Bratislava 09 September 2009 – ICRM2009
1
Alpha-particle emission probabilities
in the decay of 240Pu
G. Sibbens, S. Pommé, T. Altzitzoglou, E. García-Toraño, H. Janßen,
R. Dersch, O. Ott, A. Martín Sánchez, M.P. Rubio Montero, M. Loidl,
N. Coron, P. de Marcillac, T.M. Semkow
IRMM - Institute for Reference Materials and Measurements
Geel - Belgium
http://irmm.jrc.ec.europa.eu/
http://www.jrc.ec.europa.eu/
Decay scheme 240Pu
Bratislava 09 September 2009 – ICRM2009
2
Alpha-particle emission probabilities and
energies in the decay of 240Pu incorrect?
Bratislava 09 September 2009 – ICRM2009
105
240Pu
239Pu
104
counts
3
239Pu
240Pu
α1
α2
Bortels, G., Verbruggen, A., Sibbens, G.,
Altzitzoglou, T.,1996.
EUROMET Project No 325: Analysis of
Plutonium Alpha-Particle Spectra.
IRMM Internal Report GE/R/RN/01/96.
103
239Pu
102
239Pu
101
100
5.04
5.07
5.10
5.13
5.16
Energy (MeV)
Sibbens G., Pommé S. Study of alpha-particle emission probabilities and
energies in the decay of 240Pu. Appl. Radiat. Isot. 60 (2004) 155-158.
EUROMET project 749
Bratislava 09 September 2009 – ICRM2009
Alpha-particle emission probabilities
in the decay of 240Pu
IRMM (co-ordinator), CIEMAT, PTB, Univ. of Extremadura,
LNE/CEA-LIST, CNRS, NYSDOH
Project : experimental investigation by alpha-particle spectrometry
and a re-measurement of the alpha decay data of 240Pu
Deliverables : a new set of alpha-particle emission probabilities,
also for the less intense peaks
4
EUROMET project 749
Bratislava 09 September 2009 – ICRM2009
¾ Preparation of thin 240Pu sources
¾ Alpha-particle spectrometry
¾ Spectral analysis
¾ New set of measured alpha-particle emission
probabilities for 240Pu
5
240Pu
material
Bratislava 09 September 2009 – ICRM2009
6
Solution: 1.4 g 20 MBq/g Pu-240
in 1M HNO3
isotopes
Pu-240
Pu-238
Pu-239
Pu-241
Pu-242
mass %
99.83
0.002
0.102
0.0560
0.0100
α-activity %
99.82
0.151
0.028
0.0006
0.0002
Sibbens, G., Altzitzoglou, T., Benedik, L., Pommé, S., Van Ammel, R., 2008.
α-particle and γ-ray spectrometry of a plutonium solution for impurity
determination, Appl. Radiat. Isot. 66, 813-818.
source preparation – spectrometry – spectral analysis – new set of Pα
240Pu
sources
Bratislava 09 September 2009 – ICRM2009
7
Pu-240 sources prepared by vacuum evaporation
Substrate:
material: quartz
diameter: 20 mm
thickness: 1 mm
Sources:
activity: 7.5 – 30 kBq
active diameter: 9 and 12 mm
thickness: 3 µg/cm2
source preparation – spectrometry – spectral analysis – new set of Pα
Vacuum evaporation system at IRMM
Bratislava 09 September 2009 – ICRM2009
source preparation – spectrometry – spectral analysis – new set of Pα
8
Quality check 240Pu sources
Bratislava 09 September 2009 – ICRM2009
microscope:
material distribution
9
autoradiograph:
radioactivity distribution
source preparation – spectrometry – spectral analysis – new set of Pα
α-particle spectrometry
Bratislava 09 September 2009 – ICRM2009
10
7
240
Pu
6
10
impurities
(normalised) number of counts
10
5
10
4
10
LNE-LNHB Bolometer
3
10
2
10
2
IRMM 50 mm
2
IRMM 150 mm
2
CIEMAT 50 mm
2
PTB 600 mm
1
10
4.0
4.5
5.0
5.5
Energy in MeV
source preparation – spectrometry – spectral analysis – new set of Pα
Characteristics of 240Pu spectra
Bratislava 09 September 2009 – ICRM2009
11
nr
name
detector
area in
mm2
1
2
3
4
5
6
7
IRMM HR01
CIEMAT sum21
CIEMAT sum0106
CIEMAT sum1006
CIEMAT sum0326
PTB spectrum
IRMM HE01
50
25
50
50
100
600
150
Ω/4π
#events
FWHM
in keV
tailing
0.08 %
0.5 %
0.5 %
0.5 %
1.3 %
0.47 %
2.2 %
3.6×108
3.3×108
4.3×108
1.0×109
1.7×109
3.4×108
1.7×1010
10.5
11.2
11.2
13.1
14.1
21
16.6
3×10-5
6×10-5
1×10-4
2×10-4
1×10-4
1×10-5
1×10-5
source preparation – spectrometry – spectral analysis – new set of Pα
α-particle spectrometry
Bratislava 09 September 2009 – ICRM2009
Pu240 IRMM HE01
150 mm2 PIPS
300 days
12
α1α0
1.E+10
counts
1.E+08
1.E+06
αα8 7
α5 α4
α3
α2
1.E+04
1.E+02
1.E+00
4200
4400
4600
4800
5000
5200
Chechev, 2004
energy (keV)
7.E+03
α5
α4
241+242
1.E+06
counts
counts
6.E+03
5.E+03
α8 α7
1.E+05
Pu
α3
1.E+04
4.E+03
3.E+03
4200
α2
1.E+07
4300
4400
4500
energy (keV)
4600
4700
4800
1.E+03
4800
4900
5000
5100
5200
energy (keV)
source preparation – spectrometry – spectral analysis – new set of Pα
5300
γ-ray spectrometry
Bratislava 09 September 2009 – ICRM2009
γ1
HPGe-detector 36% relative efficiency for 60Co
γ2
1.E+08
1.E+07
γ3
1.E+06
counts
13
Pu-240
1.E+05
γ6
γ4
1.E+04
γ7
1.E+03
1.E+02
1.E+01
0
100
200
300
400
500
600
700
800
900
1000
energy (keV)
source preparation – spectrometry – spectral analysis – new set of Pα
Spectral deconvolution algorithms
Bratislava 09 September 2009 – ICRM2009
14
lab
code
peak shape
IRMM
ALPHA
Gaussian with 3 exponentials at low-energy side
CIEMAT
ALPACA
two-branch line shape
PTB
Fit9
2 exp. low-energy, 1 exp. high-energy tailing and step function
UNEX
FITBOR
Gaussian with 3 exponentials at low-energy side
NYSDOH
GAPQ
generalised exponent for alpha peak and generalised
power function for the left tail
source preparation – spectrometry – spectral analysis – new set of Pα
Fitted peaks
Bratislava 09 September 2009 – ICRM2009
15
Spectrum:
IRMM HR01
Analysis code:
CIEMAT ALPACA
Sum21_4
IRMM HR01
Spectrum:
CIEMAT sum21
Analysis code:
CIEMAT ALPACA
source preparation – spectrometry – spectral analysis – new set of Pα
Fitted peaks
residuals
Bratislava 09 September 2009 – ICRM2009
16
15
0
-15
α0
α45
7
10
Spectrum:
CIEMAT sum21
Analysis code:
IRMM ALPHA
6
number of counts
10
5
10
α149
4
10
3
10
2
10
1
10
6800
6850
6900
6950
7000
7050
7100
7150
spectrum channel
source preparation – spectrometry – spectral analysis – new set of Pα
Impurities in the 240Pu material
Bratislava 09 September 2009 – ICRM2009
17
Gaussian shaped peaks
1.E+12
Pu-240
Pu-239
Pu-241
Pu-242
1.E+08
1.E+06
1.E+04
1.E+02
1.E+00
4200
mass %
α-activity %
Pu-240
99.83
99.82
Pu-238
0.002
0.151
Pu-239
0.102
0.028
Pu-241
0.0560
0.0006
Pu-242
0.0100
0.0002
1.E+06
number of counts
number of counts
1.E+10
isotopes
4300
4400
4500
4600
4700
4800
Energy in keV
4900
5000
5100
5200
1.E+04
1.E+02
1.E+00
4800
4820
4840
4860
4880
Energy in keV
source preparation – spectrometry – spectral analysis – new set of Pα
4900
4920
4940
Coincidence summing effects
Bratislava 09 September 2009 – ICRM2009
18
γ4,3
γ3,2
γ2,1
γ1,0
αT
0.610
1.79
11.24
604
source preparation – spectrometry – spectral analysis – new set of Pα
Independent fit of tailing
Bratislava 09 September 2009 – ICRM2009
6000
19
100000
α688
240
spectrum
241,242
240
Pu
Pu
Pu
5000
number of counts
number of counts
5500
α522
4500
spectrum
residuals
300
10000
α310
6000
residuals
4000
150
2000
0
0
-150
4450
4500
4550
4600
4650
4700
4820
4840
4860
4880
Energy in keV
Energy in keV
Spectrum: IRMM HE01
source preparation – spectrometry – spectral analysis – new set of Pα
4900
4920
4940
New set of Pα for 240Pu
Bratislava 09 September 2009 – ICRM2009
branch
α688
20
DDEP 2008
Chechev
(2004)
Pα in %
Eα in keV
4492.00
0.0000193 (4)
α522
4654.60
0.000047 (5)
α310
α149
α45
α0
4863.51
50.21.15
5123.64
5168.13
0.001082 (18)
0.0863 (18)
27.16 (11)
72.74 (11)
this work
Pα in %
⎧0.000040 (10)
⎨
⎩0.000032 (5) *
⎧ < 10 -5
⎨
-6
1.72(7)
10
*
⎩
0.00097a (9)
0.085 (4)
27.21 (7)
72.70 (7)
* result obtained by γ-ray spectrometry
a
measured fraction was corrected for interfering 241Pu and 242Pu peaks and for estimated summing-out effects
source preparation – spectrometry – spectral analysis – new set of Pα