Muonic Atom of Unstable Nuclei
Patrick Strasser
Muon Science Laboratory
KEK
Collaborators:
K. Nagamine
T. Matsuzaki, K. Ishida, Y. Matsuda, M. Iwasaki
(KEK)
(RIKEN)
New Ion Source:
A. Taniguchi
S. Ichikawa
H. Miyatake
(Kyoto)
(JAERI)
(KEK)
Workshop on Physics with Ultra Slow Antiprotons
RIKEN, March 14-16, 2005.
Introduction
X Physics Motivation
X-RAY SPECTROSCOPY of MUONIC ATOMS !
· Precision tool to measure the NUCLEAR
CHARGE DISTRIBUTION.
· Usefully complement the knowledge
obtained from electron scattering and
laser spectroscopy.
· Successfully used since more than 30
years to study STABLE ISOTOPES in
condensed or gaseous states !
Nuclear Charge Radii of Tin Isotopes
from Muonic Atoms
C. Piller et al., Phys. Rev. C 42 (1990) 182,
L.A. Schaller Z. Phys. C 56 (1992) S48.
(Fribourg Univ. / Mainz Univ.; Exp. PSI µE1)
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Towards Radioactive Muonic Atoms ?
X Facilities with both RI BEAM PROJECTS and negative muon beams:
RAMA WORKSHOP
· TRIUMF (ISAC), J-PARC (E-arena), ...
· RIKEN (RI Beam Factory) if intense µ¯ can be produced,
· and maybe at a NEUTRINO FACTORY PROJECT
X In the near Future
1012 µ/s, 55MeV/c
· MUON BEAM of significant higher flux (PRISM,),
· NEXT GENERATION of RNB facility
X Experimental Methods using muons
· Merging Beams Scenario (M. Lindros, CERN) ,
· Combined Cyclotron Trap & Penning Trap,
· SOLID HYDROGEN & MUON TRANSFER
X Other Methods for Unstable Nuclei
PRESENT: Optical Laser Spectroscopy (ISOLDE, RIKEN, …)
FUTURE: Electron Scattering with e¯ & RI collider Rings
(GSI , MUSES at RIKEN, …)
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Why Radioactive Muonic Atoms ?
X Probing Nuclear Charge Distribution
Matter distribution deduced from measured interaction cross sections. Charge
distribution needed to get information on proton and neutron distributions in nuclei.
· X-RAY SPECTROSCOPY of RADIOACTIVE MUONIC ATOMS !
X Deformation Properties
Quadrupole hyperfine spitting of muonic X-rays yield precise and reliable absolute
quadrupole moment values. Measure the deformation properties of nuclei.
· IMPORTANT ROLE in ESTABLISHING and REFINING NUCLEAR STRUCTURE MODELS !
A
Z
X Muon Capture
X N + µ − → Z −A1 X N +1 + ν µ
Tools to explore changes in collective excitation modes of neutron-rich nuclei.
Kolbe et al., Eur. Phys. J A 11 (2001) 39; T. Nilsson et al., Nucl. Phys. A 746 (2004) 513c
· IMPORTANT ASTROPHYSICAL IMPLICATIONS !
X Novel nuclear structure effects may exist far off the valley of stability ?
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Technical Feasibility
X How to produce such exotic µA* atoms ?
We propose:
· SOLID HYDROGEN FILM used to stop both simultaneously
µ¯ and A* beams.
· µA* ATOMS formed through MUON TRANSFER REACTION
to higher Z nuclei, i.e.,
µH + Az* → µAz* + H
Basic Concept
with
A*
TRANSFER RATE:
λz ≈ Cz Z 1010 s-1
µ−
dµ
A* Ion
Beam
HIGH TRANSFER RATE & HIGH EFFICIENCY
e.g., Z = 50 and
16
3
Cz = 1 ppm (5 × 10 nuclei/cm )
5
-1
λz ≈ 5 × 10 s
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA*
Muon
Beam
X-Rays
D2
µA* Technical Feasibility (2)
X Basic Concept: Two-Layer Arrangement
Ramsauer-Townsend
Effect
Ion Stopping
Region
dµ
µ−
Muon
Beam
pµ
µA*
dµ
H2/D2
(~ 1 mm , Cd ≈ 10-3)
Cold Foil
Slowpbar, RIKEN March 16, 2005 – P. Strasser
A* Ion
Beam
D2
(~ 5 µm)
X-Rays
X Transfer Yield Estimation
(Two-Layer Arrangement)
No dµ atom loss !
dµ
µ−
pµ
YX =
φ λZ
Y µ ¯ Y dµ
λ0 + φ λZ
10 −1
with λ Z ≈ CZ Z × 10 s ,
CZ = N Z N D ,
µA*
dµ
H2 / D2
D2
X-Rays
Transfer Yield per inc. µ¯
Preliminary Transfer Yield Estimation
Yµ ¯ ≅ 0.1, Ydµ ≅ 0.04
µ¯ Stopping
dµ Emission
10- 1
Two-Layer Arrangement
10- 2
(1-mm H2 /D2 ⊕ 5-µm D2 )
10- 3
10- 4
1-mm D2 Layer
10- 5
1-mm H2 Layer
10- 6 1 2
10
101 3 101 4 101 5 101 6 101 7 101 8 101 9
Z NZ [1/cm2]
X Preliminary Yield Estimation for Tin (Z=50):
Q Muon Intensity (1 cm2, 30 MeV/c):
1 × 108 [s-1]
Q Implanted Sn Ions (1 cm2, uniform):
1 × 1012
Q Transfer Yield per incident µ¯:
2 × 10-4
Q Muonic Tin Atoms Formed:
Q Total X-Ray Number Detected:
Two-Layer
Arrangement
21st Century Muon Beam
SHC confinement Field
1-mm D2
2 × 10-5
20’000 [s-1]
2’000 [s-1]
500 [hr-1]
50 [hr-1]
Assuming for µSn 2p→1s X-ray detection (~3.4 MeV) : b.r. ~ 0.7, ε ~ 0.005 and ∆Ω ~ 0.002.
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Practical Considerations
X SIMULTANEOUS implantation of unstable nuclei and measurement with µ¯.
X Ion beam ENERGY and SPREAD determine the implantation DEPTH and THICKNESS.
Ion range in solid hydrogen: 1 mm ¹ ~ 10 MeV/u
5 µm ¹ ~ 30 keV/u
SWEEPING Beam Energy
X CONTINUOUS SPUTTERING of solid hydrogen films.
If proven important,
Hydrogen Deposition
SIMULTANEOUS
& Ion Implantation
Y
ACTIVITY HIGH RADIATION BACKGROUND
10
101 2
Φ = 109 s- 1
τ = 1000 s
101 1
NB
NA
101 0
· Pulsed Muon Beam
109 0
10
· Active BG suppression, Detector segmentation, ...
Slowpbar, RIKEN March 16, 2005 – P. Strasser
D2
A* → B
13
Population
ACCUMULATION of DAUGHTER NUCLEI
· LIMITATION (static target): T1/2 > 10 min.
H2 / D2
101 4
X RI beam COMPLETELY stopped in the target!
Y
A*
Beam Impurity
(1%)
101
102
103
Time [s]
104
105
Using Solid Hydrogen Films
X Advantages
· WINDOWLESS TARGET in vacuum
· WELL-DEFINED interaction region
· EASY TARGET EVAPORATION and REPLACEMENT
· RI BEAM: Impurities, Emittance, Energy spread, ...
NOT CRITICAL
No Cooling Needed!
Different µA* Formation Schemes
MUON BEAM ENERGY
· ACCUMULATION of DAUGHTER NUCLEI
X Other Considerations
· Magnetic confinement field
· Pulsed muon beam
RI BEAM ENERGY
NEW IDEAS ! e.g., using sputtering
vs. daughter nuclei accumulation
D2 Layer
H2/D2 Layer
µ¯
µ¯
D2 Layer
RI
RI
D2 Layer
D2 Layer
µ¯
µ¯
RI
RI
Degrader
Degrader
Slowpbar, RIKEN March 16, 2005 – P. Strasser
LOW (2–4 MeV)
ULTRA-LOW (~0.1 MeV)
LOW (10–100 keV/u)
· SPUTTERING
HIGH (~10 MeV/u)
X Disadvantages
?
Feasibility Study
X EXPERIMENTAL SETUP for X-ray spectroscopy of muonic atoms formed
from implanted ions in solid hydrogen
X TEST EXPERIMENT at RIKEN-RAL Muon facility.
X Establish the feasibility of this method by using STABLE IONS.
X µCF RELATED STUDY: Helium transfer in Solid Hydrogen Films
X In the near future, experiment using LONG-LIVED ISOTOPES.
Slowpbar, RIKEN March 16, 2005 – P. Strasser
ISIS Facility at RAL
KARMEN
MARI
HRPD
eVS
GEM
DEVA
MAPS
PEARL
EC MUON FACILITY
SXD
MuSR
EMU
SANDALS
PRISMA
HET
TOSCA
800 MeV
SYNCHROTRON
RIKEN FACILITY
POLARIS
ROTAX
LOQ
SURF
CRISP
VESTA
IRIS
HEP Test Beam
70 MeV H¯ Linac
Slowpbar, RIKEN March 16, 2005 – P. Strasser
OSIRIS
RIKEN-RAL Muon Facility at ISIS
Port 3
Port 4
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Port 2
µA* Setup at RIKEN-RAL Port 4
Test Experiment to Implant Stable Ions in Solid Hydrogen Films.
µA* Setup
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Muon Beam Profile (1)
X8
X4
X6
X2
Photomultiplier output signal of counter X5
27 MeV/c surface µ+
Y9
27 MeV/c decay µ¯
Y8
Y7
Y6
Y5
Y4
Y3
Y2
ADC output with 27 MeV/c decay µ¯
X9
X7
X5
X1
X3
Y1
3000
10 cm
Muon Beam Profile Monitor
COUNTS
0
2000
1000
0
0
200
ADC-Y5 CHANNEL
Slowpbar, RIKEN March 16, 2005 – P. Strasser
400
Muon Beam Profile (2)
Relative Yield_y
B4 Current
Relative Yield_x
Horizontal and vertical muon beam profiles as a function of B4 dipole
magnet measured with surface muons at Port 4.
B4 Current
Center_y
Center_x
B4 Current
B4 Current
Slowpbar, RIKEN March 16, 2005 – P. Strasser
B4 Current
Sigma_y
Sigma_x
B4 Current
B4 Current
Muon Beam Momentum Tuning
10
4
Target: 1-mm H2 Layer
10
10
20
Data multiplied by (27/p)3.5
to correct for the expected
momentum dependence of
the intensity
3
15
2
0
2000
4000
6000
Elec. Counter Time Coin(1-2)
10
4
10
3
10
2
27-MeV/c Decay µ¯
(Port 4, Dec. 2001)
10
27-MeV/c Cloud µ¯
(Port 4, Dec. 2001)
5
27 MeV/c cloud µ¯
0
No Separator
at Port 4 !
e¯
24
µ¯
10
1
0
Arbitrary units
Counts / 20 ns
27 MeV/c decay µ¯
2000
4000
6000
8000
Elec. Counter Time Coin(3-4)
Slowpbar, RIKEN March 16, 2005 – P. Strasser
25
26
27
28
29
30
Muon Momentum [MeV/c]
31
32
Muon Stopping Distribution
X Negative Muon Beam at RIKEN-RAL Port 4
· Muon Source:
Decay Muon
Cloud Muon
· Momentum:
27 MeV/c
27 MeV/c
· Width (∆p/p):
~ 10 %
~ 7%
-1
· Beam size:
~ Ø40 mm
XMuon Stopping in Solid D2
· 1-mm D2 :
~ 60%
(3000 s-1)
· Silver Foil:
· Ratio:
-1
~ 5000 s
~ 20%
3
~ 15000 s
10.00
8.00
Gaussian Stopping Distribution
(center = 0.5 mm, σ = 0.6 mm)
6.00
4.00
2.00
0.00
0.0
Slowpbar, RIKEN March 16, 2005 – P. Strasser
(~3x)
12.00
µD Kα X-rays/ 103 spills
· Intensity:
if separator
installed !
0.5
1.0
1.5
2.0
D2 Film Thickness [mm]
2.5
µA* Setup (2)
Cryostat
Ion Beam
Optics
µA* Target
System
Muon
Beam
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Cryostat
µA* Target
(1)
Target
Holder
Silver
Cold Foil
Diffuseur
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µA* Target (2)
Diffuseur
Hydrogen gas
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Gas Handling System
Diffuseur
Gas Handling
System
Turbo Molecular
Pump
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Hydrogen gas
Hydrogen Gas
Purifier
µA* Target (3)
Beam Profile
Monitor
Ion Beam
Muon Beam
Hydrogen
Film
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Setup
Ion (3)
Source
Ion
Beam
Slits
Slits
EQ-1
Magnetic
Bend
EQ-2
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Duoplasmatron Ion Source
Ion Source
(Duoplasmatron)
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Ion Beam Transport Line
Ion
Source
X-Y Steerer
Slits
Beam Profile
Monitor
Ion
Beam
Slowpbar, RIKEN March 16, 2005 – P. Strasser
0.5-mm H2/D2 Deposition
10- 6
Argon Implantation (x3)
6-µm D2 Deposition
Main Vacuum [mbar]
Target Temperature [K]
0.5-µm D2 Deposition
10- 7
10- 8
10- 9
5.0
4.0
3.0
15:00:00
16:00:00
Argon Ion Range in Solid D2
17:00:00
Time
18:00:00
19:00:00
Target Temperature [K]
Main Vacuum [mbar]
Target Preparation
2.0
Beam Profile on Target
500
Beam Profile [a.u.]
400
300
200
100
0
-100
X-Axis (start)
Y-Axis (start)
-200
-300
Slowpbar, RIKEN March 16, 2005 – P. Strasser
-20
-10
X-Axis (end)
Y-Axis (end)
0
Position [mm]
10
20
Vacumm Pressure [mbar]
Sputtering of Solid Deuterium Films
µm D2
1 -µ
2 10-7
2440 s
33-keV Argon Beam
µA/10cm2)
( ~ 4µ
1 0-7
9 10-8
8 10-8
7 10-8
6 10-8
5 10-8
B. Stenum et al.,
NIM. B 48 (1990) 530.
0
1000
2000
3000
Time [s]
· Sputtering Yield ≈ 350 D2/Ar Ions
2
(~40 nm/µA/cm )
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Argon Ion Range
in Solid D2
µA* Setup (4)
X-Ray
Detector
Gamma-Ray
Detectors
Slowpbar, RIKEN March 16, 2005 – P. Strasser
µA* Setup Detector-Target Layout
Ge PLANAR:
2 0 0 m m2 x 1 3 mm
Be window: 127 µm
[keV] C
Kα 75.3
Kβ
Lα
89.2
14.0
N
O
102.4 133.5
121.4 158.4
19.0
24.9
Ge COAXIAL: (2265 mm2)
Ø54.7 mm x 41.8 mm
Al window: ≤ 1 mm
µe-4
0
5
100-µm SUS
window
µe-3
µe-2
10-µm Ag
window
µe-1
1.0
Attenuation
0.8
0.6
100µm Fe
1mm Al
10um Ag
0.4
0.2
0.0
0
20
40
60
80
Photon Energy [keV]
Slowpbar, RIKEN March 16, 2005 – P. Strasser
100
Si(Li):
70 mm2 x 3.5 mm
Be window: 25.4 µm
50-µm SUS
window
10-µm Ag
window
10 cm
Muonic Siver X-Rays
µA* Target System
Muonic Silver X-rays
from the Cold Foil
µAg
600
Counts
500
Cold Foil
(100-µm Ag)
105Ag
2p1/2-1s1/2
400
107Ag
300
200
100
Germanium
γ-Ray Detector
Slowpbar, RIKEN March 16, 2005 – P. Strasser
2p3/2-1s1/2
0
3100
3150
3200
Energy [keV]
(1) 0.5-mm H2/D2 + 7-µm D2(Ar-multi)
Ge(coaxial) γ-Ray Energy Spectra
Si(Li) X-Ray Energy Spectrum
2600
Total
µAr (2p→1s)
644 keV
2400
2200
800
dµ
µ
−
pµ
µA*
2000
dµ
1800
H2 / D2
1600
1400
1200
D2
X-Rays
Two-Layer Arrangement
600
650
Counts / 0.89keV
800
800
700
Short Delayed
µAr (2p→1s)
Ag(e)
L-complex
400
µp Kβ
200
0
1.0
1.5
2.0
500
500
400
400
300
300
200
700
Energy [keV]
Slowpbar, RIKEN March 16, 2005 – P. Strasser
2.5
3.0
3.5
Energy [keV]
Implanted Ar Ions in 5 µm
16
2
~10 at/cm (500 ppm)
12'170 kspills
600
600
650
(µAr)(e) Kα
600
40
900
600
µp Kα
700
Energy [keV]
700
Counts / 20 eV
Counts / 0.89keV
2800
(67.6 hrs)
Long Delayed
µAr (2p→1s)
600
650
Energy [keV]
700
4.0
dµ Atom Scattering in Solid Deuterium
Deceleration of Muonic Hydrogen
Atoms in Solid Hydrogens
A. Adamczak, Hyperfine Interactions 119 (1999) 23.
dµ Mean-Free-Path in Solid D2
dµ speed (µm/µs)
103
104
2
10
102
mean-free-path (µm)
d µ (1/ 2 → 3/ 2) + D2
d µ (3/ 2 → 1/ 2) + D2
101
d µ (1/ 2) + D2
100
d µ (3/ 2) + D2
C(Ar)=0.1%
10- 1
C(Ar)=1%
m.f.p. (dµ+Ar → µAr+d)
10- 2
10- 5
Slowpbar, RIKEN March 16, 2005 – P. Strasser
10- 4 10- 3
10- 2 10- 1 100
dµ energy (eV)
φ = 1.4
101
102
(2) 0.5-mm D2(Ar-multi)
Ge(coaxial) γ-Ray Energy Spectra
Counts / 0.89keV
2600
2400
1500
µ−
dµ
2200
µA*
2000
1800
X-Rays
D2
µd Kα
(µAr)(e) Kα
1000
µd
Kβ
500
Ag(e)
L-complex
1600
0
1.0
Single D2 Layer
1400
600
650
Short Delayed
µAr (2p→1s)
500
400
400
300
300
200
600
650
700
Energy [keV]
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Long Delayed
µAr (2p→1s) 12’560
600
500
3.0
3.5
4.0
Implanted Ar Ions in 0.5 mm
16
2
~10 at/cm (~ 6 ppm)
700
600
2.5
Energy [keV]
800
700
2.0
40
900
800
1.5
700
Energy [keV]
Counts / 0.89keV
Counts / 20 eV
Total
µAr (2p→1s)
644 keV
2800
Si(Li) X-Ray Energy Spectrum
kspills
(69.8 hrs)
600
650
Energy [keV]
700
Counts / 0.89keV
Total Energy Spectra (1-mm D 2)
(a)
???
1500
No Argon
1000
500
600
650
700
750
800
Counts / 0.89keV
Energy [keV]
2500
µAr (2p→1s)
(b)
2000
µAr (3p→1s)
µAr (4p→1s)
1500
1000
600
650
700
Energy [keV]
Slowpbar, RIKEN March 16, 2005 – P. Strasser
750
800
Counts / 0.89keV
Delayed Energy Spectra (1-mm D 2)
600
No Argon
400
200
0
600
650
700
750
800
Counts / 0.89keV
Energy [keV]
800
µAr (2p→1s)
600
µAr (3p→1s)
µAr (4p→1s)
400
200
0
600
650
700
Energy [keV]
Slowpbar, RIKEN March 16, 2005 – P. Strasser
750
800
(3) 1.0-mm D2(Ar-multi)
Implantation:
Distance:
20x
50µm
10x
100 µm
5x
200 µm
250
Single D2 Layer
1400
µA(2p-1s)
800
225
µA(2p-1s)
1200
µ−
200
700
dµ
D2
175
1000
600
µA*
µA(2p-1s)
X-Rays
150
500
800
125
distance between
implantation
400
600
100
300
75
400
200
Total γ-Ray
Energy Spectra
100
0
1300
Slowpbar, RIKEN March 16, 2005 – P. Strasser
~2 ppm
200
50
~1 ppm
~0.5 ppm
25
1400
1500
Ge(Eur) E total(1ch)
1600
0
1300
1400
1500
Ge(Eur) E total(1ch)
1600
0
1300
1400
1500
Ge(Eur) E total(1ch)
Normalized Counts (a.u.)
Transfer Yield
0.70
0.60
0.50
0.40
0.30
µAr(2-1)
0.20
µ Ar(e) K
0.10
Total Transfer (w/o Z)
Transfer Yield (w/ Z)
α
Z = Air (N2, O2)
0.00
0
1
2
3
4
5
6
7
8
Ar Concentration (ppm)
For a uniform target
Normalized data only
No correction applied yet !
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Y dAr =
φ C Ar λ dAr
λ 0 + φ C Ar λ dAr + φ C Z λ dZ
0.010
µAr(2-1)
0.008
Limitation on
the minimum
film thickness!
µAr(e) Kα
0.006
0.004
f(x) = 1 - exp(-x/a)
dµ Mean-Free-Path in Solid D2
a ≈ 20 µm
0.002
0
50
100
150
200
Distance between Implantation [µm]
d
D2
dµ
dµ
dµ
Implantation
µA*
µA*
Ar
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Ar
dµ speed (µm/µs)
103
104
2
10
102
0.000
d µ (1/ 2 → 3/ 2) + D2
250
mean-free-path (µm)
Norm. Counts / Implantation (a.u.)
dµ Atom Diffusion in Solid D 2
d µ (3/ 2 → 1/ 2) + D2
101
d µ (1/ 2) + D2
100
d µ (3/ 2) + D2
C(Ar)=0.1%
10- 1
C(Ar)=1%
m.f.p. (dµ+Ar → µAr+d)
10- 2
10- 5
10- 4 10- 3
10- 2 10- 1 100
dµ energy (eV)
φ = 1.4
101
102
Towards Radioactive Muonic Atoms
X Experiment using LONG-LIVED ISOTOPES under consideration, e.g., radium
isotopes of special interest for P&T violation in atoms (K. Jungmann, KVI).
X Need a NEW ION SOURCE to produce LONG-LIVED RI BEAMS.
X NOW at RIKEN-RAL: 1016 atoms needed in Ø5cm x 1mm D2 target (3000 µ¯/s).
Possible Improvements: 60 times!
X Need ~100x more in the ION SOURCE.
N = 10
1 day
Activity (Bq)
· 3 times (cloud µ¯)
10
10
16
101
atoms
100
1 week
1 month
10
10-1
10-2
1 year
108
10-3
10 years
10
10-4
100 years
6
10-5
3
X ACTIVITY versus HALF-LIFE.
10 years
4
10
10 y
4
103
Slowpbar, RIKEN March 16, 2005 – P. Strasser
105
107
109
Half-Life (sec)
1011
10-6
1013
Activity (Ci)
· 20 times (1 cm2 target)
102
1 hour
12
Periodic Table of Elements
Slowpbar, RIKEN March 16, 2005 – P. Strasser
New Surface Ionization Ion Source
New Collaborators: A. Taniguchi (Kyoto), S. Ichikawa (JAERI), H. Miyatake (KEK)
Seeds
First stable: Ba, …
then RI
Good for alkali metals & alkaline-earth metals!
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Future Prospects
Muon Beam Requirement for µA* Experiment:
X Muon Stopping in Solid Deuterium
· Momentum:
~ 27 MeV/c
· Width (∆p/p):
≤5%
· Beam intensity:
> 1 x 10
· Beam size:
≤ 1cm
7–8
s
2
X X-Ray and γ-Ray Detection System
· Muon beam:
XMuonic Atoms (in brief)
Transfer Rate: YX =
single
· Pulse width:
≤ 20–50 ns
· Repetition rate:
1–10 kHz
φλ Z
λ 0 + φλ Z
λ Z ≈ C Z Z × 1010 s −1
We need
pulsed
· Pulse structure:
Slowpbar, RIKEN March 16, 2005 – P. Strasser
-1
(approximation)
1017
NZ Nµ ≈
Z
(λZ<< λ0)
to produce 1 µA* per cm2.
NZ, Nµ: Z and µ¯ in 0.5-mm D2
SUPER OMEGA Project
(K. Shimomura et al., KEK)
X Injection
at J-PARC Muon Facility
· 2 normal solenoids ~ 400mSr
· Residual magnetic field on the proton beam
line ~10 Gauss
X Transport
· Curved superconducting solenoid
· Reduction of neutral background
· Selection of charged particle
X Extraction
· Dai Omega type axial focusing channel
· Strong focusing at the experimental position
· Selection of muon and positron by electric
separator
Not funded yet !
Slowpbar, RIKEN March 16, 2005 – P. Strasser
SUPER OMEGA Project
(K. Shimomura et al., KEK)
Beam Optics Calculation
X Yield Estimation
· Solid angle: ~ 400mSr
· Momentum: 27 MeV/c
· Momentum width: 4–10%
+
8
· Surface Muons (µ ): 2–5 x 10 s
-
· Cloud Muons (µ ):
-1
6
4–10 x 10 s
-1
+
X Science (µ )
4
· Ultra-Slow Positive Muon 2–5 x 10 s
-1
· Muon micro-beam, ...
–
XScience (µ )
· µA* Formation
· Element Analysis by Muon Spectroscopy
· ...
Slowpbar, RIKEN March 16, 2005 – P. Strasser
by K. Ishida (RIKEN)
My Dream at J-PARC Muon Facility
3GeV Proton
~1x107 µ~5x108 µ+
29MeV/c µ+/µ-
Muon Target
Slowpbar, RIKEN March 16, 2005 – P. Strasser
Summary
X In the near future, investigations of unstable nuclei
using muonic atom spectroscopy will become
possible at facilities with intense µ¯ and RI beams.
X Meanwhile, using dedicated long-lived RI ion source,
radioactive muonic atom study will soon be a reality
at new intense muon facility.
There will be a unique opportunity
at the new J-PARC MUON FACILITY.
and maybe in the near future at a NEUTRINO FACTORY !
Slowpbar, RIKEN March 16, 2005 – P. Strasser