AGATA@GSI LoI
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Transcript of AGATA@GSI LoI
AGATA@GSI LoI
Relativistic Coulomb M1 excitation of neutron-rich
85BrN. PietrallaG. Rainovski
J. Gerl
D. Jenkins
Evolution of the proton SPEs towards 78NiApproaching 78Ni from left - N=40 to N=50
Z=28
50
K.T. Flanagan et al., PRL 103, 142501 (2009) T. Otsuka et al., PRL 104, 012501 (2010)
89Y, NNDC; 87Rb, L. Käubler et al., PRC 65, 054315; 85Br NNDC; 83As, NNDC and E, Sahin et al., AIP Conf. Proc. 1072, 298 (2008), 1012, 139 (2008); 81Ga, D. Verney at al. PRC 76, 054312 (2007)
39
?
(391)
(0)
p 1/2
p 1/2
p 3/2p 3/2
p 3/2
f5/2 f5/2 f5/2
p 1/2
p 3/2
f5/2 - 345
1191
0 0
306
669
0
351
p 1/2
p 3/2
f5/2
845
- 403
0p 1/2
p 3/2
f5/2
0
- 1507
- 1745
ESPE
(kEV
)
39 37 35 33 31 29
Approaching 78Ni from above - Z=40 to Z=28
1/2-
3/2-5/2-
15071745
0
15071745
89Y
1/2-
3/2-
5/2-
845
403
0403
845
87Rb
(1/2)-
(5/2,3/2)- -
(3/2,5/2)- -
0
306
669
306
363
83As
(5/2)-
(3/2)-
(3/2)-
0
351
803
351
452
81Ga
1/2-
3/2-
5/2- 345
1191
0345
1191
85Br 79Cu
?(1/2)-
(3/2)-
(5/2)-
(391)
(0)
?
1) E(p3/2) – E(f5/2) constant
2) E(p1/2) – evolves ???28
50
p1/2 ???
What is the unique experimental signature of p1/2?
1/2-
3/2-5/2-
15071745
0
15071745
89Y
1/2-
3/2-
5/2-
845
403
0403
845
87Rb
1/2-
3/2-
5/2- 345
1191
0345
1191
85Br
Spin-flip M1 transitions: direct observation of spin-orbit splitting
Relativistic Coulomb excitation reactions
1p (l=1)
j < =
l-1/
21p1/2
j> = l+1/2
1p3/2
B(M1;j>j<) 1 N2
Unique signature!!!
0.68(10) N2
0.47(5) N2
???
c(E2) (1/)2
c(M1) – independent
at high v/c large M1 matrix elements can significantly contribute to the total CE yieldRelativistic beam energies
50-80 %
Huge Doppler spread in the
observed -ray spectrum
need of capability to perform precise Doppler
correction and reduce the Doppler broadening
AGATA
Unique at GSI
Test case – 85Br
1/2-
3/2-
5/2- 345
1191
0345
1191
• primary beam – 86Kr with intensity of about 109 pps • primary target – 2 g/cm2 9Be
• secondary beam – 85Br, produced in fragmentation - 10 mb • secondary beam energies – 200 MeV/u and 450 MeV/u• beam intensity at S4 – 105 pps (10% FRS efficiency)• yield estimates - 10% efficiency of AGATA+PRESPEC set-up
Assume the same strengths as in 87Kr:B(E2;5/2-3/2-)= 40 e2fm4 B(M1;5/2-3/2-)=10-2N
2
B(M1;1/2-3/2-)=0.58 N2
Ebeam(MeV/u) v/c Elevel(keV) J CE(mb) Yield (/h)
200 0.57345 5/2- 6.94 234
1191 1/2- 0.64 22
450 0.74345 5/2- 4.21 142
1191 1/2- 0.78 26
• Disentangle E2 and population from GDR: DSAM, two beam energies and multiplicity-total energy gates HECTOR
Beam time – 100 h85Br
SummaryRelativistic Coulomb M1 excitation of neutron-rich 85Br
• physics goal - to fix the relative spacing between the p1/2 and p3/2 orbitals in the neutron rich nucleus 85Br• methodological goal - to show that the method of relativistic Coulomb excitation is a reliable experimental tool for quantitative study of M1 excitation strengths in exotic nuclei
Requires RIB at relativistic energies –
unique at GSIRequires capability for high resolution -ray spectrometry at
v/c 50-80% - needs AGATA