Applications of Isochronous Mass Spectrometry (IMS) at HIRFL-CSR - - PowerPoint PPT Presentation

Applications of Isochronous Mass Spectrometry (IMS) at HIRFL-CSR

OUTLINE

• Introduction to Isochronous Mass Spectrometry
• Experimental results and techniques
• Summary

NuSTAR meeting 2015, GSI

Xiaolin Tu 04/03/2015

Mass Excess

Nuclear mass







A i i

m N Z M

1

) , (

Interaction

<10-10 Metrology: fundamental constants, CPT 10-9−10-11 Atomic physics: binding energy, QED 10-8 Weak interaction studies: CVC, CKM 10-7−10-8 Nuclear models and formulas: IMME 10-7 Astrophysics: r, rp-process, waiting points 10-7−10-8 Nuclear fine structure: deformation, halos 10-6 Nuclear physics: shells, sub-shells, pairing 10-5−10-6 Chemistry: identification of molecules

Mass uncertainty

Field of application

• K. Blaum et al., Phys. Rep. 425, 1 (2006)1

Short life, low production cross-section Many masses of nuclides still are unknown

• G. Audi et al.,Chin. Phys. C36 (2012)1157

Chart of the nuclides displaying the accuracy ’u’ of masses

38Ca (T1/2 = 440ms)

1930 1940 1950 1960 1970 1980 1990 2000 2010 10

• 12

10

• 11

10

• 10

10

• 9

10

• 8

10

• 7

10

• 6

10

• 5

10

• 4

10

• 3

Mass Uncertainty m/m

year

28Si

PTMS Reaction Q RF Spectrometers Mass Spectrographs

single ion ion cloud

100 eV 100 keV 1 eV 10 eV 1 keV 1 MeV

δE (A=100)

10 keV

Picture obtained from Klaus Blaum‘s talk

. . . . . .

• Penning Trap
• MR TOF
• Time-of-flight-Brho Mass measurement
• Schottky mass spectrometry
• Isochronous mass spectrometry

Picture obtained from M.Saidur Rahaman’thesis

Proposeed Proposeed by H. by H. Wollnik Wollnik about 30 years ago. about 30 years ago.

   

v v q m q m f f

t t

              

2 2 2

1 1   

t v/v  10-3

Mass resolving power~1.5×105

   

v v q m q m f f

t t

              

2 2 2

1 1   

Mass resolving power ~ 200 000 (FWHM)

I Institute of M Modern P Physics (IMP)

LanZhou city

IMP IMP

CSRm CSRm CSRe CSRe RIBLL2 RIBLL2

DT

HIRFL-CSR

Detector

IMS  Low energy beam Accelerated to high energy (CSRm) PF

striper

TOF detector

Fast time detector

• B. Mei, et al., NIM A624,109(2010)

Time resolution ~50ps, Efficency~20%-70% signal

1mm

Advanced Performance TOF 1 Mohm 3 Mohm 3 Mohm

Optimize the structure of MCP

Improve transmission of high frequency signal

Rising time ~220 ps

faster resistor

• W. Zhang, et al., NIMA 756, 1(2014)

Anode MCP

Time resolution is ~ 18 ps

E=180V/mm E=180V/mm

• W. Zhang, et al., NIMA 756, 1(2014)

C foil MCP Anode

• M. Matos, Ph.D. Thesis, JLU Giessen, 2004.
• X. L. Tu, et al., NIMA654,213(2011)

Data analysis

ion1 ion2

Identification of ions

19Ne 21Na 23Mg 25Al 27Si 29P 31S 33Cl 35Ar 71Kr

51Co27+and 34Ar18+ ions have very close mass to charge ratios

[(m/q)/(m/q)~5×10-6].

They can not be resolved by their revolution time.

Revolution time C foil Storage ring e- MCP Detector Oscilloscope

Amp∝ electron number ∝ Q2

bigger more higher

Particle identification

• P. Shuai et al., Phys. Lett. B735, 327(2014)

Particle identification with Revolution time and Average amplitude

Stability of magnetic field Improve power supply

2011 2009

CSRe CSRe

difference

A mass Resolving Power(m/∆m) ~ 1.7×105 ~7ns

In-ring decay of the 94Ru isomer

T1/2 = 71(4) s Ex=2645 KeV

94Ru g.s 94Ru isomer

   

v v q m q m f f

t t

              

2 2 2

1 1   

m/q(t)=a0+a1T+…+a2Tn

Mass measurements at HIRFL-CSR

Since 2007

• Nucl. Instr. Meth. A624, 109 (2010)
• Nucl. Instr. Meth. A654, 213 (2011)
• Phys. Rev. Lett. 106, 112501 (2011)
• J. Phys. G 41, 025104 (2014)
• Phys. Rev. Lett. 109,102501(2012)
• Astro. J. Lett. 766, 8 (2013)
• Phys. Lett. B735, 327(2014)

Under analysis…

#200910 #201102 #201201

78Kr+Be 58Ni+Be 86Kr+Be

n=1.11 (1±0.13)

<10-10 Metrology: fundamental constants, CPT 10-9−10-11 Atomic physics: binding energy, QED 10-8 Weak interaction studies: CVC, CKM 10-7−10-8 Nuclear models and formulas: IMME 10-7 Astrophysics: r, rp-process, waiting points 10-7−10-8 Nuclear fine structure: deformation, halos 10-6 Nuclear physics: shells, sub-shells, pairing 10-5−10-6 Chemistry: identification of molecules

Mass uncertainty

Field of application

PRC79,045802 (2009)

To determine which degree 64Ge is a waiting point, need to measure the mass of 65As.

64Ge is a waiting point ?

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

• X. L. Tu, et al., PRL106,112501(2011)

ME(65As)=−46937(85) keV Q=90(85) keV

64Ge(p, r)65As

• H. Schatz’s calculation

Coulomb displacement energy(CDE), △Ec, is the difference of binding energy of mirror nuclei.

  

  B B Ec

For charged spherical nucleus, △Ec can be expressed as a linear function of Z/A1/3 However, for a deformed nucleus with quadrupole deformation 2, it’s non-linear(second order polynomial)

This systematic tendency indicates the spherical shape starts to change around A=65

• X. L. Tu, et al., J. Phys. G 41 (2014) 025104

58Ni+Be

Isobaric Multiplet Mass Equation (IMME) A correction, d(A,T)Tz3 of IMME is proportional to Z.

3 3 2 3 3 3

) , ( ) , ( ) , ( ) , , ( ) , , ( T A T d T A T c T A T b A T a T A T M    

d parameters 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., PRL109, 102501(2012)

• Y. H. Zhang, et al., PRL109, 102501(2012)

300 turns

Revolution time C foil Storage ring e- MCP Detector Oscilloscope

D etection Efficency ~20%-70% 200us ~ 300 turn

Odd-Even Staggering of Yields

78Kr(~500MeV/u)+Be(15mm)

A=2Z-1

• B. L. Tracy et al., Phys. Rev. C 5, 222 (1972).

• B. Mei, et al., Phys. Rev. C89, 054612(2014)

Particle-Emission Threshold Energy (PETE) is the smallest value from either the neutron or the proton separation energy.

94Ru g.s 94Ru isomer

Projectile fragmentation → Isomer A mass Resolving Power(m/∆m) ~ 1.7×105

Isomeric Yield ratio

• verestimate

underestimate

• M. Bowry,et al., Phys. Rew. C 88, 024611 (2013)
• Z. Podolyak et al., Phys. Lett. B632, 203 (2006)

Different projectiles (58Ni, 78Kr, 84Kr, 112Sn) have been used to produce the same isomeric state, e.g., the high-spin 19/2 state in 53Fe.

MASS LOSS: Ap-A’f

Rexp/Rth>1

Rexp/Rth<1 Overestimate

Underestimate

58Ni 78Kr 84Kr 112Sn

53Fe, isomeric ratios, J=19/2

The production probability as a function of spin for 53Fe

Small mass loss ~ higher spin ~ underestimate Large mass loss ~ lower spin ~ overestimate

Observed by Z. Podolyak

• Z. Podolyak et al., Phys. Lett. B632, 203 (2006)

Underestimate Overestimate

The overestimation/underestimation is not only dependent

• n the spin, but also depends on the mass loss

~2 ps

   

v v q m q m f f

t t

              

2 2 2

1 1   

v q m B   

Acceptance dp/p~0.1% dv/v~0.05% V V0

   

v v q m q m f f

t t

              

2 2 2

1 1   

18m Time detector 1 Time detector 2

Trev

V=L/(T V=L/(T1

1-

• T

T2

2)=L/TOF

)=L/TOF

1、HIRFL-CSR can be operated as IMS 2、Improvement of technique

• Amplitude-revolution time identification
• High time resolution detector

3、Mass experimental results

• 64Ge is not a significant rp-process waiting point
• Spherical shape starts to change around 65As
• Breakdown of IMME at A=53,T=3/2

4、Reaction mechanism study with IMS

• Odd-Even Staggering of yields
• Isomeric ratios

Summary

Thanks for your attention

Xu, H. S., Audi, G., Blaum, K., Brown, B. A., Chen, X. C., Du, C. M., Geng, P., Hu, Z. G., Huang, W. X., Jia, G. B., Jin, S. L., Litvinov, S. Litvinov, Yu. A., Liu, L. X., Liu, Y., Ma, X., Mao, R. S., Mei, B., Schatz, H., Shuai, P., Sun, B. H., Sun, Y., Sun, Z. Y., Suzuki, H., Tang, S. W., Tu, X. L., Typel, S., Uesaka, T., Wang, J. S., Wang, M., Wang, S. T., Xia, J. W., Xiao, G. Q., Xu, X., Yamaguchi, T., Yamaguchi, Y., Yan, X. L., Yang, J. C., Ye, R. P., Yuan, Y. J., Zang,

• Y. D., Zhan, W. L., Zhang, X. Y., Zhang, Y. H., Zhao, H. W.,

Zhao, T. C., Zhou, X. H……………………