a(A,T)+ - IMP-CUSTIPEN workshop on

Special section on mass measurements
1.
Meng Wang, Mass measurements for short-lived nuclei at CSReLanzhou
2.
3.
Rui-Jiu Chen, A simulation of the isochronous mass spectrometry
Chao-Yi Fu, Improvement of ToF detector and applications in
Double ToF experiment
4.
Xing Xu, Direct Mass Measurements of Neutron-rich 86Kr Projectile
Fragments and the Persistence of Neutron Magic Number N = 32
in Sc Isotopes
Yuan-Ming Xing, Mass measurements of 112Sn Fragments at CSReIMP
Qi Zeng, Half-life measurement of 94mRu44+ at HIRFL-CSR
5.
6.
7.
Xin-Liang Yan, Schottky mass measurements of 152Sm projectile
fragments at ESR
Mass Measurements for
Short-lived Nuclei
at CSRe-Lanzhou
Meng Wang
Institute of Modern Physics, CAS
CSRe mass measurement collaboration
H. S. Xu, Y. H. Zhang, M. Wang, R. J. Chen, X. C.Chen, C. Y. Fu, B. S. Gao, P. Shuai,
M.Z. Sun, X. L.Tu, Y.M. Xing, X. Xu, X. L. Yan, Q. Zeng,
X. H. Zhou, Y. J. Yuan, J. W. Xia, J. C. Yang, Z. G. Hu, X. W. Ma, R. S. Mao, B. Mei,
G. Q. Xiao, H. W. Zhao, T. C. Zhao, 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)
Outline
•
•
•
•
Motivation and background
Method and technical improvements
Results and discussions
Summary
Motivation: why do we measure nuclear masses?
Mass → binding energy → interaction
= N×
+Z×
－ binding energy
Nuclear physics
Nuclear astrophysics
Atomic physics
Atomic energy
Fundamental symmetries
Metrology
…
Background: current status of mass measurements
predicted
~7000
discovered ~3200
mass known ~2400
Background: worldwide activities
JYFL
MSL
GANIL
JGU
JINR
GSI
TRIUMP
CIAE
RIKEN
IAEA
CERN
MSU
ORNL
LBL
IMP
Main institutions of nuclear research
Facilities for direct mass measurements
ANL
BNL
FSU
Background: HIRFL-CSR research facility
Research aims:
establish the IMS technique; measure nuclear masses;
study the associated physics
CSRe
RIBLL1
RIBLL2
RIBs at tens of AMeV
RIBs at hundreds of AMeV
CSRm
1000 AMeV (H.I.),  2.8 GeV (p)
Method and
technical improvements
Procedure of mass measurements
SSC
SFC
DT
CSRe
CSRm
TOF
detector
Principle
T=L/v
Bρ=m/q βγc
m q 
(  )
2 v

 
m q 
(  )
v
2
T
T
Principle : isochronous mass spectrometry
T=L/v
Bρ=m/q βγc
L
1 ( B )
 2
L
 t ( B )
T L v
1
1 p


( 2  2)
T
L
v
t 
p
First mass measurement at CSRe
M. Wang et al., Int. J. Mod. Phys. E, Vol. 18, No. 2 (2009) 352-358
Correction for drift of the magnetic fields
arXiv:1407.3459
Resolving power
ps
m
m( FWHM )
 250,000
Principle of double-TOF IMS
614.698
614.697
614.696
614.695
614.694
 v
T   2
  2  1
T
t
 v
614.693
614.692
-0.15 -0.1 -0.05 -1E-16 0.05
0.1
0.15
Double-TOF IMS
Two ToF detectors:
ds=18 m
Charge & Frequency Resolved IMS
34Ar
& 51Co
close m/q
Charge & Frequency Resolved IMS
Charge & Frequency Resolved IMS
PL B 735 (2014) 327
Results and discussions
Overview of experimental results
Beams: 78Kr,
58Ni, 86Kr, 112Sn, 58Ni, 36Ar
X. L. Tu et al., PRL 106, 112501 (2011)
Y. H. Zhang et al., PRL 109, 102501 (2012)
X. L. Yan et al. ApJ 766, L8 (2013)
P. Shuai et al., PL B 735,327 (2014)
H. S. Xu et al., IJMS 349, 162 (2013)
Precision
10-6~10-7
(20-200 keV)
Double
TOF
Improved precision
Measured first time
Nuclear masses in astrophysics
X-ray
burst
Companion
star
Neutron star
R. Giacconi
2002 Nobel
Mass values of short-lived nuclei are important input
parameters to study rp-process
Results from CSRe: (1) waiting point 64Ge
Waiting point at 64Ge
in the Type I X-ray burst ?
65As
Sp(65As) >-250 keV (AME2003)
Reaction path
Light curve
Element abundance
Results from CSRe: (1) waiting point 64Ge
Abundance of burst ashes
Light curve of Type I x-ray burst
X.L. Tu et al., PRL 106, 112501 (2011)
2s
1s
Sp(65As) = 90 85 keV
89%–90% of the reaction flow passes
through 64Ge via proton capture
indicating that:
64Ge is not a significant rp-process
waiting point.
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: (3) test IMME in pf shell
Proton
Degenerate if no
charge-dependent
Interaction, and nH
corrected for.
Charge-dependent
effects
(A,T,Jp)
- 3/2
- 1/2
+ 1/2
+ 3/2
Neutron
M(A,T,Tz)=a(A,T)+b(A,T)Tz+c(A,T)Tz2
Any charge-dependent effects are two body interactions
and can be regarded as a perturbation.
Results from CSRe: (3) test IMME in pf shell
M(A,T,T3)=a(A,T)+b(A,T)T3+c(A,T)T32
+ d(A,T)T33
Mass measurements of 41Ti, 45Cr,
49Fe, and 53Ni at CSRe
d coefficients increase gradually
up to A=53 for which d is 3.5s
deviated from zero.
Cannot be explained by existing theories
PRL 109, 102501 (2012)
Results from CSRe: (4) test INC
The obtained results point to
the necessity to include INC
interactions in the calculations
of fp-shell nuclei.
Rui-Jiu Chen, A simulation of the
isochronous mass
spectrometry
Chao-Yi Fu, Improvement of ToF
detector and applications
in Double ToF experiment
Xing Xu, Direct Mass Measurements of
Neutron-rich 86Kr Projectile Fragments
Yuan-Ming Xing, Mass measurements of
112Sn Fragments at CSRe-IMP
Qi Zeng, Half-life measurement of 94mRu44+
at HIRFL-CSR
Xin-Liang Yan, Schottky mass measurements of 152Sm projectile fragments at ESR
Thank you for your attention!