Consistent nuclear-model parameters, accurate model assumptions

Transcription

PN2_IDEI_149/2007 [ http://proiecte.nipne.ro/pn2/ ]
Workshop on Activation Data – EAF 2009
25-27 March 2009, Prague
Consistent nuclear-model parameters, accurate model
assumptions, and uncertainties of calculated α-particle
activation at low energies
Vlad Avrigeanu, Marilena Avrigeanu
“Horia Hulubei” National Institute for Physics & Nuclear Engineering,
Bucharest, Romania
http://tandem.nipne.ro/~vavrig/Projects/PN2P3_149/
Content/Object:
Analysis of α-particle induced reactions on
92,94Mo
Vlad Avrigeanu
and 112,117Sn @ low energies (< 15 MeV)
EAF-2009, Prague, 25-27 March 2009
1
α-particle induced reactions @ E<50 MeV
Vlad Avrigeanu
2
Next, soon…
Vlad Avrigeanu
3
…even more:
10
22
10
21
10
20
10
19
10
26
10
25
10
24
10
23
10
26
10
25
10
24
10
23
McFadden
Huizenga
Avrigeanu
S factor (keV b)
117
0
10
117
121
117
121
Sn(α,γ) TeIZO (11/2-) 154 d
-1
10
Sn(α,γ) TeGS (1/2+) 19.16 d
117
10
121
117
121
Sn(α,γ) TeIZO (11/2-) 154d
Sn(α,γ) TeGS (1/2+) 19.16 d
9
-3
10
Cross section (b)
117
120
Sn(α,p) SbIZO (8-) 5.76 d
-2
120
Sn(α,p) SbIZO (8-) 5.76 d
10
11
12
13
14
15
16
Eα C.M. (MeV)
-4
10
-5
10
McFadden
117
121
Sn(α,γ) Te
117
121
Sn(α,γ) TeGS
-6
10
-7
10
117
121
117
120
Sn(α,γ) TeIZO
-8
Nonsmoker
117
121
Sn(α,γ) Te
117
120
Sn(α,n) Te
117
120
Sn(α,p) Sb
10
-9
10
Sn(α,n) Te
120
Sn(α,p) Sb
117
120
Sn(α,p) SbGS
117
117
120
Sn(α,p) SbIZO
-10
10
9
10
11
12
13
14
15
16
17
18
Eα (MeV)
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Our 2003-statements, from the beginning:
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Nuclear Model Calculations
OPTICAL MODEL : prime tool for all cross section calculations
Phenomenological OMP (global parameter sets): still extensively used
Microscopic OPs: reduced uncertainties (e.g., OM ambiguities)
Pure elastic scattering OP analysis
SCAT2 [O. Bersillon]
- phenomenological OP
+ semi-microscopic (DF) OP
(local version)
Coupled Reaction Channel (CRC)
FRESCO-2003 [I.J. Thompson]
Phys.
Phys.Rev.
Rev. C62
C62(2000)
(2000)017001
017001
Nucl.
Nucl.Phys.
Phys.A693
A693(2001)
(2001)616
616
Eur.
Eur.Phys.
Phys.J.J. A12
A12(2001)
(2001)399
399
Int.
Int.J.J.ofofMod.
Mod.Phys.
Phys.E,E,11
11(2002)
(2002)249
249
Nucl.
Nucl.Phys.
Phys.A723
A723(2003)
(2003)104
104
Nucl.
Nucl.Phys.
Phys.AA759
759(2005)
(2005)327
327
Nucl.
Nucl.Phys.
Phys.AA764
764(2006)
(2006)246
246
Composite system equilibration
- Geometry Dependent Hybrid (GDH) preequilibrium-emission model
- Hauser-Feshbach (HF) statistical model

STAPRE-H95 [V. Avrigeanu, M. Avrigeanu]
(updated)
Vlad Avrigeanu
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Nuclear data (ND) consistent model calculations
[ E.D. Arthur – P.G. Young, LANL, ’80 ]
YES
[ IAEA/NDS RCs (12), Bucharest, 1982-2005 ]
i.
unitary use of common model parameters for different
mechanisms
ii.
use of consistent sets of input parameters - determined by
analyses of various independent experimental data
iii.
unitary account of whole body of related experimental data
for isotope chains and neighboring elements
[ activation & particle-emission spectra ]
[ enlarged incident-energy range ]
NO
Vlad Avrigeanu
Vlad Avrigeanu
re-normalization or free parameters (widely-used within ND libraries)
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7
Our results:
GQR ?
G. Duhamel et al.,
Phys.Rev.C 38, 2509(1988):
92
Mo: E0=14.1 MeV, Γ=4.5 MeV
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Additional check of neutron/proton OMPs
EC Report EUR 23235 EN, 2008, p. 143
www.irmm.jrc.be/html/publications/
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Former check of γ-ray strength functions
EC Report EUR 23235 EN, 2008, p. 143
www.irmm.jrc.be/html/publications/
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a-smooth curve method (A~120)
[ C.H. Johnson, Phys. Rev. C 16, 2238 (1977) ]
Back-Shifted Fermi Gas (BSFG) model
I/Irigid= 0.5 - 0.75(Bn) - 1 (15 MeV)
even-even
even-odd
odd-even
odd-odd
-1
a (MeV )
20
15
A/8
A/9
A/10
10
80
100
120
140
160
(a)
180
200
En (MeV)
V. Avrigeanu et al., J. Nucl. Sci. Tech. Suppl. 2, 746 (2002);
http://tandem.nipne.ro/~vavrig/publications/2002/Tables/
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More calculations/codes
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HF parameters….?
E(c.m.) / B
0.71
0.01
117
0.84
0.90
0.97
121
Sn(α,γ) Te
0.78
0.84
117
120
0.90
Sn(α,p) Sb
0.97
m
Γγ=316meV
Cata+(2008): g+m
Cata+(2008): g
Cata+(2008): m
Γγ=158meV
OMP: KD(2002)
120Sb: Δ-200 keV
+ 120Te: Δ+200 keV
+ 120Te: a=16 / MeV
σ (b)
1E-3
0.78
1E-4
Γγ=316meV
Γγ=158meV
OMP: KD(2002)
120Sb: Δ-200 keV
+ 120Te: Δ+200 keV
+ 120Te: a=16 / MeV
1E-5
11
12
13
14
15
12
13
14
15
E(c.m.) (MeV)
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Nuclear level density - data/parameters/systematics
100
120,122,124
N (E*)
NUDAT (2003): Sb
116
NUDAT (): Sb
118
NUDAT (): Sb
120
NUDAT (): Sb
122
NUDAT (): Sb
124
NUDAT (): Sb
126
NUDAT (): Sb
Sb
51
69,71,73
100
120,122,124,126
116
Te
118
Te
120
Te: Bn= 10.296, I0=1/2
Te
52
122
Te: Bn= 9.825, I0=1/2
124
Te: Bn= 9.425, I0=1/2, D0=.017(3)
126
Te: Bn= 9.113, I0=1/2,
68,70,72,74
.038(5)
128
120: Bn= 7.021, I0=5/2
10
122: Bn= 6.807, I0=5/2: D0=.013(2)
124: Bn= 6.467, I0=7/2:
N (E*)
114
Te
130
Te
10
.024(3)
120
Sb: 13.95/.5-1/-1.40: D0=.0129
120
120
Te: 14.40/.5-1/0.80: D0=.00748
120
120
Te: 13.25/.5-1/0.80: D0=.0205
Sb: 13.50/.5-1/-1.40: D0=.0187
Sb: 13.75/.5-1/-1.35: D0=.0160
120
Te: 14.00/.5-1/0.87: D0=.0114
122
Sb: 14.00/.5-1/-1.47: D0=.0150
122
124
Sb: 13.50/.5-1/-1.52: D0=.0267
Te: 14.60/.5-1/0.80: D0=.0173
126
Sb: 13.50/.5-1/-1.60: D0=.0336
1
0.0
0.5
E* (MeV)
Vlad Avrigeanu
1.0
Te: 14.20/.5-1/0.94: D0=.0175
124
126
Te: 14.20/.5-1/0.85: D0=.037
1
0.5
1.0
1.5
2.0
2.5
3.0
3.5
4.0
E* (MeV)
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Possible motivation: DSD radiative capture
•K.Raghunathan et al., PRC 22,2409(1980):
Direct radiative capture: Eα~10-11 MeV
•J.A. Behr et al, PRC 53,1759(1996):
Nonstatistical γ emission: Eα~11-27 MeV
D.G. Gardner, UCRL-87438 (1982) :
Fast neutron DSD
- Eg. (8)
- fit of cross sections
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Final results
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Conclusions
•Achievements
¾ROP-2008: accurate description of (α,α) @ E<50 MeV
¾(α,n) data for 92,94Mo, 112Sn nuclei: ROP-2008 support
•Open Questions
¾New (α,γ) data for 117Sn nucleus
¾Direct radiative capture ?
•Next (final?) step for α-OMP:
¾α-particle emission
¾Calculated (n,α) reaction cross-section enhanced accuracy
Vlad Avrigeanu
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Vlad Avrigeanu
Thank you !
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Consistent nuclear-model parameters, accurate model assumptions

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