Surrogate Reactions using. STARS+LIBERACE. AFCI Workshop. August 10-11,
2006. Bethesda, MD. L.A. Bernstein. LLNL. This work was performed under the ...
Surrogate Reactions using STARS+LIBERACE L.A. Bernstein LLNL
AFCI Workshop August 10-11, 2006 Bethesda, MD UCRL pending This work was performed under the auspices of the U.S. Department of Energy by the University of California, Lawrence Livermore National Laboratory under Contract No. W-7405-Eng-48.
Silicon Telescope Array for Reaction Studies (STARS) Experimental Schematic 140 µm ΔE detector
Front Energy
1000 µm E detectors
STARS
LiBerACE
Al δ-electron & fission fragment shield
γ
140 µm fission detector
55 MeV α’s
3He
α
p,d,t
Fission Fragments
γ 238U
Back Energy
target “clover” Ge γ-ray detectors
-1-
STARS+LiBerACE: (Livermore-Berkeley Array for Collaborative Experiments) Target Chamber+6 “Clover” Ge
STARS
LiBerACE
Interior w/S2 Si detectors
Started: 4/04 at Yale, moved to LBNL 9/04 3 papers published, 1 submitted, 1 in progress Data Taken: 4/04, 12/04, 3/05 and 2/06 -2-
Year 1 of the LiBerACE Surrogate Reactions Program: 237U(n,destruction) 4
2.5
(n,f)+(n,2n)
3
(n,f)
2 1.5
2 1
1
0.5
α
0 5
7.5
10 12.5 15 17.5 Neutron Energy (MeV)
20
n 237U
1.8 1.6 1.4 1.2 1 0.8 0.6 0.4 0.2 0
238U*
0 0
α
2.5
5
7.5
10
12.5
15
17.5
20
Neutron Energy (MeV)
238U 237U(n,g) from (a,ag)/(a
(n,2n)
1.2
1
(n,gamma) Sn(238U) (n,gamma) from abs. pro
(n,γ)
0.8
`
0.6
0.4
0.2
5 STARS STARS
LiBerACE LiBerACE
7.5
10 12.5 15 17.5 Neutron Energy (MeV)
20
0 6
6.1
6.2
6.3
6.4
6.5
6.6
6.7
6.8
Excitation Energy (Me
-3-
6.9
7
7.1
7.2
7.3
7.4
Also in the first year - Ratio method benchmark 234U(α,α’f)/236U(α,α’f) vs. 233U(n,f)/235U(n,f) 2 234U(a,a'f)/236U(a,a'f) Ratio from STARS 234U(α,α’f)/234U(α,α’f) from STARS
233U(n,f)/235U(n,f) 233U(n,f)/235U(n,f) from ENDF-B7 from ENDF-B7
1.5
1
2.5
≈20% discrepancy near 0-120 keV
2 1.5
Shelly Lesher From Richmond
1
0.5
0.5 0 7
7.12 7.24 7.36 7.48 7.6 7.72 7.84 7.96 Excitation Energy (MeV)
0 STARS
7
12
17
Excitation Energy (MeV) LiBerACE
-4-
22
“Basic Science” surrogate program • Astrophysics: (n,γ) cross sections on s-process branch point nuclei – –
101,103Ru
(J.A. Church, LLNL) 153,155Gd (D.L. Bleuel, LBNL)
• Understanding how a hot nucleus equilibrates. – Spin sensitivity for absolute & ratio surrogate methods. •
238,235U(3He,3He’)
and (3He,α) (B. Lyles, UC-Berkeley)
– Using (d,p) as a surrogate for (n,γ) •
143,145Nd(d,p)
(Robert Hatarik - Rutgers)
– Dependence on entrance channel • TBD (Richmond/Yale+) STARS
LiBerACE
Benchmarking the technique is a major part of our effort -5-
What we will do: (n,f), (n,γ) for En>187 keV for short-lived ( t1/2100) nuclei Target Surrogate Reactions
Ratio Reactions
Reactor Type*
238Pu
239Pu(α,α’)
235U(α,α’)
LFR,SFR
239Pu
239Pu(d,p), 240Pu(α,α’)
235U(d,p), 236U(α,α’)
GFR,LFR,SFR,EFR
240Pu
240Pu(d,p), 242Pu(3He,α)
236U(d,p), 236,238U(3He,α)
GFR,LFR,SFR,EFR
241Pu
242Pu(α,α’)
236U(α,α’)
GFR,LFR,SFR,EFR
241Am
243Am(3He,α), 240Pu(3He,d)
235U(3He,α),
242mAm
242Pu(3He,t), 243Am(α,α’)
238U(3He,t), 235U(α,α’)
LFR,SFR
243Am
243Am(d,p), 242Pu(3He,d)
239Pu(d,p),
SFR
242Cm
243Am(3He,t)
238U(3He,t)
EFR
243Cm
245Cm(3He,α), 243Am(3He,t)
235U(3He,α), 238U(3He,t)
GFR,EFR
244Cm
245Cm(α,α’), 243Am(3He,d)
235U(α,α’),
GFR,LFR,SFR,EFR
245Cm
247Cm(3He,α), 245Cm(d,p)
235U(3He,α), 235U(d,p)
LiBerACE
none yet
none yet
*from
STARS
-6-
GFR,LFR,SFR
none yet
LFR,SFR,EFR
Aliberti et al.,
Collaborators LLNL LBNL University of Richmond Yale University Rutgers University University of California-Berkeley (Nuclear Eng.)
This program is integrating national lab scientists with faculty, post-docs, graduate and undergraduate students STARS
LiBerACE
-7-
