NUSTAR Calorimeter WG activity report Nustar Management Board, September 14-15 2006.
NUSTAR 05 - 1 Neutron Knockout from Intermediate Energy Beams of 26,28 Ne J.R. Terry 1,2, D. Bazin...
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NUSTAR 05 - 1 Neutron Knockout from Intermediate Energy Beams of 26,28 Ne J.R. Terry 1,2 , D. Bazin 1 , B.A.Brown 1,2 , C.M. Campbell 1,2 , J.A. Church 1,2 , J.M. Cook 1,2 , A.D. Davies 1,2 , D.C. Dinca 1,2 , J. Enders 1 , A. Gade 1 , T.Glasmacher 1,2 , P.G. Hansen 1,2 , J.L. Lecouey 1 ,W.F. Mueller 1 ,H. Olliver 1,2 , B.M. Sherrill 1,2 , J.A. Tostevin 3 , K. Yoneda 1 1 National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA 2 Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA 3 School of Electronics and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
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Transcript of NUSTAR 05 - 1 Neutron Knockout from Intermediate Energy Beams of 26,28 Ne J.R. Terry 1,2, D. Bazin...
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Neutron Knockout from Intermediate Energy Beams of 26,28Ne
J.R. Terry1,2, D. Bazin1, B.A.Brown1,2, C.M. Campbell1,2, J.A. Church1,2, J.M. Cook1,2, A.D. Davies1,2, D.C. Dinca1,2, J. Enders1, A. Gade1, T.Glasmacher1,2, P.G. Hansen1,2, J.L. Lecouey1,W.F. Mueller1,H.
Olliver1,2, B.M. Sherrill1,2, J.A. Tostevin3, K. Yoneda1
1National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA
2Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
3School of Electronics and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
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Neutron Knockout from Intermediate Energy Beams of 26,28Ne
• Direct quantitative observation of negative parity intruder configuration in 28Ne.
• First observation of the level structure of 27Ne.
8 16
20
28
8
20
ZN
28Ne
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KNOCKOUT REACTION IN INVERSE KINEMATICS AT ENERGIES OF 60-100
MeV/nucleon
A A-1E
kA-1
Observables:
•Cross section of nucleon-removal reaction
•Population fraction to individual excited states by detection of coincident transition gamma rays
•Longitudinal momentum distribution of reaction residue
Three-body reaction theory based on Sudden and Eikonal approximations:
•Core-target and nucleon-target S-matrices calculated from Glauber theory
• Core-nucleon interaction modeled by a two-body Wood-Saxon potential
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9Be(26Ne,25Ne)X
J.R. Terry, J.L. Lecouey, Nucl. Phys. A734 (2004) 469-472
Elevel Jπ l b [%] σsp [mb] σobs [mb] C2Sobs C2Sth Eth
0 1/2+ 0 48(7) 41.7 46(7) 1.1(2) 1.347 0
1703 5/2+ 2 22(6) 21.5 21(6) 1.0(3) 2.346 1.779
3316 5/2+ 2 21(3) 19.3 20(3) 1.0(2) 1.837 2.971
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S800 SpectrographSegmented Germanium
Detector Array SeGA
Focal Plane
Yellow arrow indicates beam path
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9Be(28Ne,27Ne)X
Inclusive Cross Section: 66.7(33) mb
First observation of excited states in 27Ne: three gamma transitions: 119(3), 765(5), 885(5) keV.
37.7(20) % of events have no observed coincident transition gamma rays
Gamma-gamma analysis
885(5) 48.1(21)
765(5) 14.2(16)
0.83
0(17
) %0.
170(
17) %
E [keV] Branch [%]
119(
3) k
eV
0
119 keV
9Be(28Ne,27Ne)X
765 keV gated
885 keV gated
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l=0
l=3
l=2
l=3
l=0
l=2
l=3
765 keV 885 keV
Events with no coincident transition gamma
Momentum Distributions
765 and 885 keV coincident events have momentum distributions characteristic of an l=2 neutron removal
Momentum distribution for events with no coincident transition gamma ray is not consistent with any single-l valued distribution.
Combination of l=0 and l=3, 12% and 88%, respectively, fits the data.
Longitudinal Momentum Distribution [GeV/c]
Longitudinal Momentum Distribution [GeV/c]
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ResultsJπ l σpartial [mb] σsp [mb] C2Sobs
(3/2,5/2)+ 2 32.1(21) 23.6 1.36(9)
(3/2,5/2)+ 2 9.5(11) 23.6 0.40(5)
7/2- 3 22.1(21) 23(1) 0.96(10)
(1/2+) (0) 3.00(64) 44.4 0.068(14)
83.0
(17)
%
17.0
(17)
%
0.000
0.765(5)
0.885(5)
X
E [MeV]
27Ne
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Comparison to USD
1
0
2
3/2+ 2 1.58
1/2+ 0 1.35
5/2+ 2 0.04
3/2+ 2 0.105/2+ 2 1.08
Jπ l C2S Jπ l C2S
(1/2+) (0) 0.068(14)
7/2- 3 0.96(10)
(3,5)/2+ 2 0.40(5)(3,5)/2+ 2 1.36(9)
Sn=1.43 MeV
USD Exp
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NILSSON DIAGRAM FOR N,Z < 20 ½,
½0 ½)()1()1( K
I IaIIAEE
a = - 3.5
a = - 0.5
1
0
2
[200]1/2+
1/2+
[202]3/2+
3/2+
[330]1/2-
3/2-
3/2+
5/2+
7/2-
1/2-
5/2-
5/2+
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Comparison of the (28Ne,27Ne) f7/2 Spectroscopic Factor with fp-shell occupancies from the Monte
Carlo Shell Modela)
a) Y. Utsuno, T. Otsuka, T. Mizusaki and M. Honma, Phys. Rev. C 60, 054315 (1999)
16 18 20 22 24N eutron N um ber
0
0.5
1
1.5
2
2.5<
Nfp
> -
Nno
rma
l Z = 10 (N e)
.
Exp. (N e)
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Outlook
• Complete analysis of 28NeAngular distributions of de-excitation gamma rays
• Analyze single-neutron removal from 30,32Mg
16 18 20 22 24N eutron N um ber
0
0.5
1
1.5
2
2.5
<N
fp>
- N
norm
al Z = 10 (N e)
.
Z = 12 (M g)
Exp. (N e)
30Mg
32Mg
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Neutron Knockout from Intermediate Energy Beams of 26,28Ne
J.R. Terry1,2, D. Bazin1, B.A.Brown1,2, C.M. Campbell1,2, J.A. Church1,2, J.M. Cook1,2, A.D. Davies1,2, D.C. Dinca1,2, J. Enders1, A. Gade1, T.Glasmacher1,2, P.G. Hansen1,2, J.L. Lecouey1,W.F. Mueller1,H.
Olliver1,2, B.M. Sherrill1,2, J.A. Tostevin3, K. Yoneda1
1National Superconducting Cyclotron Laboratory, Michigan State University, East Lansing, MI 48824, USA
2Department of Physics and Astronomy, Michigan State University, East Lansing, MI 48824, USA
3School of Electronics and Physical Sciences, University of Surrey, Guildford GU2 7XH, UK
