Neutron cross section
measurement of MA
Hideo Harada
Nuclear Science and Engineering Directorate,
Japan Atomic Energy Agency
2007 Symposium on Nuclear Data
Nov. 30, 2007, RICOTTI Convention Center2007 Symposium on Nuclear Data

1

Neutron cross section measurement of MA①

Activities in the World②

Activities in Japan for thermal neutrons③

Activities in Japan for keV neutrons④

Possibilities in Japan for MeV neutrons⑤

Summary: Toward improvement in the MA data

2007 Symposium on Nuclear Data2

① Activities in the WorldDANCELANL (USA)Ref.

2007 Symposium on Nuclear Data
研究者数、化学部門との連携、人材育成、大形予算

3

① Activities in the World
IRMM (EU)

Karlsruhe (Germany)

Van de Graff, Electron L. A.:
Fission, Capture, Total, (n,2n)
TOF: Ge, C6D6n-TOF (CERN, EU)
TOF: 4πBaF2, C6D6

keV neutron capture （FP）
Activation @ keV neutrons
TOF: 4πBaF2

ILL (CEA, France)
High flux reactor
activation @ thermal neutrons

Pulse height weighting technique: C6D6 , NaI etc
low neutron sensitivity

TOF method

Total absorption detector: 4πNaI, BGO, BaF2 etc
high efficiency
Gamma-spectroscopic method: Gehigh energy resolution
2007 Symposium on Nuclear Data

4

① Activities in the World
IRMM (EU)Gamma-spectroscopic method: Ge

PR C56, 1266 (1996)
1200h beam time
694g U-238
F.P.=12.85 m
70% Ge2007 Symposium on Nuclear Data

5

Activities in Japan

2002 2003

2004

2005

2006

Fundamental R&D on Neutron Cross Sections forInnovative Reactors Using
Advanced Radiation Measurement Technology

Tohoku: Fission
JAEA: Capture, Decay heat
Kyoto: Capture & Fission

Project Leader: M. Igashira (T.I.T.)

TIT: Capture , γ-spectra

12010080Voltage [ch]6040200-20-40信号波形
ノイズの代表波形-60

JRR-3M
20MW-800500

1000

Time [ch]En=1- 100 keV！
KUR
5MWKURRI

4πGe spectrometer
KURRI electron linac

lead slowing down
spectrometer

YAYOI 2kW2007 Symposium on Nuclear Data

6②Activities in Japan for thermal neutrons

No.1

When there are resonance peaks below 0.5 eV,
can we measure σ０ and resonance integral
correctly ?
10000

Capture cross section (barn)

JE N D L-3.3, T = 300 0 K
E N D F /B -V I, T = 300 0 K

237 N p1000
180.97 b

100 161.73 b

1010.01

Cd cut-off
0.0253 eV0.1

1

10N eutron E nergy (eV )2007 Symposium on Nuclear Data

7②Activities in Japan for thermal neutrons

Reaction

PresentJENDL-3

ENDF/BVII

Mughabghab
Atlas 5th ed.

237Np(n, γ)238Np

σ0 =169±4 b

161.7 b162.2 b175.9±2.9 b

243Am(n, γ)244Am

σ =174.5±5.3 b(150 b)241Am(n, γ)242gAm

σ0g =628±22 b

σ0 639.4 b

References:(150 b)620.84 b

σ0g 533±13 b
σ0 587±12 b

Harada et al. JNST 43 (2006) 1289.
Ohta et al. JNST 43 (2006) 1441.
Nakamura et al. JNST 44 (2007) Dec.
2007 Symposium on Nuclear Data

8②Activities in Japan for thermal neutrons

Ohta et al. JNST 43 (2006) 1441.
2007 Symposium on Nuclear Data

9

③ Activities in Japan for keV neutrons

JAEA, TIT, Kyoto

KURRI Linac+n10m

237Np
93

Neutron flux ! 22m

T1/2= 2.144×106 yr
H2O moderator-1

Relative neutron flux(/MeV)

10e--Ta reaction-310-510-7

10> 1 eV-910-1010-810-61010-410-210010

2Neutron Energy (MeV)2007 Symposium on Nuclear Data

10③ Activities in Japan for keV neutrons: Capture
JAEA, Tokyo Tech., Kyoto
4πGe
Linac shielding wall

spectrometer

Electron beam
BF3-counter neutron monitor
Watermoderator

Evacuated
flight tubes

Lead shadow bar

MAsample

Neutron beamfilters
Neutron producing
target10.0 mLeadConcrete
Np-237

H2BO3
2007 Symposium on Nuclear Data

Am-241
Am-24311

Experiments for Capture
KUR Electron Linear Accelerator Facility

Electron beam：Energy 30 MeV,
Rep. Rate

Ave. Current

31μA

100 Hz, Pulse Width100 ns

4πGe spectrometer
Cluster 2 (14 Ge crystals)
Clover 4 (16 Ge crystals)
BGO anti-coincidence shields

2007 Symposium on Nuclear Data

12

③ Activities in Japan for keV neutrons

Nucl. Instru. Meth. A 562, 767 (2006)

J. Nucl. Sci. Technol. 42, 135 (2005)

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.
2007 Symposium on Nuclear Data
13

Deduced capture cross section of 237Np (5MBq sample)
2007 Symposium on Nuclear Data

14

Comparisons of data for keV neutrons

Needs more statistics for En>100eV

Energy [eV]2007 Symposium on Nuclear Data15

③ Activities in Japan for keV neutrons

FissionTohoku, Kyoto
z 237Np, 241Am, 242mAm, 243Am
z En=1- 100 keVz Kyoto 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
2007 Symposium on Nuclear Data

16

Sample deposit(U-235)

FissionSample deposit(MA)

Ar + CO2Connector
49 mm

Electrode(anode)
Ar + CO2

Chamber(aluminum)
43 mm

120
100
80

NoiseVoltage [ch]60DSP

40Signal

200-20-40

信号波形
ノイズの代表波形-60-800500

1000Time [ch]• Wave form analysis for each slowing down time
• Subtraction of “γ-flash” noise from raw signal (noise + signal)
2007 Symposium on Nuclear Data17

④ Problems in measurement for MeV neutrons
The data is very limited especially for MeV neutrons.
237

Np capture

Cross Section (b)101present (=CCONE)JENDL-3.3
ENDF/B-VII.0

Nakagawa 2007

100
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)

10-1

10-2103

104
105
106
Neutron Energy (eV)2007 Symposium on Nuclear Data

107

18

④

Possibilities in Japan for MeV neutrons

Activation by fast neutrons at Yayoi

2007 Symposium on Nuclear Data

19

④Possibilities in Japan for MeV neutrons

放射線標準施設

http://www3.tokai-sc.jaea.go.jp/rphpwww/senryo/index2.htm

TOF by fast neutrons at JAEA Tokai
2007 Symposium on Nuclear Data

20

⑤ Toward improvement in the MA data
LANL, IRMM,n-TOF

CEA ILL
IntegralAbroadYayoi

KUR

KURRI linac

JRR3

J-PARC

T.I.T.

Japan

differential

thermaleV

keV

放射線標準施設

JAEA

MeV

Neutron Energy

Several facilities covering a wide energy range are or will be soonavailable 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 areimportant. The comparisons of independent measurements will help to
notice the unexpected systematic uncertainties.
2007 Symposium on Nuclear Data21