26th Jan. 2010 Physics of Nuclei at Extremes, TokyoTech 1
Recent activities with slow andRecent activities with slow andstopped RI at Tohoku-Cyclotronstopped RI at Tohoku-Cyclotron
Cyclotron and Radioisotope Center (CYRIC), Tohoku Univ.:K. Shimada, S. Hoshino, S. Izumi,H. Ouchi, A. Sasaki, T. Wakui, T. Shinozuka,
RIKEN: Y. Miyashita
KUR: M. Tanigaki
JAEA: M. Asai, N. Sato
TOHOKUUNIVERSITY
International Workshop on Physics of Nuclei at Extremes, Jan. 2010, TokyoTech
1.Introduction of CYRIC2.Production of medium- heavy
neutron-rich nuclei1. RF Ion-guide ISOL
3.Recent results1. half life of 103mTc and
105mRu2. g-factor of 109mRh and 132mI
26th Jan. 2010 Physics of Nuclei at Extremes, TokyoTech 2
A
B
2
110
9
8
7
6
4
53
A AVF Cyclotron (K=110 MeV)B HM12 Cyclotron (production of positron emitters for PET)1 RI production3 High-intensity fast neutron
(Ep = 20-80 MeV 、 E = 1 MeV 、 106 n/cm2sA)
4 Large acceptance -ray detector array (Hyperball2) (6 Clover type + 14 Single type)
5 Heavy-ion irradiation (in air)7 Material irradiation8 High-resolution beam line and large scattering chamber9 Charged particle radiation therapy10 Beam swinger and Large solid angle neutron detection system
Slow RIB facility
2 RF ion-guide isotope separator on-line (RFIGISOL)
6 Surface ionization ion source for electron EDM measurement
Cyclotron and Radioisotope Center (CYRIC), Tohoku University
Cyclotron facility
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Purpose and backgroundNuclear structure of the medium-heavy neutron-rich nuclei
Life times and B(E2) of isomers Nuclear moments
Independent of nuclear structure model Single-particle energies and configurations of wave function
Known magnetic moments
N=50 N=82
Z=50
Z=28
Stable
(Sn)
(Ni)
High-melting point↓
hardly produced byISOLDE type ISOL
↓Development of
RFIGISOL(BigRIPS, FRS)
100Zn
132Sn
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Comparison of RI Production methods
Projectile-fragment separators In-flight A primary beam > A 2ndary beam
ISOL (⊃ RFIGISOL) A primary beam<<A 2ndary beam<A target
Target fragmentation Fission of 238U etc.
⇒ Middle-heavy neutron-rich nuclei
RFIGISOL High-melting-point and short-life RI⇒
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Correction of fission products with gas
Stop, thermalization and ionization ISOL: Thermal diffusion and surface ionization RFIGISOL: Large He gas volume and avoidance of
neutralization Independent of chemical properties Highest ionization energy of He
How are the fission products collected to the nozzle?
300 mm
20
0 m
m
Exit hole1 mm
U target
Fission products
3-kPa He
Gasstream DC field
RF field
RFIGISOLISOL
~3000K
U target
Proton
Proton
Recoil with several MeV
Recoil, ~MeV
=Ion+
+Ionizer
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Φ220 mmΦ220 mm
exit hole1.2 mm
Base film: 50-μm-thick kaptonElectrodes: 360 rings at 0.6-mm intervals
EDC
ERF
Track of ions
RF electrodes (RF carpet)
y
x
Trapping potential(for ion in resonance)
x
y RF phase
originally developed by M. Wada, RIKEN
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Typical parameters of RFIGISOL
Target: natural Uranium(Effective thickness:
190 mg/cm2)
Stop and thermalization: He gas (3 kPa), ~104 cm3
Guide: DC field(~5 V/cm)
Giude: RF field(~3 MHz, ~50 Vpp)
Extraction: Gas jet +DC field (~1 kV)
Mass spectrometer
Proton beam(50 MeV, 1 A)
Acceleration: DC 30 kV
CYRIC2nd target room
m
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Photo ~ RFIGISOL chamber
proton
Acceleration: DC 30 kV
U target
He gas: 3 kPaDC field: 5 V/cmRF field: 3 MHz,50 Vpp
Massspectrometer
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112Rh ~4000112Ru ~400
100Nb ~1300100Zr ~1300100Y ~400
91Rb ~400
80As ~20080Ge ~200
119Cd ~800119Ag ~400
78Ni
Fission production
cross section
Yields with RFIGISOLPrimary beam: Proton, 50 MeV, 1 μAYield at beam-line end, after passing mass spectrometer Stable line
107Tc ~2400 107Ru ~4600
[particles/sec]
109Tc ~1300 109Ru ~1300
111Tc ~1100 111Ru ~7100?
114Pd ~9000
Bold: 2009Normal: 2007
105Tc ~2400
100Zr
132Sn
10 mb
1 mb
0.1
125Pd (BigRIPS)
ObtainedYields
∝Expected Yields
132Te ~1000
Recent experimentsT1/2: 103mTc, 105mRu
g-factor: 109mRh, 132mI
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Recent experiments (1)Life-time measurement
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Setup of life-time measurement
Beam monitor (co-axial Ge)1. Implantation: ~1τ
2. Transfer : ~5 s
3. Measurement: ~1τ
Detectors for life-time measurement
good time resolutionPlanar Ge: ~1 nsBaF2: ~0.01 nsSystem: 5 ns
good energy resolution
10-ns isomers→Measurable
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Preliminary results– 163.74 keV : 55 ns → ~18 ns– 246.26 keV : ~15 ns
1ch = 0.25 nsec
105Ru103Tc
[Y. Miyashita, Tohoku Univ. / RIKEN][K. Shimada, H. Ouchi, Tohoku Univ.]
Preliminary result– 83.38 keV : ~40 ns
Recent experiments (1) Life of Isomer
(5/2-,3/2-)
3/2+,5/2+
(5/2)+
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Recent experiments (2)g-factor measurement
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Time differential Perturbed Angular Correlation methods (TDPAC)
...)(cos1)( 222 PAW
)()exp(),( 0 tWT
tNtN L
)2cos(4
3
),90(),180(
),90(),180()(
L22 tA
tNtN
tNtNtR
det. 10°
det. 290°
det. 3180°
° intensity distribution
extBg N
L
Bext
tL
T1
2
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Ge detectors
Magnet(0.34 T)
[Y. Miyashita, Tohoku univ. / RIKEN]On-line TDPAC method(Time differential perturbed angular correlation)
Tape transport system Detection system
g = 0.78 + 0.17 - 0.03 [N]
BaF2 detectors
Tape
TDPAC spectrum
B = 0.34 T
(2) g-factor in 109mRh (Ex=225.98 keV, T1/2=1.66 ms)
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I=3/2+ I=5/2+ I=3/2+ I=5/2+
(2+) ⊗(g9/2)93Nb 4.9483(3) 4.8049(2) (4+) ⊗(g9/2)93Nb 2.2496(1) 2.8773(1)
(2+) ⊗(g7/2)123Sb 1.4781(2) 1.8672(2) (4+) ⊗(g7/2)123Sb 0.57899(1) 1.22493(2)
(2+) ⊗(d5/2)141Pr 2.3047(3) 3.1587(2) (4+) ⊗(d5/2)141Pr -1.3430(3) 0.55323(4)
(2+) ⊗(d3/2)169Tm 0.871(2) 0.586(2) (4+) ⊗(d3/2)169Tm 3.294(19) 2.317(5)
(2+) ⊗(s1/2)193Ir 0.4561(1) 0.5389(2) (4+) ⊗(s1/2)193Ir 1.9024(10) 1.5719(3)
I=3/2+ I=5/2+
1.17 +0.23+0.03. 1.95 +0.38+0.05 - 0.02 - 0.03 - 0.03 - 0.05
or
1
111
21
111
2gI II
IIjjg
II
IIjjgCCcCCj
magnetic moment
109Rh 225 keV statesimple single-particle + excited-core coupling a proton core: excited 2+ or 4+ in 108Ru
1g9/2, 1g7/2, 2d5/2, 2d3/2, 3s1/2
of single-particle ground state
Magnetic moments
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( Bhf = +26.5 ±0.5 T )PAC spectrum in the Ni foil
Magnetic moment in 132mI
= +(2.06 ± 0.18)NBaF2 detectors×3
Tanigaki, PRC80(2009)034304
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Comparison of a simple jj-coupling model of odd-odd nucleus
(N) Ref.Experiment +2.06 ± 0.18 This work +2.22 ± 0.30 Singh et al. by TIPACCalculation (g7/2)(d3/2)−1 +2.40 (d5/2)(d3/2)−1 +2.83
Values for empirical g factors (g7/2) +2.80 Av. 131,133I (d5/2) +2.81 Av. 129,131I (d3/2)−1 +0.75 Av. 131Te, 133Xe
←proton-odd
←neutron-odd
odd-odd nucleus is described based on a jj-coupling model
)1(2
)1()1()(
)(2
1),(
I
jjjjgg
IggNZ
nnppnp
np
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SummaryCYRIC facility
2 cyclotrons and 10 beam lines Production of RI beam using RFIGISOL
RFIGISOL ISOL specified for high-melting-point and short-
life nuclei Large He gas buffer and RF carpet
Recent results life-time : 105mRu , 103mTc
Planar Ge-BaF2 system g-factor and μ : 109mRh , 132mI
TDPACNext plan: g-factor of 105mRu
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Thank you for your attention
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