Single-Particle Spectroscopy of 133 Sn via the (d,p) reaction in - PowerPoint PPT Presentation

Single-Particle Spectroscopy of 133 Sn via the (d,p) reaction in inverse kinematics Kate L. Jones University of Tennessee

Shell model fingerprints on the galaxy Pfeiffer, Kratz, Thielemann and Walters, Nuc. Phys. A 693 282 (2001)

The rapid neutron capture (r-)process large deviations in r-process path at shell closures (n, γ ) ( γ ,n) β - decay Z N

What we can learn from transfer reactions • Q-value • mass. Counts • excitation energies. • Angular distributions of recoils • l -value of transferred nucleon. • combined with calculations gives spectroscopic Q value (MeV) factor.

Opportunities at the HRIBF HRIBF yields N=82 Previous studies close to N = 50 N=50 J.S. Thomas et al Fission fragment beams Phys. Rev. C 71 , 021302 (2005) Production via p-induced fission on U Phys. Rev. C 76 , 044302 (2007) gives access to n-rich nuclei close to N=50,82

Opportunities at the HRIBF HRIBF yields N=82 Current studies close to N = 82 and Z = 50 N=50 r-process close to shell closure Fission fragment beams  Low level density Production via p-induced fission on U  Small capture cross section gives access to n-rich nuclei close to  Statistical model not reliable N=50,82  Direct capture important

Transfer measurements around 132 Sn 124 Sn 130 Te 131 Sn 135 Te 133 Sn Te 16 O Sb Z = 50 In Stable Doubly magic N = 82 Neutron transfer e.g. (d,p), sensitive probe of single-particle structure. Can extract energies, l -values and spectroscopic factors. Reaction is selective.

Magicity of 132 Sn ?

What is a Spectroscopic Factor?  Specific Example 10 Be(g.s.) ⊗ 2 s 1/2 + A 10 Be(2 + ) ⊗ 1d 5/2 + ... 11 Be(g.s.) = A 2 s 1/2 1d 5/2  Nuclear Reaction Theory s.p. radial overlap function 2 Spectroscopic S  sj = A  sj u  sj ( r ) = A  sj ν  sj ( r ) where Amplitude  Nuclear Reaction Experiment Normalized WF d σ exp / d Ω exp = S lsj d σ DWBA / d Ω

132 Sn(d,p) photo

133 Sn Q-value spectrum

133 Sn Angular Distributions Theory from Filomena Nunes (NSCL)

Values for 133 Sn Ex (keV) J π Configuration SF C 2 (fm -1 ) 0 7/2 - 132 Sn gs ⊗ ν f7/2 0.86 ± 0.16 0.64 ± 0.10 854 3/2 - 132 Sn gs ⊗ ν p3/2 0.92 ± 0.18 5.61 ± 0.86 1363±31 (1/2) - 132 Sn gs ⊗ ν p1/2 1.1 ± 0.3 2.63 ± 0.43 2005 (5/2) - 132 Sn gs ⊗ ν f5/2 1.1 ± 0.2 (9 ± 2) × 10 -4

Checking optical potentials “local” optical potential from Strömich et al Phys. Rev C 16 , 2193 (1977). “global” optical potentials: deuteron Lohr and Haeberli Nucl. Phys. A232 381 (1974). proton Varner et al. Phys. Rep 201 57 (1991).

Magicity of 132 Sn 5 5 E 2+ (MeV) (a) (c) (a) (b) Sn 3#)%$ !/.6$ Pb 4 2.)%$ !/.6$ !/0!$ 5#.)%$ 3 #/!($ 4##)%$ 2 1-)%$ !/-%$ 1 #%0$ 0 5 0 S 2n (MeV) (b) (c) (d) '.)%$ #/#$ 20 ,-)%$ #/#$ *#)%$ !/-%$ *+)%$ 10 '()%$ !/&0$ &%$ 0 0 ! "%!$ "#!$ K.L. Jones et al. Nature 465 454 (2010) N-N magic

r-process sensitivity studies. 30 30 %age Abundance Change %age Abundance Change 20 20 130 Sn Rate x 10 132 Sn Rate x 10 10 10 0 0 -10 -10 -20 -20 -30 -30 100 140 180 100 140 180 A A Simulations of the r-process show global sensitivity to the 130 Sn(n, γ ) rate, in contrast to the 132 Sn(n, γ ) rate. Taken from J. Beun, et al J. Phys. G 36 025201 (2009)

r-process sensitivity studies. 30 30 %age Abundance Change %age Abundance Change 20 20 130 Sn Rate x 10 132 Sn Rate x 10 10 10 0 0 -10 -10 -20 -20 -30 -30 100 140 180 100 140 180 A A Build up of material at 130 Sn, due to long half life (4 min) compared to 130 Cd and 130 In (~ 1 sec). (n, γ )’s take material out of mass 130 into 131, and also soak up neutrons. Taken from J. Beun, et al J. Phys. G 36 025201 (2009)

Rauscher et al., PRC 57 , 2031 (1998) Direct Capture on 130 Sn 130 Sn FRDM HFB RMFT Cross section depends largely on predicted binding energies for 3p s. p. states. No s. p. states identified previously in 131 Sn.

2 H( 130 Sn,p) 131 Sn Fwd ORRUBA #1, MCP coinc., narrow TAC window Q-value for 130Sn(d,p)131Sn 4666(33) 4015(23) 3413(19) 2661(18) 131 Sn* (keV) Previously unobserved p- wave states important to neutron direct capture at late times in r-process. Statistical errors in ( ) . Systematic error: ~30 keV Q gs = 3.022 MeV R. L. Kozub, 238 th ACS National Meeting, 16 August 2009

131 Sn Preliminary angular distribution Prelim 5 4679(41) 131 Sn E x (MeV) 4018(28) 4 3417(23) 3 2680(23) 2 1 0 131 Sn 131 Sn(d,p) 130 Sn

Near-term future: fission fragments  (d,p) measurements: 126 Sn and 128 Sn  completing n-rich tin chain  understanding systematics  (d,p) measurement on 80 Ge  r-process sensitivity to nuclei to the west of the shell closure  Neutron transfer using ( 9 Be, 8 Be) on 130 Sn  pinning down the energies of states in 131 Sn

Where next - with HRIBF upgrade

Thanks to ….. UT-Knoxville: K. Y. Chae, R. Kapler, Z. Ma, B. H. Moazen, K. T. Schmitt TTU: R.L. Kozub, J. F. Shriner, Jr, S. V. Paulauskas, D. J. Sissom ORNL: D. W. Bardayan, F. Liang, C. D. Nesaraja, D. Shapira, M. S. Smith Rutgers U: J. A. Cizewski, R. Hatarik, S. D. Pain, P. D. O’Malley, W. A. Peters LSU: J.C. Blackmon ORAU: C. Matei Ohio U: A. Adekola UND: J. J. Kolata, A. Roberts U. Mich.: A. M. Villano Surrey: T. P. Swan, W. A. Catford, C. Harlin, N. Patterson, J. S. Thomas, S. M. Brown CSM: K. Chipps, U. Greife, L. Erikson, R. J. Livesay Furman: A. Gaddis IFJ PAN: W. Krolas EWU: K. I. Hahn NSCL/MSU: F. Nunes