Mass Measurements at CSRe and Related Physics

Yuhu Zhang (Y. H. Zhang)Institute of Modern Physics, Chinese Academy of Sciences

Lanzhou 730000, China （ yhzhang@impcas.ac.cn）

● 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

GSI

MSU

RIKEN

Domestic

MPIK

Orsay

Yu. A. Litvinov

G. Audi

K.Blaum

T. Uesaka

H. Schatz B. A. Brown

CSR mass measurement collaboration

B. H. Sun F. R. Xu Y. Sun

Storage rings CSR at IMP

CSRe

SFC (K=69)SSC(K=450)

CSRm

RIBLL1 RIBLL2

CSR @ IMP

Storage rings CSR at IMP

CSR @ 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

22

11

Bqm

cL

T

ref

reft BBd

LdL)()(

2

v

v

qm

qm

T

T

tt

2

2

21

1

e-Cooler

Principle & method of Measurements

1985 - H. Wollnik, Y. Fujita, H. Geissel, G. Münzenberg, et al.

Injection ToF

v

v

qm

qm

T

T

tt

2

2

21

1

t v

v

t

2

2

1

Principle & method of Measurements

Isochronous Mass Spectrometry

Detector

TimingDetector

10 mm 9BeTarget

gt=1.395

IMS @ CSR

Some technique developments for IMS mass measurement in CSRe-Lanzhou

(2008 → present)

ToF Detectors used for IMS at ESR & CSR

Injection

ToF@CSRe

ToF

Thin Cfoil

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

Efficiency20%-70 %

Time resolutionSigma = 37 ps

IMS at CSR: high resolving power

IMS: Isochronous Mass Spectrometry

34Ar & 51Co close m/q

Phys. Lett. B 735,327 (2014)Another development …

58Ni beam: Charge & Frenquency Resolved IMS

Time vs Amplitude Analysis for: 51Co & 34Ar

Time vs Amplitude Analysis for: 51Co & 34Ar

This work ME(34Ar)= -18379(15) keVAME03: ME(34Ar)= -18377.2(4) keV

This work: ME(51Co)= - 27342 (48) keV

P. Shuai et al., Phys. Lett. B 735,327 (2014)

Time difference 1.63 (35) ps

0+

2+

4+

6+

8+

T1/2 = 71 msEx=2645 keV

Obtained from 30 turns

Both the mass and partial half-life are measured

simultaneously for T1/2 = 71 ms isomer in 94Ru.

It shows the capability of IMS

Period

In-ring decay

In-ring decay of T1/2 = 71 s Isomer in 94Ru

isomer

Cou

nts

Num

ber

of is

omer

Time (s)

v

v

qm

qm

T

T

tt

2

2

21

1

t v

v

t

2

2

1

Isochronous Mass Spectrometry

Double ToF IMS@IMP

2

1( )

1

n

iT T

STDEVn

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

iii TL

Double ToF IMS@IMP

t = 1.3~1.4

i

i

i

tii L

LLTTLT

0

2

2

00 1)(

%1.0

BB

Two ToFs: SimulationsWithout correction

With

With

out

With correction

Double ToF IMS@IMP

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, 112501 (2011)3.X. L. Tu et al., NIM A 654, 213 (2011)4.Y. H. Zhang et al., PRL 109, 102501 (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, 025104 (2014)8. W. Zhang et al., NIM A 756, 1 (2014) 9. B. Mei et al., Phys. Rev. C 89, 054612 (2014)10. P. Shuai et al., Phys. Lett. B 735,327 (2014)

Beams: 56Ni, 78Kr, 86Kr, 112Sn, 36Ar

Precision10-6~10-7

(20-200 keV)

Remeasured 27

Newly measured 26

Double ToF

Nuclides at the rp- & vp-process paths

np – process

C. Weber et al., Phys. Rev. C 78, 054310 (2008)V.-V. Elomaa et al., Phys. Rev. Lett. 102, 252501 (2011)E. Haettner et al., Phys. Rev. Lett. 106, 122501 (2011)F. Herfurth et al., Eur. Phys. J. A, 47,75 (2011)

CSRe (IMP, Lanzhou)

X. Tu et al., Phys. Rev. Lett. 106, 112501 (2011)

Slide from Klaus Blaum

Nuclear Astrophysics:

65As: on the waiting point nuclide 64Ge, PRL 106, 112501 (2011) 45Cr: on the Ca-Sc cycle in the rp-process Astrophys. J. Lett. 766, L8 (2013) 82Zr: on the reaction path of p-process at A=80-86 in progress

Nuclear Structure:

53Ni: on the isospin multiplet mass equation PRL 109, 102501 (2012) 51Co: on isospin non-conserving forces Phys. Lett. B 735,327 (2014) 52Co, 56Cu: np interaction at N=Z=28 closed shell 53Sc: 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

(65As)

-- Waiting Point in the rp-process of X-ray burst

Reaction pathLight curve

Element abundance

65As

Sp(65As) >-250 keV (AME2003)

Waiting point at 64Gein the Type I X-ray burst ?

Results from CSRe: (1) waiting point 64Ge

Sp(65As) = -90 (85) keV

2 s

Lig

ht

curv

e of

Typ

e I

x-ra

y b

urs

t

89%–90% of the reaction flow passesthrough 64Ge via proton capture indicating that: 64Ge is not a significant rp-process waiting point.

1 s

Ab

und

ance

of

burs

t as

hes

X.L. Tu et al., PRL 106, 112501 (2011)

Results from CSRe: (1) waiting point 64Ge

Impact of CSRe Mass Measurement

Mass Measurement of Tz=-3/2 Nuclei

(45Cr)

-- Test of Ca-Sc Cycle in rp Process

T=1.5 GKr=104 g/cm3

T=103 sec.

van Wormer et al., Astrophys. J. 432, (1994) 326

Results from CSRe: (2) Ca-Sc cycle

Precision mass of 45Cr 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

(82Zr)

-- 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 isuncertain 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-processat A=80-86 is determined

Impact of CSRe Mass Measurements

Mass measurement of Tz=-3/2 nuclei

(53Ni)

-- test of Isospin multiplet mass equation

N = Z

- 3/2

g.s

- 1/2

IAS

+ 1/2

IAS

+ 3/2

g.s

Neutron

Pro

ton

(A,T,Jp)

Degenerate if nocharge-dependent

Interaction, and DnH

corrected for.

- 3/2 - 1/2 + 1/2

+ 3/2

Charge-dependenteffects

M(A,T,Tz)=a(A,T)+b(A,T)Tz+c(A,T)Tz2

Any charge-dependent effects are two body interactions and be regarded as a perturbation.

Results from CSRe: (4) test IMME equation in pf shell

33

2333 ),(),(),(),,(),,( TATdTATcTATbATaTATM

Test the IMME: the case of A=33,T=3/2

Breakdown of the Isobaric Multiplet Mass Equation at A= 33, T=3/2F. Herfurth, PhysRevLett.87.142501(2001)

33

2333 ),(),(),(),,(),,( TATdTATcTATbATaTATM

d coeficients increase gradually up to A=53 for which d is 3.5s deviated from zero.

Test the IMME in fp shell nuclei

Y.H. Zhang et al., PRL 109, 102501 (2012)

Shell model calculations

C. Dossat et al., Nucl. Phys. A792 (2007) 18-86

Beta-delayed proton

63%5.4%

Mass Excesses uncertainty: 0.6 keV 25 keV 3. 4 keV 19 keV

53Mn gs 53Ni gs 53Fe IAS 53Co 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

(52Co and 56Cu)

--Behaviour of np interaction at 28 closed shell

Behaviour of np interaction around 208Pb L. Chen et al., Phys Rev Lett, 102, 122503(2009)

Proton Neutron

82126

np interaction strength depends on the overlap of their wave functions

Proton and neutron shell closure

208Pb56Ni

56Cu(29,27)

52Co(27,25)

Behaviour of np interaction around 56Ni

np interaction strength depends on the overlap of their wave functions

28

Impact of CSRe Mass Measurements

Mass Measurement of neutron-rich Nuclei

(53Sc … )

--On the new magic number at N=32

Results in Ti isotopes: N=32: shell gap, N=34: not shell gap

00+

15542+

1554

26754+

1121

31996+

524

61357+

2936

65398+

3340

404

6769(9+ )

230

7570(10 + )

8790(11+

)

50Ti

00+

17562+

27044+

33886+

58977+

64008+ 66299+

751610 +

879011+

GXPF1

00 +

10502+

1050

23184 +

1268

30296 +

711

4288(8 + )

1259

6693(10 + )

2405

8857

2164

9088

2395

231

52Ti

00 +

12132 +

24184 +

31036 +

45398+ 4750

7 +

61818 +

679010+

75109 +

953811+

1067212+

GXPF1

00 +

1495(2 +)

1495

2497(4 +)

1002

2936(6 +)

439

5111

2175

(7 + )

5459(8 + )

2523

348

5904(8 + )

2967

6187(9 + )

728284

6432(10+ )

245

54Ti

00 +

15092 +

26334+

31526 +

53847+

57708+

62088+

65639 + 679310

+

907511+

1048712+

GXPF1

00 +

1128(2 + )

1128

2289(4 + )

1161

2979(6 + )

690

((8 + ))

1230

56Ti

00+

15162+

25294+

30446+

8 + 5352

9+ 5387

693710 +

GXPF1

32

28

34

48Ti 50Ti 52Ti 54Ti 56Ti2

4

6

8

26 28 30 32 34 N

B(E

2,

) (1

00e2 f

m4 )

D.-C. Dinca et al., PRC 71 041302(R) (2005)

R.V.F. Janssens et al., PLB 546, 22 (2002) B. Fornal et al., PRC 70, 064304(2004)

Results from CSRe: (7) N=32 magic number

Results from CSRe: (7) N=32 magic number

D. Steppenbeck et al., Nature 502, 207 (2013)

In progress

New shell closure or magic number waspredicted 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 ms 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 spectrometrycollaborated with GSI+ Stochastic cooling

Schottky Pick-up

Summary and perspectives

Summary and perspectives

136Xe

124Sn

100Mo

86Kr

64Ni

48Ca

92Mo

58Ni

78Kr

112Sn

Continuing the mass measurements at both proton and neutron rich sides using IMS

CRYRING

FAIR

CSR@IMP

ESR@GSI

HESR

RI-RING@RIKEN

TSR@ISOLDEHIAF

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

1

2

3 4

56

78

9

Institute of Modern Physics, CAS, Lanzhou

Thank you for your attention !

Time vs Amplitude Analysis for: 51Co & 34Ar

This work ME(34Ar)= -18379(15) keVAME03: ME(34Ar)= -18377.2(4) keV

This work: ME(51Co)= - 27342 (48) keV

Tz=-3/2

Tz=-1

Tz = -1/2