Mass Measurements at CSRe and Related Physics Yuhu Zhang (Y. H. Zhang) Institute of Modern Physics, Chinese Academy of Sciences Lanzhou , China （ ）

● Brief introduction to the collaboration ● Principle & method of measurements in CSRe ● Results and discussions ● Summary and perspectives Outline

H. S. Xu Y. H. Zhang, X. L.Tu, X. L. Yan, M. Wang. X. H. Zhou,Y. J. Yuan, J. W. Xia, J. C. Yang, X. C.Chen, G. B. Jia, Z. G. Hu, X. W. Ma, R. S. Mao, B. Mei, P. Shuai, Z. Y. Sun, S. T. Wang, G. Q. Xiao, X. Xu, Y. D. Zang, H. W. Zhao, T. C. Zhao, W. Zhang, W. L. Zhan (IMP-CAS, Lanzhou, China) Yu.A. Litvinov, S.Typel (GSI, Darmstadt, Germany) K. Blaum (MPIK, Heidelberg, Germany) Y. Sun (Shanghai Jiao Tong University, Shanghai, China) Baohua SUN (Beihang University) H. Schatz, B. A. Brown (MSU, USA) G. Audi (CSNSM-IN2P3-CNRS, Orsay, France) T. Yamaguchi (Saitama University, Saitama, Japan} T. Uesaka, Y. Yamaguchi (RIKEN, Saitama, Japan) CSRe mass measurement collaboration More than 30 researchers are involved in this collaboration

GSIMSURIKENDomesticMPIKOrsay Yu. A. Litvinov G. Audi K.Blaum T. Uesaka H. Schatz B. A. Brown CSR mass measurement collaboration B. H. Sun F. R. XuY. Sun

Storage rings CSR at IMP CSRe SFC (K=69) SSC(K=450) CSRm RIBLL1 RIBLL2 IMP

Storage rings CSR at IMP IMP

Our Research Aims  Improving the IMS technique in CSR  Measuring the masses of A < 100 short-lived neutron-deficient & neutron-rich isotopes  Studying the associated physics in Nuclear structure Nuclear astrophysics  Studying the in-ring decay

Injection ToF e-Cooler Principle & method of Measurements H. Wollnik, Y. Fujita, H. Geissel, G. Münzenberg, et al.

Injection ToF Principle & method of Measurements Isochronous Mass Spectrometry

Detector Timing Detector 10 mm 9 BeTarget  t  CSR

Some technique developments for IMS mass measurement in CSRe-Lanzhou (2008 → present)

ToF Detectors used for IMS at ESR & CSR Injection ToF Thin C foil 19  m

ToF Detectors used for IMS at CSR B. Mei et al., NIM A 624, 109 (2010) X. L. Tu et al., NIM A 654, 213 (2011) W. Zhang et al., NIM A 756, 1 (2014) Continuous effort to improve the time resolution of ToF Efficiency 20%-70 % Time resolution Sigma = 37 ps

IMS at CSR: high resolving power IMS: Isochronous Mass Spectrometry

34 Ar & 51 Co close m/q Phys. Lett. B 735,327 (2014) Another development … 58 Ni beam: Charge & Frenquency Resolved IMS

Time vs Amplitude Analysis for: 51 Co & 34 Ar

This work ME( 34 Ar)= (15) keV AME03: ME( 34 Ar)= (4) keV This work: ME( 51 Co)= (48) keV P. Shuai et al., Phys. Lett. B 735,327 (2014) Time difference 1.63 (35) ps

T 1/2 = 71  s Ex=2645 keV Obtained from 30 turns Both the mass and partial half- life are measured simultaneously for T 1/2 = 71  s isomer in 94 Ru. It shows the capability of IMS Period In-ring decay In-ring decay of T 1/2 = 71  s Isomer in 94 Ru isomer Counts Number of isomer Time (  s)

Isochronous Mass Spectrometry Double ToF Nuclides used for M/Q calibration are within a time window which is not far from the isochronous condition.

Injection Double ToF Detectors 18 m ( 85 ns ) Collaborated with GSI Double ToF  t = 1.3~1.4

Two ToFs: Simulations Without correction With Without With correction Double ToF

Results and Discussions (2008 → present)

Mass measurement results at CSRe-Lanzhou 1.B. Mei et al., NIM A 624, 109 (2010) 2.X. L. Tu et al., PRL 106, (2011) 3.X. L. Tu et al., NIM A 654, 213 (2011) 4.Y. H. Zhang et al., PRL 109, (2012) 5.X. L. Yan et al. Astrophys. J. Lett. 766, L8 (2013) 6.H. S. Xu et al., IJMS 349, 162 (2013) 7.X. L. Tu et al., J. Phys. G41, (2014) 8.W. Zhang et al., NIM A 756, 1 (2014) 9.B. Mei et al., Phys. Rev. C 89, (2014) 10.P. Shuai et al., Phys. Lett. B 735,327 (2014) Beams: 56 Ni, 78 Kr, 86 Kr, 112 Sn, 36 Ar Precision ~10 -7 ( keV) Remeasured 27 Newly measured 26 Double ToF

Nuclides at the rp- & vp-process paths p – process C. Weber et al., Phys. Rev. C 78, (2008) V.-V. Elomaa et al., Phys. Rev. Lett. 102, (2011) E. Haettner et al., Phys. Rev. Lett. 106, (2011) F. Herfurth et al., Eur. Phys. J. A, 47,75 (2011) CSRe (IMP, Lanzhou) X. Tu et al., Phys. Rev. Lett. 106, (2011) Slide from Klaus Blaum

Nuclear Astrophysics:  65 As: on the waiting point nuclide 64 Ge, PRL 106, (2011)  45 Cr: on the Ca-Sc cycle in the rp-process Astrophys. J. Lett. 766, L8 (2013)  82 Zr: on the reaction path of p-process at A=80-86 in progress Nuclear Structure:  53 Ni: on the isospin multiplet mass equation PRL 109, (2012)  51 Co: on isospin non-conserving forces Phys. Lett. B 735,327 (2014)  52 Co, 56 Cu: np interaction at N=Z=28 closed shell  53 Sc: on the new N=32 magic number in progress Mass measurement results at CSRe-Lanzhou

Impact of CSRe Mass Measurement Mass Measurement of Tz=-1/2 Nuclei ( 65 As)  Waiting Point in the rp-process of X-ray burst

Reaction path Light curve Element abundance 65 As S p ( 65 As) >-250 keV (AME2003) Waiting point at 64 Ge in the Type I X-ray burst ? Results from CSRe: (1) waiting point 64 Ge

S p ( 65 As) =  keV  Light curve of Type I x-ray burst 89%–90% of the reaction flow passes through 64 Ge via proton capture indicating that: 64 Ge is not a significant rp-process waiting point. 11 Abundance of burst ashes X.L. Tu et al., PRL 106, (2011) Results from CSRe: (1) waiting point 64 Ge

Impact of CSRe Mass Measurement Mass Measurement of Tz=-3/2 Nuclei ( 45 Cr)  Test of Ca-Sc Cycle in rp Process

T=1.5 GK  =10 4 g/cm 3 T=10 3 sec. van Wormer et al., Astrophys. J. 432, (1994) 326 Results from CSRe: (2) Ca-Sc cycle

Precision mass of 45 Cr  Net work calculations  The predicted Ca-Sc cycle in x-ray burst may not exist Results from CSRe: (2) Ca-Sc cycle

Impact of CSRe Mass Measurement Mass Measurement of A=80 Nuclei ( 82 Zr)  path way of vp-process at A=80-86

2.0GK, AME2003 In progress Results from CSRe: (3) pathway of p-process at A=80-86 The reaction path of vp-process is uncertain due to unknown masses

2.0GK, AME2012+CSR In progress Results from CSRe: (3) pathway of p-process at A=80-86 The reaction path of vp-process at A=80-86 is determined

Impact of CSRe Mass Measurements Mass measurement of Tz=-3/2 nuclei ( 53 Ni)  test of Isospin multiplet mass equation

N = Z - 3/2 g.s - 1/2 IAS + 1/2 IAS + 3/2 g.s Neutron Proton (A,T,J  ) Degenerate if no charge-dependent Interaction, and  nH corrected for. - 3/2 - 1/2 + 1/2 + 3/2 Charge-dependent effects M(A,T,T z )=a(A,T)+b(A,T)T z +c(A,T)T z 2 Any charge-dependent effects are two body interactions and be regarded as a perturbation. Results from CSRe: (4) test IMME equation in pf shell

Test the IMME: the case of A=33,T=3/2 Breakdown of the Isobaric Multiplet Mass Equation at A= 33, T=3/2 F. Herfurth, PhysRevLett (2001)

d coeficients increase gradually up to A=53 for which d is 3.5  deviated from zero. Test the IMME in fp shell nuclei Y.H. Zhang et al., PRL 109, (2012)

Shell model calculations

C. Dossat et al., Nucl. Phys. A792 (2007) Beta-delayed proton 63%5.4% Mass Excesses uncertainty: 0.6 keV 25 keV 3. 4 keV 19 keV 53 Mn gs 53 Ni gs 53 Fe IAS 53 Co IAS

Results from CSRe: (5) INC-forces Isospin non-conserving force plays an important role in pf-shell

Impact of CSRe Mass Measurements Mass Measurement of Tz=-1 Nuclei ( 52 Co and 56 Cu)  ehaviour of np interaction at 28 closed shell

Behaviour of np interaction around 208 Pb L. Chen et al., Phys Rev Lett, 102, (2009) ProtonNeutron np interaction strength depends on the overlap of their wave functions

Proton and neutron shell closure 208 Pb 56 Ni

56 Cu (29,27) 52 Co (27,25) Behaviour of np interaction around 56 Ni np interaction strength depends on the overlap of their wave functions 28

Impact of CSRe Mass Measurements Mass Measurement of neutron-rich Nuclei ( 53 Sc … )  On the new magic number at N=32

Results in Ti isotopes: N=32: shell gap, N=34: not shell gap Ti 50 Ti 52 Ti 54 Ti 56 Ti N B(E2,  ) (100e 2 fm 4 ) D.-C. Dinca et al., PRC (R) (2005) R.V.F. Janssens et al., PLB 546, 22 (2002) B. Fornal et al., PRC 70, (2004) Results from CSRe: (7) N=32 magic number

D. Steppenbeck et al., Nature 502, 207 (2013) In progress New shell closure or magic number was predicted in N=32 & 34 Ca isotopes based on the theory including tensor force or microscopically the 3N force. It was confirmed via mass measurements & in-beam  spectroscopy in Ca isotopes. Our mass measurements show that N=32 magic number still persist in Sc Comparison with theory

1)IMS becomes available in CSRe-Lanzhou and some results have been obtained in the very neutron-deficient region below A=100 2) In-ring decay is observed and partial half-life measured which shows the capability of IMS at CSRe 3) Mass measurement for the shortest state of 70  s is achieved which may be a “record ” in IMS 4) Double ToF system has been developed which may improve the precision of IMS in CSRe and broaden the region of mass measurement 5) Some issues in nuclear astrophysics and nuclear structure have been touched on the basis of mass measurements in CSRe. Summary and perspectives

Injection Schottky mass spectrometry collaborated with GSI + Stochastic cooling Schottky Pick-up Summary and perspectives

136 Xe 124 Sn 100 Mo 86 Kr 64 Ni 48 Ca 92 Mo 58 Ni 78 Kr 112 Sn Continuing the mass measurements at both proton and neutron rich sides using IMS

CRYRING FAIR HESR HIAF CR Summary and perspectives

HIAF ① Nucl. Structure ② Irridiation ③ Ribll ④ Exp. Storage Ring ⑤ External target terminal ⑥ e – Ion resonance spectrometer ⑦ e- nucleus colider ⑧ H.E irradiation ⑨ High energy density

Institute of Modern Physics, CAS, Lanzhou Thank you for your attention !

Time vs Amplitude Analysis for: 51 Co & 34 Ar This work ME( 34 Ar)= (15) keV AME03: ME( 34 Ar)= (4) keV This work: ME( 51 Co)= (48) keV Tz=-3/2 Tz=-1 Tz =  1/2