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

NuSTAR meeting 2015, GSI Applications of Isochronous Mass Spectrometry (IMS) at HIRFL-CSR OUTLINE • Introduction to Isochronous Mass Spectrometry • Experimental results and techniques Xiaolin Tu • Summary 04/03/2015

A   ( , ) M Z N m i  1 i Nuclear mass Interaction Mass Excess Mass uncertainty Field of application 10 -5 − 10 -6 Chemistry: identification of molecules Nuclear physics: shells, sub-shells, pairing 10 -6 10 -7 − 10 -8 Nuclear fine structure: deformation, halos 10 -7 Astrophysics: r, rp-process, waiting points 10 -7 − 10 -8 Nuclear models and formulas: IMME Weak interaction studies: CVC, CKM 10 -8 10 -9 − 10 -11 Atomic physics: binding energy, QED <10 -10 Metrology: fundamental constants, CPT K. Blaum et al., Phys. Rep. 425, 1 (2006)1

Short life, low production cross-section Many masses of nuclides still are unknown Chart of the nuclides displaying the accuracy ’u’ of masses G. Audi et al.,Chin. Phys. C36 (2012)1157

Picture obtained from Klaus Blaum‘s talk -3 10 δ E 38 Ca ( T 1/2 = 440ms) 28 Si -4 10 ( A =100) -5 10 1 MeV Mass Uncertainty  m / m Reaction Q -6 10 100 keV PTMS Mass -7 10 keV 10 Spectrographs -8 1 keV 10 ion cloud RF -9 100 eV 10 single ion Spectrometers 10 eV -10 10 -11 1 eV 10 -12 10 1930 1940 1950 1960 1970 1980 1990 2000 2010 year

• Penning Trap • MR TOF • Time-of-flight-Brho Mass measurement • Schottky mass spectrometry • Isochronous mass spectrometry . . . . . . Picture obtained from M.Saidur Rahaman’thesis

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

Mass resolving power~1.5 × 10 5  v/v  10 -3          2 1 f m q v      1       2 2   f m q v t t  t

         2 1 f m q v      1       2 2   f m q v t t Mass resolving power ~ 200 000 (FWHM)

I nstitute of M M odern P P hysics ( IMP ) I LanZhou city IMP IMP

CSRe CSRe RIBLL2 RIBLL2 CSRm CSRm

HIRFL-CSR Low energy beam TOF detector Detector DT Accelerated to high energy (CSRm) IMS    striper PF

Fast time detector signal Time resolution ~50ps, Efficency~20%-70% B. Mei, et al., NIM A624,109(2010)

Improve transmission of high frequency signal Advanced Performance TOF 1 Mohm 3 Mohm faster 3 Mohm MCP Rising time ~220 ps 1mm resistor Anode Optimize the structure of MCP W. Zhang, et al., NIMA 756, 1(2014)

E=180V/mm E=180V/mm C foil MCP Time resolution is ~ 18 ps Anode W. Zhang, et al., NIMA 756, 1(2014)

Data analysis ion1 ion2 M. Matos, Ph.D. Thesis, JLU Giessen, 2004. X. L. Tu, et al., NIMA654,213(2011)

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

51 Co 27+ and 34 Ar 18+ ions have very close mass to charge ratios [  (m/q)/(m/q)~5 × 10 -6 ]. They can not be resolved by their revolution time.

e- C foil MCP Revolution time Detector Oscilloscope Storage ring Amp ∝ electron number ∝ Q 2 higher more bigger

Particle identification Particle identification with Revolution time and Average amplitude P. Shuai et al., Phys. Lett. B735, 327(2014)

Stability of magnetic field 2009 Improve power supply CSRe 2011 CSRe

difference

A mass Resolving Power( m/ ∆ m ) ~ 1.7 × 10 5 ~7ns

In-ring decay of the 94 Ru isomer T 1/2 = 71(4)  s 94 Ru g.s Ex=2645 KeV 94 Ru isomer          2 1 f m q v      1       2 2   f m q v t t

m/q(t)=a 0 +a 1 T+…+a 2 T n

Mass measurements at HIRFL-CSR Since 2007 #200910 Nucl. Instr. Meth. A624, 109 (2010) 78 Kr+Be 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) #201102 58 Ni+Be Under analysis… #201201 86 Kr+Be

 n =1.11 (1 ± 0.13)

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

To determine which degree 64 Ge is a waiting point, need to measure the mass of 65 As. PRC79,045802 (2009)

64 Ge is a waiting point ? 64 Ge(p, r) 65 As ME( 65 As)= − 46937(85) keV Q=90(85) keV H. Schatz’s calculation 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 . X. L. Tu, et al., PRL106,112501(2011)

Coulomb displacement energy(CDE), △ Ec , is the difference of binding energy of mirror nuclei.     Ec B B  For charged spherical nucleus, △ Ec can be expressed as a linear function of Z/A 1/3 However, for a deformed nucleus with quadrupole deformation  2 , it’s non-linear(second order polynomial)

X. L. Tu, et al., J. Phys. G 41 (2014) 025104 This systematic tendency indicates the spherical shape starts to change around A=65

58Ni+Be Isobaric Multiplet Mass Equation (IMME) A correction, d(A,T)T z3 of IMME is proportional to Z  .

Test the IMME in fp shell nuclei     2 3 ( , , ) ( , , ) ( , ) ( , ) ( , ) M T A T a T A b T A T c T A T d T A T 3 3 3 3 d parameters increase gradually up to A=53 for which d is 3.5s deviated from zero. Y. H. Zhang, et al., PRL109, 102501(2012)

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

C foil e- 300 turns MCP Revolution time Detector Oscilloscope Storage ring D etection Efficency 200us ~ 300 turn ~20%-70%

Odd-Even Staggering of Yields 78 Kr(~500MeV/u)+Be(15mm) A=2Z-1

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

Particle-Emission Threshold Energy (PETE) is the smallest value from either the neutron or the proton separation energy. B. Mei, et al., Phys. Rev. C89, 054612(2014)

Projectile fragmentation → Isomer A mass Resolving Power( m/ ∆ m ) ~ 1.7 × 10 5 94 Ru isomer 94 Ru g.s

Isomeric Yield ratio

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

MASS LOSS: A p -A’ f 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.

53 Fe, isomeric ratios, J=19/2 R exp /R th >1 Underestimate R exp /R th <1 Overestimate 112 Sn 84 Kr 78 Kr 58 Ni

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) The overestimation/underestimation is not only dependent on the spin, but also depends on the mass loss Underestimate Overestimate The production probability as a function of spin for 53Fe

         2 1 f m q v      1       2 2   f m q v t t m    B v q ~2 ps

        2  1 f m q v      1       2 2   f m q v t t Acceptance dp/p~0.1% dv/v~0.05% V 0 V 0

T rev Time detector 1 Time detector 2 2 )=L/TOF )=L/TOF 18m T 2 -T 1 - V=L/(T 1 V=L/(T

Summary 1 、 HIRFL-CSR can be operated as IMS 2 、 Improvement of technique • Amplitude-revolution time identification • High time resolution detector 3 、 Mass experimental results • 64 Ge 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

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……………………