Spectroscopy and
lifetime measurements at ReA12
Hiro IWASAKI
(NSCL/MSU)
7/12/2014
Recoil Separator for ReA12 workshop
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Example : neutron-rich Ni isotopes
spectroscopy of band structure built upon the 02,3+ states
Y.Tsunoda et al., Phys. Rev.C 89 (2014) 031301(R)
68Ni
S.Suchyta et al.,
PRC89(14) 021301(R)
7/12/2014
Low-energy reactions
Studies beyond the 2+ states
Recoil Separator for ReA12 workshop
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Example2 : 3NF effects in n-rich O and Ca
transition rates and comparison to theory
G.Hagen et al.,
PRL109(12)032502
A.Gade, R.V.F.Janssens et al.,
PRC74(06)021302(R)
high-energy gamma-ray detection
measurements of short lifetime (t≤1ps)
7/12/2014
Recoil Separator for ReA12 workshop
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Recoil Distance Method
model-independent determination of transition rates
Lifetime
a sensitive probe
for nuclear structure
… B(E2), B(M1)
Disadvantages
Advantages
∙ use of various reactions
∙ access to higher-lying states
∙ access to shorter (<1ps)
lifetimes
7/12/2014
∙ needs to measure at several distances
∙ broad charge-state distributions
∙ feeding effects (need g-g coincidence)
Recoil Separator for ReA12 workshop
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Example : 128Xe + Fe at 525MeV
Detailed structure information is to be studied by
(multiple) Coulomb excitation and lifetime measurements.
Higher beam energies (>5AMeV) increase cross sections
(particularly for higher-lying states) and allow use of thick targets.
Inverse-kinematics Coulomb excitation
+ RDDS lifetime measurements
qgr=10o
7/12/2014
With measured lifetime,
GOSIA calculations are possible
to determine Q(2+)
W.Rother et al.,
NIMA654(11)196
2mg/cm2 Fe target
4mg/cm2 Nb degrader
Recoil Separator for ReA12 workshop
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Energy dependence of Coulex
HIE-ISOLDE
the scientific opportunities
CERN-2007-008 (2007)
CC (ECIS97) calculations for Sn+Pb
10
ReA12
FRIB
Multiple (safe and unsafe) Coulex : best at ReA12
7/12/2014
Recoil Separator for ReA12 workshop
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Excitation beyond the first 2+ state
Examples :
76Kr + Pb at 4.4AMeV
(Ec=10AMeV)
132Sn
+ Pb at 50AMeV
(Qgr=6.5deg)
E.Cle’ment et al.,
PRC56(2007)054313
Need to cover large scattering angles
7/12/2014
Recoil Separator for ReA12 workshop
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Grazing angles at 12AMeV
Examples : Ein = 12AMeV
Qgr(CM) [degrees]
32Mg + Pb
23
Qgr(Lab) [degrees]
20
66Fe
+ Pb
26
20
132Sn
+ Pb
30
18
32Mg
+ Fe
11
6
66Fe
+ Fe
15
7
+ Fe
21
6
132Sn
7/12/2014
Recoil Separator for ReA12 workshop
Ec
=10AMeV
Ec
= 5AMeV
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Charge States …
Example : 48Ca (5AMeV)
+ Au/C
N.K.Skobelev, ISSN0020-4412
IET2008, 51, p351
7/12/2014
Recoil Separator for ReA12 workshop
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Lifetime setup at ReA12
38cm
ReA12
Beam
45-50 cm
Primary
Secondary
150AMeV 90AMeV
ReA12
12AMeV
7/12/2014
b(g)
Magic angle Angle for lifetime
DZ
0.41(1.10)
67 deg
< 40 deg (Db=10%) 13cm
0.16(1.01)
80 deg
< 50 deg
6cm
(can use both rings)
Recoil Separator for ReA12 workshop
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Requirements …
Angle
Energy
dE>=10%
Rotatable
or ~8 degrees acc.
PID
others
A and Z (and Q)
A >= 100
∙ (Multi) Coulex
0-20 degrees 5-10AMeV
A and Z (and Q) 104-5 rates at FP
(0-10 degrees for inv. with medium mass target)
∙ Lifetime
larger acceptance for different Q
*)
*) tracking information for recoils (x,y,x’y’,d) is
required with 1mm,1mrad,1% precisions
for Doppler-shift corrections and possible alignment measurements
7/12/2014
Recoil Separator for ReA12 workshop
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Summary
∙ Spectroscopy and lifetime measurements at ReA12
are discussed.
∙ Deep inelastic scattering and multiple Coulomb
excitation are useful reactions at ReA12 to access
medium/high-spin states of neutron-rich nuclei and
should be used in detailed spectroscopy.
∙ Requirements for experiment setup, particularly for
spectrometer to be prepared at ReA12, are discussed.
7/12/2014
Recoil Separator for ReA12 workshop
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Thank you
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Recoil Separator for ReA12 workshop
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Backup
7/12/2014
Recoil Separator for ReA12 workshop
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Spectroscopy and lifetime measurements
at ReA12
New (old)
reactions
can be used
with RIB
- Deep inelastic
- Multi Coulex
to access
medium-spin
states of
n-rich nuclei
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Recoil Separator for ReA12 workshop
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GRETINA at NSCL
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Recoil Separator for ReA12 workshop
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