers.
found a val ue
disagreement
that
between t h e
whereas Canada and I l i t c h e l l ,
spectrometer,
the
example,
s p e c t r o me t e r s
from a r a d i a t o r .
Cs
all
second,
for
.
of
where
same q u a n t i t y ,
example*
1
summarized the
from st udi es’ of
Irom the
the
desired
the
two f a c t s
quantities
disagr eement
215 kev t r a n s i t i o n ,
reported
conv er s i on
have
s e v e r a l measurements a r e
considerable
the
table
previously
can be n o t i c e d ,
been measured,
reported
exists.
Illliott
electron
for
t he
I’o r
et_ a l .
report
a
69
value of
of
0.19,
whereas
ITor t h e
same t r a n s i t i o n ,
of
wh i l e
0.8,
and
Cork
Jeffries,
mat i on and
the
H lliott
et. a l .
a value
Jeffries
of
found
o.3.
d i s a g r e e me n t
et
f in d s a value
a l.
report
a value
This
of
laok
on t h o s e
oan be a t t r i b u t e d .
culty
making a c c u r a t e
measurements on t he
of
activity,
a
of
sour ce
netic
low s p e c i f i c
spectrometer.
r educe
of
the
the
the
error
crystal.
results
-Both o f
Scattering
last
mentioned
values
of
the
ularly
at
relatively
conversion
The d a t a
ther
Ba
1^1
studies
•
with t h e
was not
t he
sour ce
paper,
lation
some of
spectrometer
inconsistencies
in
effects
i n Tabl es
this
magnet i c
tron
the
the
d iffi­
spectrum
from
wit h a mag­
spectro­
correct
scattering
could
would
nlso
out
affect
spectrometer.
tend
to
lower
and K./L r a t i o s ,
the
partic­
the
in
whose
work i s
garni: a - r a y
an e f f o r t
intensities.
sequences
spectrometer
of
t he
studies
spectrum were performed
IV and V show why f u r ­
laboratory
the
i ncl uded
wi t h t h a t
to
resolve
on t he
I n Table
an e f f o r t
in
performed
in
order
conversion
to
IV
obvious
transitions.
Cs
of
n scin til­
the
measurements
decay
reported
spectrum wi th
various
in
on
Campbell a l s o
numerous gamma-gamma c o i n c i d e n c e
determine
to
were
low e n e r g i e s .
were made a t
studied
that
made t o
scintillation
and whose work was done c o n c u r r e n t l y
this
Infor­
scintillation
coefficients
collected
Campbell,
complete
least,
by e l e c t r o n s
in
ratio,
particu larly
provision
introduced
obtained
these
at
Concerning t h e
me t e r work on e l e c t r o n s ,
or
In p a r t
t he
results
obtained
0 . 04 2.
a K/L r a t i o
9 for
of
of
resolve
to
The
elec­
some
70
remaining questions about t he decay of Ba^*'’’^.
3.
Present
rtork;
E a r l i e r magnetic spoctromct'jr s t u d i e s of the
sion
electron
spectrum of
were severely hampered by
the very low s p e c i f i c a c t i v i t y
Barium 131 i s
the
least
stable
of the
sources then a v a i l a b l e .
produoed by an n , y r e a c t i o n on
abundant of
t he
130
Of the
approximately O . l / o i s
This
scarcity
that
Ba13^ has a low cross s e c t i o n f or thermal neut r ons,
make i t
of Ba
1
the 3a
one of
s t a b l e barium i s o t o p e s .
barium found i n n a t u r e ,
of
conver­
difficult
.
isotope,
coupled with the
to o bt ai n high s p e c i f i c
In o r d e r to obt ai n
as p o s s i b l e ,
activity
fact
sources
souroo m a t e r i a l with as high
specific
activity
10 mg of BaOO^ t h a t
enriched
in the Ba^ v i sotope were obtained
had been
from the
Stable
I sot opes Division of the Oak Ridge National Laboratory.
the
barium pr esent
in t h i s
sample was i r r a d i a t e d
sample,
in a thermal neutron
mately 10^^ n/sea/om^ f o r a period
An a n a l y s i s of
i ^n
f l ux of
small amounts of Ca, P e , tig,
Na and or along with
Aince no extensive
was to be done on the
calculations
any o t h e r a c t i v i t i e s
working with the
sample.
sion was reached t h a t
i'rom the
appr oxi ­
carbon and
the various barium i s o t o p e s .
determine i f
This
t he Oak Ridge
i n a d d i t i o n to the
sample,
.
of ten days.
the BaCO^ made a t
National Laboratory showed,
oxygen,
27.5 yo was Ba
Of
might
were made to
cause d i f f i c u l t y
calculations,
no o t h e r a c t i v i t y
chemistry
the
in
concl u­
should cause confu­
sion in the work to be done on the Ba^1^*.
This conclusion
71
was borne o u t , i o r
ments.
However,
spectrometer,
t he most
in the
p u r l , by t h e
first
u s i ng a s t r o n g
weak t r a n s i t i o n s
run
(Fig.
source,
were observed
that
subsequent
18)
experi­
with t h e magnetic
indi oal i ons of
might
several
be caused by o t h e r
e o t i v i t i es.
The i n i t i a l
appr oxi mat el y
added to
the
activity
100 me.
were pr e pa r e d a t
to
their
the
sources f o r
from t h i s
different
t i mes and
figure
t he
from t h i s
system.
In t he
The u n i t s
the
in
details
able.
the
arbitrary
coun t i n g
of
were to
But,
t he
the
10.
dens i t y
current
spectrum
In t h i s
since
in t h i s
rotating
Of t h e v a r i o u s
units,
coil
data
taken
spectrum,
u s i n g the
run
only
rotating
t hrough t h e
field
was determined as a f u n c ­
rate.
this
first
conver si on e l e c t r o n
those p a r t s
Figure
conversi on e l e c t r o n
runs,
The purpose of
complete
shown i n
arbitrary.
1 *51
surface
n conver si on e l e c t r o n
f i g u r e were o b t a i ne d
subsequent
measured
t i o n of
Cs
sour ces
I was 1/8'* wide and
a r e given as v o l t a g e s
are
of the
shown i n t h i s
In
is
spectro­
A number of
The average
measurements were made with
study
coil.
coil,
source
t he a b s c i s s a s
field
that
/
P
0.1 mg/cm .
wat er was
were numbered a c c o r d i n g
Bourse
1 l/Q" high and was uncovered.
obtained
BaCO^ was
t he magnetio
solution.
chronologioul o r d e r .
was approximat ely
10 mg of
-a. small amount of d i s t i l l e d
BaCO^ and t he
meter were prepar ed
of
spectrum.
spectrum t h a t
be r epeat ed
because of
the
run was to
if
to
In
survey
the
subsequent
showed c e r t a i n
runs
interesting
do so was deemed p r o f i t ­
considerable
l e ng t h
of
time
3
10
K 124
K 1040
A
K 915
K830
L +M
1040
K 215
_L
_L
M124
7 000
8000
9000
K 497
K 373
L 215
COUNTS/SECOND
K249
L+M
49 7
*
L+M
373
L-t-M
239 & 249
K 620
L+ M
K 585 585
L 405
OR
TK435
K 290
L+M
2000
30 0 0
VOLTAGE
■I
F ig.
18
Cs
4000
(ARBITRARY
5000
60 0 0
UNITS)
r r -*i
C onversion
72
K lectron
spectrum
(Source
I)
73
required
life
to
colleat
of
study
the most
Cinoe t h e
the
gies
mean t h a t
since
t han
limited
r e g i o n s of
facts
should
This
such t r a n s i t i o n s
a number of
of
indication
124 kev.
short
t he
the
spectrum.
do not
invectigators
source,
To b egi n w i t h ,
transitions
is* not
not hi ng
spectrum shown i n
be n ot ed.
of
to
be
exist.
with
have observed
is
t he
off
t lie d e t e c t o r
falls
do,
such t r a n s i ­
were not
of
to
They probabl y
The main r eas on why such t r a n s i t i o n s
efficiency
ener­
interpreted
tions.
that
hall-
t he more d e t a i l e d
t h i c k e r than d e s ir e d ,
details
give no c l e a r
less
relatively
by making a now and s t r o n g e r
, a number oi
data
souroe
souroe was a l r e a d y
be gained
11
and the
significant
Concerning t he
Fig,
data
decay of t he
to
could
the
seen
rapidly
below 100 kev.
The conver si on peaks
the
1£4,
in t h i s
215,
for
runs
weaker
the
al.
were a l s o
in
clearly
is
subsequent
two t r a n s i t i o n s
That
seen.
were a l s o
confirmed
by t he
a
In subsequent
were a l s o
observed.
since
exist
was
In some p r e v i o u s
were r e p o r t e d a s one.
for
only
Con­
249 kev t r a n s i t i o n s
two t r a n s i t i o n s
e x per i men t s .
observed
such a t r a n s i t i o n .
£39 and
i.e.,
The h. peak
some importance
reported
c o r r e s pondi ng to
obser ved.
transition
of
were a l l
Conversion per ks
were a l s o
for this
transition
obs e r v e d.
transitions
is
had p r e v i o u s l y
v e r s i o n peaks
spectrum.
transitions
t he 1 and id peaks
Confirming t h i s
also
run of
a 133 kev t r a n s i t i o n
Cork et
the main t r a n s i t i o n s ,
.573 and 497 kev t r a n s i t i o n s ,
initial
number oi
for
The
515 end
shown
work t he s e
6£Q kev
conver si on peaks
74
shown.
ol
The 650 kev t r a n s i t i o n had been r e p o r t e d
prior
ously
investigations.
The 535 Icev t r a n s i t i o n was p r e v i ­
r eport ed only by Cork et_ aJL. and Campbell.
highest
energy t r a n s i t i o n s ,
all
or
some of
produced h-couver sio 11 peaks t h a t
order
to more e a s i l y
di s cri mi nal or
tor
observe
s e t t i n g of
was, i ncr eased
until
from 1 count/'sec to
The t h r e e
which had p r e v i ­
ously been observed only with s c i n t i l l a t i o n
also
i n a number
s p e c t r o me t e r s ,
were o b s e r v a b l e .
the h i g h e s t
energy peaks,
used ’with the
detec­
the background
counting r a t e
dropped
The i n d i c a t e d
are
in which the
was measured as a f u n c t i o n of
350,
The e n e r g i e s
determined
915 and 1040 kev.
In a d d i t i o n to
data
f o r t hes e
The u n c e r t a i n t y
the t r a n s i t i o n s
iihow two more weak t r a n s i t i o n s
and 405 o r 435 kev,
fcyo.
those determined
energies
of t h e s e t r a n s i t i o n s
rate.
The data
obt ained
t he
shown are
on t h e s e
the
the a m p l i f i e r
0. 3 c o u n t / s e c .
current
In
uncertainty
all
of
transitions.
i n subsequent
counting
transitions
in
runs
were
t hes e val ues i s
discussed
above,
whose e n e r g i e s
i n t hes e
are
e n e r gi e s
the i nf o r mat i on t h a t
As p r e v i o u s l y
the
590
being
was
stated,
it
is
not
c e r t a i n whether t hes e t r n s i t i o n s a r e involved in the
1
decay of Csx
, s i n c e the data on them are quit e sket chy.
In a d d i t i o n to t h e
data obt ei ned
lor
i nf or mat i on on t h e s e
-Fig. 13 and t h a t
from some subsequent
give
some i n d i c a t i o n of weak t r a n s i t i o n s
490,
630 and 750 kev.
sitions
of
t he s e
These
energies
facts
t r a n s i t i o n s , t he
at
roughly
90,
are mentioned s i nce
have been r e p o r t e d .
runs
160,
tran­
75
A f t e r making the
spectrum shown in I’ig .
made over
pared
18,
certain parts
s our ces .
initial
a number of
)i
In t h e s e
the
areas
under the
t he data obt ai ned
subsequent
results
oi
the
shown a r e p e a t
from source
right
into
the
A peak of the
the A peaks of
L peak of t he
i f pure
that
axis
that
j^I so
from source V.
covered.
amount
in t h i s
of
to n o t i c e
, t he
the
is
run
t he
1.
complexity to
is
the
resol ved
and
the
This
appears
exaggerated
In s i z e
of
the
the
was qui t e
being approximately
is
relative
to get
to
the
It
wherethe
of t he
wide
thick,
£ mg/on^.
evident.
figures
lower p a r t
spectrum was run i n o r d e r
the A/ (L + i.x) r a t i o s
source
end i n o t h e r
that
too spectrum i n d i c a t e d
The source was l / 8 "
scattering
l o g a r i t h mi c
attempt
lecture
part
spo d r u m wee
months a l t e r
the port.ion of
Is
This
This
lowenergy
£15 kev t r a n s i t i o n
surlace density
A c o ns i d e r a bl e
of t he
159 and £49 kev t r a n s i t i o n s
£0 shows
and 1 l / Q M high and
realised
the
showning t y p i c a l
‘ 15 kev t r a n s i t i o n *
was obt ained
the average
One added
home of
19 through £4.
spool rum.
153 kev t r a n s i t i o n .
of the
runs
I one and a h a l f
18.
of t he
could be made.
In Tig.
shown in 1’i gur e
peak of
peaks
subsequent
electron
runs were
so that- b e t t e r measures of
in T'igures
L9 i s
subsequent
runs the p o i n t s
are p re s ent ed
conversion
obt ai ned
conversion
in t hes e
electron
spectrum using v a r i o u s p r e ­
spectrum were t aken more c l o s e l y
t he
survey of the
is
spectrum
hi gher p a r t s .
a better
source to
be
vertical
e s t i ma t e
373 and 497 kev t r a n s i t i o n s .
was also made to use t h i s
to
of
An
produce photo-
COUNTS/SECOND
124
IO
K 2 39
K 249
M 215
L 133
700
900
CURRENT
iig.
19
Partial
Os
I IOO
(ARBITRARY
Conversion
76
electron
UNITS)
opecstrum
(Source
I)
2
O
49 7
COUNTS/SECOND
K 373
IO
L+M
L+M
CURRENT
Pip;.
20
I800
1600
1400
P artial
497
373
(ARBITRARY
C onversion
77
E lectron
UNITS)
dpectrum
(Oouroe
V)
78
electrons
from a Pb r a d i a t o r .
insufficient
to
The a c t i v i t y ,
however,
produce enough photo e l e c t r o n s
was
to make r e l i ­
ab l e measurements.
spectra
In Pi gs .
21 and 22 ar e
obt ained
from source
shown conversion e l e c t r o n
III.
This
wide and 3/4" high and was uncovered.
density
of t h i s
centimeter.
is
to
source was only
It
is
be observed.
There appears to
the
to be noted
s i o n peak,
kev.
t he
There i s
which,
if
that
be a weak peak to
If
The average
very
this
is
little
are to
the
left
of
what appears
results
agreement
with those of Campbell.
from source
a small amount of
t he
studies.
effect
1" high.
of
Cs
IV.
137
standard
used
This s p i k i n g was done as a f u r t h e r
.source IV was l / 8 "
in
check on
wide 'nd
s u r f ace d e n s i t y of the source was
p
0.01 mg/cm .
Ho new f e a t u r e s were observed i n
spectrum o b t a i n e d .
belong,
source was spiked with
comparison
source geometry.
the
shown conversion s p e c t r a
This
, t he
would bri ng
to
The average
approximately
the
interpretations
23 and 24 ar e
94
corresponds
These
In Pi gs .
is
to be an ot he r weak peak
158 kev.
these
t h e X peak of
t aken to be an fi-conver-
an energy of
obt ai ned
scattering
energy of t h e corresponding t r a n s i t i o n
also
square
be observed.
consi dered as an 1-conver si on peak,
i nt o
s u r f ace
s e v e r a l micrograms per
Two new f e a t u r e s
135 kev t r a n s i t i o n .
source was 3/lG"
of
cour se,
All of
scintillation
the
The conversion peaks
shown in Pi g.
to Bal37.
sour ces used were also
spect r omet er it; order
s t u di e d with t h e
to make the necessary
24
COUMTS'SECOND
120
eo
40
650
Pig*
21
P artial
eoo
700
750
CURRENT
(ARBITRARY
Os
C onversion
79
E lectron
650
900
UNITS)
bpeotrum
(source
III)
COUNTS/SECOND
30
20
497
K 249
M 2 15
K 2 39,
L+M
497
H 50^S450
1050
CURRENT
ii'iC-
2?
P artial
Cs131
1900
(A R B IT R A R Y
C onversion
80
E lectron
UNITS)
Spectrum
(Source
III)
T
12
COUNTS/SECOND
K 124
8
L
124
K 2(3
660
——
740
700
'Sl>‘
CURRENT
P ig.
2.3
P artial
Gs
"1
B20
J__ L
860
(ARBITRARY
C onversion
81
' >
1040
1080
UNITS)
E lectron
Spectrum
(Source
IV)
K 661
COUNTS/SECOND
30
20
L + M 661
CURRENT
Pig.
24
2330
2290
2250
(ARBITRARY
UNITS)
iv and L + l.L Conversion Peaks of
82
2370
(Source 17)
83
measurements l o r
calculating
the
conversion c o e f f i c i e n t s
t he manner p r e v i o u s l y
described.
c o n j u n c t i o n with the
sources t h a t
one from which the
The Gs
exist
for
result
the t r a n s i t i o n s
the 830 kev a n d
from the
exists
results
t i o n of
i n t he
from the
nation i s
c onver t ed.
the
for t h i s
XI the
intensity
t he n the
the
intensity
because of
the gamma-ray spectrum.
that
is
probably
d ot er mi the
posi­
The 115
however,
rather
t r s n s , i t ion s.hould be reasonably
measurements ar e
differences
theoretical
A possible
r ecent
conversi on t h a t
work repor t ed
accurate
between t he
ones
assignments ar e d i f f i c u l t
some very
the
si nce
it
highly
Both conversion e l e c t r o n and gamma-ray i n t e n ­
sities
a^ and
gamma-ray
and
be
The ambiguity
the
transitions
to
intensity
139 kev t r a n s i t i o n
p r e s e n t s an ot he r problem,
principal
is
probably
the
to make a c c u r a t e l y
t he photopeak in
one of
2 0 ,0 ,
that
it
The a mb i g u i t i e s
i n making a c c u r a t e
case of
measure­
iB made f o r
weak conversion l i n e s .
fact
uifficult
lev t r a n s i t i o n
is
table
1040 kev t r a n s i t i o n s
difficulty
measurements on t h e
that
8 was o b t a i n e d .
i'rom t he
studied.
in
spiked was the
a d e f i n i t e multi pole assignment
ma j o r i t y of
source used
from the var i ous
summarised in Table VI.
noted t h a t
were not
spectrum shown i n i ’ig»
The i nf or mat i on obtained
ments i s
137
in
to
f or
to
w i t h i n about
experimental
the only
possible
values
suggest ed,
developments on the theory
were publi shed a f t e r t he
Bose et
a 1.
however,
of
of
rultlpole
explain.
e x pl a n a t i o n i s
in t h i s paper.
accurate.
by
internal
completion of
t he
in c a l c u l a t i n g
84
TABL‘D 71
OUUUAKY OP Gs131 DATA
f -day
i in e r o
fkevj
A &/or L
Kelati ve
Intensity
*124
L:
290 ± 20
*133
A:
25 ±5
*215
A: loo
A;
10 ± 1
average
a x 10*3
150 ± 10
3 .2 1 .3 7.6
3.2
7.7
7.6
6 . 5 1 1 3. 3
5.3
8.0
7.8
5.1
L
>*2
36 ± 10
-5
L:
2.0 ± . 6
7.5 ± 2
*249
L;
2. J i • 6
7.5 12
*373
A:
17.2±.5
A: 30.1 ± . 5
Theoretical
Multipole
K /L
a x 10*3 Assignment
68 ± 15
*239
*497
K/L
17 ± 2
10.51 1
"*3.5
-7.5
7.8
6.2
6. 1
7.9
6.7
7. 2
*56 5
A:
0.5G±.10
5.8 1 1.5
*620
A: 0.471.15
2.8 ± 1.2
------------- —
950
A:
915
A: 0.08-*02
1.6 —• 6
1040
A: u.14±.03
1.7 ± .5
0.035±
.015
1 .7 ± .8
Values from r ef er ence
spect r omet er.
Ml
£2
El
Ml
E2
M2
Ml
22
El
Ml
E2
M2
Ml
E2
Ml
E2
Ml
£2
£1
Ml
E2
M2
Ml
E2
El
E2
El
Ml
E2
Ml
E2
Ml
E2
59
195
E2 + Ml
E2 ♦ Ml
102
108
E2 &/ o r Ml
75
75
E2 i / o r Ml
9.4
14
8.2
12
25
20
Ml
E2
11.7
9. 7
7" -*
L
.m
*H
i.
8.0
5. 7
E2
1.8
4.9
O94
3.5
7. 4
2.7
1.85
2.0
1.3
El
>r Ei.
E2
E2 A/or Ml
29 used in c a l i b r a t i n g
85
t h e i r t a b l e of
tio n that
conversion c o e f f i c i e n t s have made tho assump­
the nucleus
v i r t u a l photons.
can be t r e a t e d
r i eoent l j ,
however.
hf ve re-examined
the consequences of
into
finite
the
account
the
charges and c u r r e nt s
throughout the nucleus.
is
s i ze of
that
values
as
as
for
20,0
tions
the
or d ecr eases ,
In s p i t e of
et
a 1. *s values
of t hes e
uniformly
calculations
at
C = 55 and
that
d e vi a t i on s
These d e vi a t i on s
as l ar ge
can be e i t h e r
depending upon the p a r t i c u l a r
in Csx^
that
apparent ly
the
transi -
exists
would be explained
if
f or
the
arc
from the c a l c u l a t i o n s of nose e t
faot
can e x i s t ,
that
d e vi a t i on s
£0,.*
a 1.
from --tose
was ustially p o s s i b l e to make
1 '~-i
mul t i pol e assignments f or the t r a n s i t i o n s in Cs
definite
since the maximum p os s i b l e
coefficients
estimated
35
it
d e v i a t i o n s of the
are approximately
experimental e r r o r s .
of such d e v i a t i o n s ,
(1956).
aasumpt i o n , t aki ng
values l o r the h-oonversion c o e f f i c i e n t s
smaller than the values
rz c
Church and ..eneser have estimated
The discrepancy
215 kev t r a n s i t i o n
theoretical
this
convert, ion c o e f f i c i e n t s
can sometimes r e s u l t .
involved.
«<eneser
can occur from nose et_ a l . 1s
= 55 and 1*11 t r a n s i t i o n s
i ncr eases
Church and
the nucleus and consi der i ng
One r e s u l t
even lower atomic numbers.
that
source of
being d i s t r i b u t e d
observable d e v i a t i o n s
f or various
as a poi nt
il.
L.
however,
Church and J.
equal
to or
Because of
conversion
l e s s than the
the p o s s i b i l i t y
when a p a r t i c u l a r
<Jeneser, f h y s .
transition
dev.
104. 1382
86
is
apparent ly mixed no attempt
was made to
percentages of tho mul t i pol e or der s
st ances
such c a l c u l a t i o n s
calculate
si nce under the
seem u n r e a l i s t i c .
the
circum­
SELECTED BIBLIOGIIATHY
L.
W
, Campbell , to
E* L.
Churoh and J .
Cork,
Le Bl anc,
Craves,
be p u b l i s h e d .
Weneser, Phys.
Keater and B r i c e ,
Danger and Moff at ,
L eister,
Lee and
Schmidt,
Phys.
Phys.
Lev.
Phys.
Lev.
Kev.
104. 1382
Lev.
88.
97.,
344
451
(1956).
91_, 76
(1953).
(1952).
(1955).
L. M. Longer and B. C. P r i c e , Phys. Lev. J76, 641 (1949);
L. M, Langer and L. J . Mof fat , i b i d . 8 2 . 635 (1951).
C,
L. Peacock and A,
M.
E,
E.
P.
C.
Mitchell,
Phys.
Lev.
7 5 . 1272
(1949).
Lose, Appendix IT, Be t a - and Camma-Hay S p e c t r o s c o p y .
I n t e r s c i e n c e P u b l l s h e r s , I n c . " Lew York, 1955.
Siegbahn and II. Svartholm, Nature 157 . 372 (1946);
N. Svartholm and L. Siegbahn, Ark. Mat. 1'ys. A5 3 .
No. 21 (1946).
S h u l l and D. Dennison,
N.
Svartholm,
M.
A.
Ark. f .
Phys.
i?ys.
Waggoner, Phys.
Lev.
£.,
hev • 7 1 . 681;
No.
8£_,
14,
806
115
72. 2 56
(1947).
(1949).
(1951).
(JENELAL LIABLE 1JCOS
J.
<V
. B l a t t and V. P. ^ e i s s k o p f , Theo r e t lea 1 Nuclear Phy si c s .
John Wiley & s ons , I n c . , Ne v , 4/ c rk , 1952 .
L.
D.
L.
Si egbahn, B e t a - and Camma-Lay Speotro noopy. I n t e r e c i e n c e
P u b l i s h e r s , I n c . , New York, 1955.
Evans, The ^tomi o Nucl eus . MoSraw-Hi11 Book Co. , I n c . ,
New Yo rk , 1955.
87
VITA
Loon otanley August was born in Hew Orleans,
Loui si ana,
t h e _e,
In 19£6.
graduat i ng
He at t ended grammar and high school
irom St .
Aloysius High School In 1944.
In i ot ober of
1944 he was c a l l e d
Uni
Unval neeerve and served u n t i l August,
ed S t a t e s
whe
i
In
jeptember of
and
1946 he entered Louisiana
received h i s
B.
ane Uni ver si t y
of 195&.
S.
degree in Physics
if
tie
and received
In June of
He. Orl eans,
j
1946
he was honorably discharged as a Yeoman Third J l a s a .
In September of 1950 he entered
th
to a c t i v e duty i n the
In 1'ebruary of
Graduate school of Louisiana
Department oi
In June of 1950.
the Graduate
h i s 91, 0,
Universit y
uohool of
degree
in June
1955 he married Lorraine Donnelly of
Louisiana.
now a candidate
^tate
otate
1953 he entered
Un i v e r s i t y ,
end he
for the Doctor of Philosophy degree in
Physi cs.
86
E X A M IN A TIO N A N D T H E SIS REPORT
l e a n
C and idate:
* u t*- y
~^ « J ^ * f ~
Ay s / r J
M ajor Field:
I
T il lo o f T h esis:
T~A e
E } e c \ r 0 h-
„
^ p ** <-
/>(3 V
^ h
<2 * ^
fD
13 1
Approved:
M ajo r P ro fesso r and C h a irm a n
\/a
P e n n o f tJje’T ^ r m u n t e S ch oo l
E X A M IN IN G COM M ITTEE:
i
/
\
&
Q
\ ?
L—
D a te of E x am in ation :
: ~Tt
j;
/h i
/