Spectroscopy and lifetime measurements at ReA12

Hiro IWASAKI(NSCL/MSU)

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Example : neutron-rich Ni isotopes

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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

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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

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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

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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

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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

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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 …

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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 …

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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

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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

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Backup

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Spectroscopy and lifetime measurements at 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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