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2007 Symposium on Nuclear Data 1
Neutron cross section measurement of MA
Hideo HaradaNuclear Science and Engineering Directorate,
Japan Atomic Energy Agency
2007 Symposium on Nuclear DataNov. 30, 2007, RICOTTI Convention Center
2007 Symposium on Nuclear Data 2
① Activities in the World
② Activities in Japan for thermal neutrons
③ Activities in Japan for keV neutrons
④ Possibilities in Japan for MeV neutrons
⑤ Summary: Toward improvement in the MA data
Neutron cross section measurement of MA
2007 Symposium on Nuclear Data 3
① Activities in the World
LANL (USA)DANCE
Ref.
研究者数、化学部門との連携、人材育成、大形予算
2007 Symposium on Nuclear Data 4
① Activities in the World
n-TOF (CERN, EU) ILL (CEA, France)
Karlsruhe (Germany)IRMM (EU)
High flux reactor activation @ thermal neutrons
keV neutron capture (FP)Activation @ keV neutrons TOF: 4πBaF2
Van de Graff, Electron L. A.: Fission, Capture, Total, (n,2n)TOF: Ge, C6D6
TOF: 4πBaF2, C6D6
TOF method
Pulse height weighting technique: C6D6 , NaI etc low neutron sensitivity
Total absorption detector: 4πNaI, BGO, BaF2 etc high efficiency
Gamma-spectroscopic method: Ge high energy resolution
2007 Symposium on Nuclear Data 5
① Activities in the WorldIRMM (EU) Gamma-spectroscopic method: Ge
PR C56, 1266 (1996)
1200h beam time
694g U-238
F.P.=12.85 m
70% Ge
2007 Symposium on Nuclear Data 6
2003 2004 2005 20062002Fundamental R&D on Neutron Cross Sections for
Innovative Reactors Using Advanced Radiation Measurement Technology
Project Leader: M. Igashira (T.I.T.)
Activities in Japan
0 500 1000-80
-60
-40
-20
0
20
40
60
80
100
120
信号波形 ノイズの代表波形
Voltag
e [
ch]
Time [ch]
En=1- 100 keV! 4πGe spectrometer
KURRI
lead slowing down spectrometer
KURKUR5MW5MW
JRRJRR--3M3M20MW20MW
KURRI electron linac
Tohoku: Fission
JAEA: Capture, Decay heat
Kyoto: Capture & Fission
TIT: Capture , γ-spectra
YAYOI 2kWYAYOI 2kW
2007 Symposium on Nuclear Data 7
② Activities in Japan for thermal neutrons
No.1
Neutron Energy (eV)0.01 0.1 1 10
Cap
ture
cro
ss s
ectio
n (b
arn)
1
10
100
1000
10000JENDL-3.3, T = 3000KENDF/B-VI, T = 3000K
180.97 b
161.73 b
0.0253 eV
237Np
Cd cut-off
When there are resonance peaks below 0.5 eV, can we measure σ0 and resonance integral correctly ?
2007 Symposium on Nuclear Data 8
σ0 639.4 bσ0g =628±22 b241Am(n, γ)242gAm
(150 b)σ =174.5±5.3 b243Am(n, γ)244Am
161.7 bσ0 =169±4 b237Np(n, γ)238Np
JENDL-3PresentReaction
References: Harada et al. JNST 43 (2006) 1289.Ohta et al. JNST 43 (2006) 1441.Nakamura et al. JNST 44 (2007) Dec.
σ0g 533±13 bσ0 587±12 b
620.84 b
(150 b)
175.9±2.9 b162.2 b
MughabghabAtlas 5th ed.
ENDF/B-VII
② Activities in Japan for thermal neutrons
2007 Symposium on Nuclear Data 9
Ohta et al. JNST 43 (2006) 1441.
② Activities in Japan for thermal neutrons
2007 Symposium on Nuclear Data 10
③ Activities in Japan for keV neutrons
T1/2= 2.144×106 yr
+ n
237Np93
10-9
10-7
10-5
10-3
10-1
10-10 10-8 10-6 10-4 10-2 100 102
Rel
ativ
e ne
utro
n flu
x(/M
eV)
Neutron Energy (MeV)
> 1 eV
e--Ta reactionH2O moderator
KURRI Linac
Neutron flux ! 22m10m
JAEA, TIT, Kyoto
2007 Symposium on Nuclear Data 11
Electron beam
Neutron producing target
Water moderator
Lead shadow bar
BF3-counter neutron monitor
Neutron beam filters
Linac shielding wall
Evacuated flight tubes
Lead Concrete
H2BO3
10.0 m
MA sample
44ππGe Ge spectrometerspectrometer
Np-237
Am-241
Am-243
③Activities in Japan for keV neutrons: CaptureJAEA, Tokyo Tech., Kyoto
2007 Symposium on Nuclear Data 12
Electron beam:Energy 30 MeV, Ave. Current 31μA
Rep. Rate 100 Hz, Pulse Width 100 ns
44ππGe spectrometerGe spectrometer
Cluster 2 (14 Ge crystals)
Clover 4 (16 Ge crystals)
BGO anti-coincidence shields
Experiments for CaptureExperiments for Capture
KUR Electron Linear Accelerator Facility
2007 Symposium on Nuclear Data 13
J. Nucl. Sci. Technol. 42, 135 (2005)
Nucl. Instru. Meth. A 562, 767 (2006)
水本等、原子力学会2007年秋の大会
The data were successfully obtained, but needs more statistics for high energy region.
③ Activities in Japan for keV neutrons
2007 Symposium on Nuclear Data 14
Deduced capture cross section of 237Np (5MBq sample)
2007 Symposium on Nuclear Data 15
Needs more statistics for En>100eV
Comparisons of data for keV neutrons
Energy [eV]
2007 Symposium on Nuclear Data 16
237Np, 241Am, 242mAm, 243AmEn=1- 100 keVKyoto University Lead Slowing Down Spectrometer (KULS)*driven by a 46 MeV electron linear accelerator*Kobayashi et al; measurements for minor actinide, En< 20 keV
In the present study• Back-to-back fission chamber (BTB, Ratio measurement)
235U 99.9 %, as a standard• For extension of energy range to high energy side,
- Digital signal processing (DSP) technique to eliminate “γ-flash”
- Heavy electrical shielding of BTB, cable, PA• Quantitative assay of samples: low geometry α-counting
Tohoku, KyotoFission③ Activities in Japan for keV neutrons
2007 Symposium on Nuclear Data 17
• Wave form analysis for each slowing down time• Subtraction of “γ-flash” noise from raw signal (noise + signal)
DSPDSP
0 500 1000-80
-60
-40
-20
0
20
40
60
80
100
120
信号波形 ノイズの代表波形
Voltag
e [
ch]
Time [ch]
Noise
Signal
Fission
Ar + CO2
Ar + CO2
Connector
Electrode(anode)
Sample deposit(U-235)
Sample deposit(MA)
Chamber(aluminum)
43 mm
49 mm
Ar + CO2
Ar + CO2
Connector
Electrode(anode)
Sample deposit(U-235)
Sample deposit(MA)
Chamber(aluminum)
Ar + CO2
Ar + CO2
Connector
Electrode(anode)
Sample deposit(U-235)
Sample deposit(MA)
Chamber(aluminum)
43 mm
49 mm
2007 Symposium on Nuclear Data 18
The data is very limited especially for MeV neutrons.
④ Problems in measurement for MeV neutrons
103 104 105 106 10710-2
10-1
100
101
Neutron Energy (eV)
Cro
ss S
ectio
n (b
)
D.C.Stupegia+ ('67) M.Lindner+ ('76) L.W.Weston+ ('81) Ju.N.Trofimov+ ('83) N.N.Buleeva+ ('88) N.N.Buleeva+ ('88) N.N.Buleeva+ ('88) Katsuhei Kobayashi+ ('02) Katsuhei Kobayashi+ ('02) E.I.Esch+ ('05)
237Np capture
present (=CCONE) JENDL-3.3 ENDF/B-VII.0
Nakagawa 2007
2007 Symposium on Nuclear Data 19
④ Possibilities in Japan for MeV neutrons
Activation by fast neutrons at Yayoi
2007 Symposium on Nuclear Data 20
④ Possibilities in Japan for MeV neutrons
TOF by fast neutrons at JAEA Tokai
http://www3.tokai-sc.jaea.go.jp/rphpwww/senryo/index2.htm
放射線標準施設
2007 Symposium on Nuclear Data 21
⑤ Toward improvement in the MA data
Neutron Energythermal eV keV MeV
JRR3 J-PARC放射線
標準施設
KURYayoi
KURRI linac
LANL, IRMM, n-TOF
CEA ILL
differential
Integral
JAEA
Japan
Abroad
T.I.T.
Several facilities covering a wide energy range are or will be soon available for the measurements of MA cross section in Japan. High flux field will contribute to deduce statistical uncertainties. Efforts to deduce the experimental uncertainties including systematic uncertainties are important. The comparisons of independent measurements will help to notice the unexpected systematic uncertainties.
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