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Spectroscopy and lifetime measurements at ReA12
Hiro IWASAKI(NSCL/MSU)
7/12/2014Recoil Separator for ReA12
workshop1
Example : neutron-rich Ni isotopes
7/12/2014Recoil Separator for ReA12
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spectroscopy of band structure built upon the 02,3
+ states Y.Tsunoda et al., Phys. Rev.C 89 (2014) 031301(R)
S.Suchyta et al.,PRC89(14) 021301(R)
68Ni
Low-energy reactionsStudies beyond the 2+ states
Example2 : 3NF effects in n-rich O and Ca
7/12/2014Recoil Separator for ReA12
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transition rates and comparison to theory
G.Hagen et al., PRL109(12)032502
high-energy gamma-ray detectionmeasurements of short lifetime (t≤1ps)
A.Gade, R.V.F.Janssens et al.,PRC74(06)021302(R)
Recoil Distance Method
7/12/2014Recoil Separator for ReA12
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model-independent determination of transition rates
Advantages Disadvantages∙ use of various reactions∙ access to higher-lying states∙ access to shorter (<1ps) lifetimes
∙ needs to measure at several distances∙ broad charge-state distributions∙ feeding effects (need g-g coincidence)
Lifetimea sensitive probe for nuclear structure… B(E2), B(M1)
Recoil Separator for ReA12 workshop
57/12/2014
Example : 128Xe + Fe at 525MeVDetailed 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.
W.Rother et al.,NIMA654(11)1962mg/cm2 Fe target4mg/cm2 Nb degrader
Inverse-kinematics Coulomb excitation + RDDS lifetime measurements
qgr=10o
With measured lifetime,GOSIA calculations are possibleto determine Q(2+)
Energy dependence of Coulex
7/12/2014Recoil Separator for ReA12
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HIE-ISOLDEthe scientific opportunitiesCERN-2007-008 (2007)
Multiple (safe and unsafe) Coulex : best at ReA12
CC (ECIS97) calculations for Sn+Pb
10
ReA12 FRIB
Excitation beyond the first 2+ state
7/12/2014Recoil Separator for ReA12
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Examples : 76Kr + Pb at 4.4AMeV 132Sn + Pb at 50AMeV
(Ec=10AMeV) (Qgr=6.5deg)
E.Cle’ment et al.,PRC56(2007)054313
Need to cover large scattering angles
Grazing angles at 12AMeV
7/12/2014Recoil Separator for ReA12
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Examples : Ein = 12AMeV
32Mg + Pb 23 20
66Fe + Pb 26 20
132Sn + Pb 30 18
32Mg + Fe 11 6
66Fe + Fe 15 7
132Sn + Fe 21 6
Qgr(CM) [degrees] Qgr(Lab) [degrees]
Ec=10AMeV
Ec= 5AMeV
Charge States …
7/12/2014Recoil Separator for ReA12
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Example : 48Ca (5AMeV) + Au/C
N.K.Skobelev, ISSN0020-4412IET2008, 51, p351
Beam
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Lifetime setup at ReA12
ReA12
38cm
45-50 cm
Primary Secondary b(g) Magic angle Angle for lifetime DZ150AMeV 90AMeV 0.41(1.10) 67 deg < 40 deg (Db=10%) 13cm ReA12 12AMeV 0.16(1.01) 80 deg < 50 deg 6cm (can use both rings)
Requirements …
7/12/2014Recoil Separator for ReA12
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Angle Energy PID others
∙ (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 *)
Rotatableor ~8 degrees acc.
A and Z (and Q)A >= 100
dE>=10%
*) tracking information for recoils (x,y,x’y’,d) is required with 1mm,1mrad,1% precisions for Doppler-shift corrections and possible alignment measurements
Summary
7/12/2014Recoil Separator for ReA12
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∙ 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.
Thank you
7/12/2014Recoil Separator for ReA12
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Backup
7/12/2014Recoil Separator for ReA12
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Spectroscopy and lifetime measurements at ReA12
7/12/2014Recoil Separator for ReA12
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New (old) reactions can be used with RIB
- Deep inelastic- Multi Coulex
to accessmedium-spin states of n-rich nuclei
GRETINA at NSCL
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