Neutron cross section measurement of MA Hideo Harada Nuclear - PowerPoint PPT Presentation

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 Center 2007 Symposium on Nuclear Data 1

Neutron cross section measurement of MA 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 2007 Symposium on Nuclear Data 2

① Activities in the World DANCE LANL (USA) Ref. 2007 Symposium on Nuclear Data 3 研究者数、化学部門との連携、人材育成、大形予算

① Activities in the World IRMM (EU) Karlsruhe (Germany) Van de Graff, Electron L. A.: keV neutron capture （ FP ） Fission, Capture, Total, (n,2n) Activation @ keV neutrons TOF: Ge, C 6 D 6 TOF: 4 π BaF 2 n-TOF (CERN, EU) ILL (CEA, France) High flux reactor TOF: 4 π BaF 2 , C 6 D 6 activation @ thermal neutrons Pulse height weighting technique: C 6 D 6 , NaI etc low neutron sensitivity Total absorption detector: 4 π NaI, BGO, BaF 2 etc TOF method high efficiency Gamma-spectroscopic method: Ge high 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% Ge 2007 Symposium on Nuclear Data 5

Activities in Japan 2002 2003 2004 2005 2006 Fundamental R&D on Neutron Cross Sections for Tohoku: Fission Innovative Reactors Using JAEA: Capture, Decay heat Advanced Radiation Measurement Technology Kyoto: Capture & Fission Project Leader: M. Igashira (T.I.T.) TIT: Capture , γ -spectra 120 100 80 60 Voltage [ch] 40 20 0 -20 -40 信号波形 -60 ノイズの代表波形 JRR- -3M 3M JRR -80 0 500 1000 Time [ch] 20MW 20MW En=1- 100 keV ！ 4 π Ge spectrometer KUR KUR KURRI electron linac KURRI 5MW 5MW lead slowing down spectrometer YAYOI 2kW YAYOI 2kW 2007 Symposium on Nuclear Data 6

② Activities in Japan for thermal neutrons When there are resonance peaks below 0.5 eV, No.1 can we measure σ ０ and resonance integral correctly ? 10000 JENDL-3.3, T = 3000K 237Np ENDF/B-VI, T = 3000K Capture cross section (barn) 1000 180.97 b 161.73 b 100 10 Cd cut-off 1 0.0253 eV 0.01 0.1 1 10 Neutron Energy (eV) 2007 Symposium on Nuclear Data 7

② Activities in Japan for thermal neutrons ENDF/B- Mughabghab Reaction Present JENDL-3 Atlas 5 th ed. VII 237 Np(n, γ ) 238 Np σ 0 =169 ± 4 b 161.7 b 162.2 b 175.9±2.9 b 243 Am(n, γ ) 244 Am σ =174.5 ± 5.3 b (150 b) (150 b) σ 0g 0g 533 ± 13 b 241 Am(n, γ ) 242g Am σ 0g σ 0 639.4 b 0g =628 ± 22 b 620.84 b σ 0 587±12 b References: 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

② Activities 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 + n 10m 237 Np Neutron flux ! 22m 93 T 1/2 = 2.144 × 10 6 yr H 2 O moderator e - -Ta reaction 10 -1 Relative neutron flux(/MeV) 10 -3 10 -5 10 -7 > 1 eV 10 -9 10 -10 10 -8 10 -6 10 -4 10 -2 10 0 10 2 Neutron Energy (MeV) 2007 Symposium on Nuclear Data 10

③ Activities in Japan for keV neutrons: Capture JAEA, Tokyo Tech., Kyoto π Ge 4 π Ge 4 spectrometer spectrometer Linac shielding wall Electron beam BF 3 -counter neutron monitor Water Evacuated moderator flight tubes Lead shadow bar MA Neutron beam sample filters Neutron producing target Concrete Lead 10.0 m Np-237 H 2 BO 3 Am-241 2007 Symposium on Nuclear Data 11 Am-243

Experiments for Capture Experiments for Capture KUR Electron Linear Accelerator Facility 31 μ A Electron beam ： Energy 30 MeV, Ave. Current Rep. Rate 100 Hz, Pulse Width 100 ns π Ge spectrometer 4 π 4 Ge 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 237 Np (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 Data 15

③ Fission Activities in Japan for keV neutrons Tohoku, Kyoto � 237 Np, 241 Am, 242m Am, 243 Am � En=1- 100 keV � 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) 235 U 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 Sample deposit Sample deposit Sample deposit Sample deposit Sample deposit Fission (U-235) (U-235) (U-235) (MA) (MA) (MA) Ar + CO 2 Ar + CO 2 Ar + CO 2 Connector Connector Connector 49 mm 49 mm Electrode Electrode Electrode (anode) (anode) (anode) Ar + CO 2 Ar + CO 2 Ar + CO 2 Chamber Chamber Chamber (aluminum) (aluminum) (aluminum) 43 mm 43 mm 120 100 80 Noise 60 DSP DSP Voltage [ch] 40 Signal 20 0 -20 -40 信号波形 -60 ノイズの代表波形 -80 0 500 1000 Time [ch] • Wave form analysis for each slowing down time • Subtraction of “γ -flash ” noise from raw signal (noise + signal) 2007 Symposium on Nuclear Data 17

④ Problems in measurement for MeV neutrons The data is very limited especially for MeV neutrons. 237 Np capture 10 1 present (=CCONE) JENDL-3.3 ENDF/B-VII.0 Cross Section (b) Nakagawa 2007 10 0 D.C.Stupegia+ ('67) M.Lindner+ ('76) L.W.Weston+ ('81) Ju.N.Trofimov+ ('83) 10 -1 N.N.Buleeva+ ('88) N.N.Buleeva+ ('88) N.N.Buleeva+ ('88) Katsuhei Kobayashi+ ('02) Katsuhei Kobayashi+ ('02) E.I.Esch+ ('05) 10 -2 10 3 10 4 10 5 10 6 10 7 Neutron Energy (eV) 2007 Symposium on Nuclear Data 18

④ Possibilities in Japan for MeV neutrons Activation by fast neutrons at Yayoi 2007 Symposium on Nuclear Data 19

④ Possibilities 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, Abroad CEA ILL n-TOF Integral Yayoi KUR KURRI linac Japan T.I.T. differential 放射線 JRR3 J-PARC JAEA 標準施設 thermal eV keV MeV Neutron Energy 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. 2007 Symposium on Nuclear Data 21