Approaching 78 Ni Along the N=50 Line M.P. Carpenter Argonne National Laboratory
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Approaching 78 Ni Along the N=50 Line M.P. Carpenter Argonne National Laboratory INPC2007 June 6, 2007 • Studies with Gammasphere on neutron rich N~50 nuclei populated in deep inelastic collisions (DIC) using an 82 Se beam on 208 Pb and 238 U thick targets - Results on 84 Se and 82 Ge (N=50) - Results on 74 Zn (close lying 6 + states).
description
Approaching 78 Ni Along the N=50 Line M.P. Carpenter Argonne National Laboratory. Studies with Gammasphere on neutron rich N~50 nuclei populated in deep inelastic collisions (DIC) using an 82 Se beam on 208 Pb and 238 U thick targets Results on 84 Se and 82 Ge (N=50) - PowerPoint PPT Presentation
Transcript of Approaching 78 Ni Along the N=50 Line M.P. Carpenter Argonne National Laboratory
Approaching 78Ni Along the N=50 Line
M.P. CarpenterArgonne National Laboratory
INPC2007
June 6, 2007
• Studies with Gammasphere on neutron rich N~50 nuclei populated in deep inelastic collisions (DIC) using an 82Se beam on 208Pb and 238U thick targets
- Results on 84Se and 82Ge (N=50)
- Results on 74Zn (close lying 6+ states).
• Spontaneous fission sources 252Cf, 248Cm• Induced fission of actinide targets.• Deep Inelastic Collisions (DIC)• Fusion Evaporation (evaporated charged particle
channels).
How do we access neutron rich isotopes at Gammasphere
Distribution of fission fragments from the spontaneous fission of 252Cf.
Results from Gammasphere DIC 48Ca + 238U
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
3228 34
1129
R.V.F. Janssens et al., PLB 546, 22 (2002) B. Fornal et al., PRC 70, 064304 (2004)
Is 78Ni doubly magic?
T. Otsuka et al.,
Phys. Rev. Lett. 95, 232502 (2005)
28
50
82
28p3/2
f5/2
p1/2
g9/2
d5/2
g7/2
s1/2
h11/2
d3/2
f7/2
40
Neutron States
N=82
N=50
• Neutron magic-numbers at N=50 and N=82 play an important role in determining the r-process path.
Pushing towards 78Ni along the N=50 line?
Experimental Details
82Se (610 MeV) + 238U and 208Pb thick targets
with Gammasphere
Deep Inelastic excitation
(1) 82Se + 2n + 0p → 84Se(2) 82Se + 2n - 2p → 84Ge(3) 82Se – 4p – 4n → 74Zn
Gammasphere at ATLAS : The Present
FMA StationStand Alone Station
Results on 84Se
• 3 recent publications on 84Se level structure – DIC (Legnaro), induced fission (Orsay), 252Cf spontaneous fission (Vanderbilt).
• All results see only up to 1st 7+ state.
• 82Se + 238U with Gammasphere sees up to (12+)
0 500 1000 1500 2000ENERGY (keV)
0
50
100
150
200
250
300
350
400
CO
UN
TS
84Se-fig1.spe
16
5.4
62
5.1
70
4.5
86
9.9
92
6.1
12
48
.6
14
15
.6
15
81
.01
62
8.9
Gate: 1455-1087
RadWare84Se.ps, created 26-Feb-07 09:38:23
0
2
4
65
8
10
5
7
12
7
7
9
7
1455
667
1580
165
1087
1630
1249
1271
626
1362
1415
331
816
20851920
1197
869
926
704
84Se
(12+)
(10+)
(8+)
(7+)
(9+)
(7+)
(7+)
(5+)
6+
7+
4+
0+
2+
What is reported for 82Ge
decay of 82GaP. Hoff, B. Fogelberg,
Nucl. Phys. A 368, 210 (1981)Y.H. Zhang et. al.,
Phys. Rev. C 70, 024341 (2004)
82Se + 190Os DIC
82Ge
Gate on the 2+-0+ transition in 82Ge
5/2
7/2
9/2
11/2
13/2
15/2
1578
681
1267
564
1348
87Kr
0 500 1000 1500ENERGY (keV)
0
500
1000
1500
2000
2500
CO
UN
TS
*101
82Ge-1348-gate.spe 322.
735
8.9
564.
468
1.6
868.
3
940.
6
1240
.212
66.2
1577
.3
Gate: 1348 keV*
*
**
*
*
*
* 64Ni
* 87Kr8
66
94
0
?
What’s in coincidence with the 1348 and 940?
0 500 1000 1500ENERGY (keV)
0
50
100
150
CO
UN
TS
82Ge-938-1348.spe
646.
3
939.
1
Gate:938-1348
0
2
4
6
5
1348
939
941647
294
From 82Ge.gls82Ge50
(6+)
(4+)
(5+)
Level Systematics and Shell Model
A. F. Lisetskiy et al., Phys. Rev. 70, 044314 (2004).
N=50 Isotones
0
2
4
65
8
10
5
7
12
7
7
9
7
0
2
4
6
5
1455
667
1580
165
1087
1630
1249
1271
626
1362
1415
331
816
20851920
1197
869
926
704
1348
939
940647
293
84Se 82Ge
E = 475 keV
(6+)
(5+)
(4+)
2+
0+
(7+)
(7+)
(7+)
(9+)(10+)
(12+)
New T=1 effective interactions for the f5/2 p3/2 p1/2 g9/2 model space
82Ge(d,p) and 82Ge at HRIBF
2H(82Ge,p)83Ge
1/2+
Expt
0.5
1.0
Ex
(Me
V)
5/2+
TheoryJ.S. Thomas et al., Phys. Rev. C 71, 021302 (2005)
E. Padilla-Rodel et al., Phys. Rev. Lett. 94, 122501 (2005)
82Ge
1348 keV
82Ge Couloumb Excitation
New levels in 72,74Zn
A. Hecht et al., to be submitted to Phys. Rev. C
A4 = 0.0267(0.0256)A2 = -0.0756(0.0181)
1064(E2)/304(E1)
cos(x)
W(x)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
A4 = 0.0534(0.0210)A2 = 0.1097(0.0150)
1064(E2)/610(E2)
cos(x)
W(x)
0.0 0.1 0.2 0.3 0.4 0.5 0.6 0.7 0.8 0.9 1.00.80
0.85
0.90
0.95
1.00
1.05
1.10
1.15
Angular Correlations
E2-E1
E2-E2
Positive parity levels in Zn isotopes Exp. Vs. Theory
Calculations by A. J. Lisetskiy (JJ4APN)
Close lying 6+ States in 72,74Ni
A. J. Lisetskiy et al., Phys. Rev. C 70, 044314 (2004).
Summary
• Data on N=50 nuclei near 78Ni are becoming available
• Results are not entirely consistent with shell model.
- Important measurement 2+ excitation energy in 78Ni (direct indication if Z=28 gap has closed).
• Our data is rich – new information on odd-A nuclei e.g. 83As, 72,74Zn
• Also measured DIC with 64Ni + 208Pb, 238U (N. Hoteling – thesis)
• Improvements to measurement
- Mass Selectivity (PRISMA at Legnaro, Chico at Gammasphere)
- One -ray is sometimes enough to get started but two is better.
Collaborators on 82Se DIC
M. P. Carpenter 1, R. V. F. Janssens1, S. Zhu1, B. Fornal2, R. Broda2, A. Galindo-Uribarri3, N. Hoteling4 , A. Ibanez5,T. L. Khoo1, F. G. Kondev6, T.
Lauritsen1, C. J. Lister1, E. Padilla-Rodal3,7, D. Seweryniak1, J. P. Ureggo-Blanco7, X. Wang1,8
1 Physics Division, Argonne National Laboratory, Argonne, IL 604392 Niewodniczanki Institute of Nuclear Physics, PL-31342, Cracow, Poland
3 Oak Ridge National Laboratory, Oak Ridge, TN 378314 University of Maryland, College Park, MD 20742
5Instituto de Fisica, UNAM6Nuclear Engineering Division, Argonne National Laboratory, Argonne, IL 60439
7University of Tennessee, Knoxville, TN 379968University of Notre Dame, Notre Dame IN 46556
Also - W. B. Walters (Univ. Maryland), A. Hecht (Maryland/ANL)
