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Journal Articles

Polarization analysis for small-angle neutron scattering with a $$^{3}$$He spin filter at a pulsed neutron source

Okudaira, Takuya; Ueda, Yuki; Hiroi, Kosuke; Motokawa, Ryuhei; Inamura, Yasuhiro; Takata, Shinichi; Oku, Takayuki; Suzuki, Junichi*; Takahashi, Shingo*; Endo, Hitoshi*; et al.

Journal of Applied Crystallography, 54(2), p.548 - 556, 2021/04

 Times Cited Count:0 Percentile:0.02(Chemistry, Multidisciplinary)

Neutron polarization analysis (NPA) for small-angle neutron scattering (SANS) experiments using a pulsed neutron source was successfully achieved by applying a $$^{3}$$He spin filter as a spin analyzer for the scattered neutrons. The $$^{3}$$He spin filter covers a sufficient solid angle for performing SANS experiments, and the relaxation time of the $$^{3}$$He polarization is sufficient for continuous use over a few days, thus reaching the typical duration required for a complete set of SANS experiments. Although accurate evaluation of the incoherent neutron scattering, which is predominantly attributable to hydrogen atoms in samples, is practically difficult using calculations based on the sample elemental composition, the developed NPA approach with consideration of the influence of multiple neutron scattering enabled reliable decomposition of the SANS intensity distribution into the coherent and incoherent scattering components. To date, NPA has not been well established as a standard technique for SANS experiments at pulsed neutron sources. This work is anticipated to greatly contribute to the accurate determination of the coherent neutron scattering component for scatterers in various types of organic sample systems in SANS experiments at J-PARC.

Journal Articles

Development and application of a $$^3$$He neutron spin filter at J-PARC

Okudaira, Takuya; Oku, Takayuki; Ino, Takashi*; Hayashida, Hirotoshi*; Kira, Hiroshi*; Sakai, Kenji; Hiroi, Kosuke; Takahashi, Shingo*; Aizawa, Kazuya; Endo, Hitoshi*; et al.

Nuclear Instruments and Methods in Physics Research A, 977, p.164301_1 - 164301_8, 2020/10

 Times Cited Count:4 Percentile:76.41(Instruments & Instrumentation)

Journal Articles

Evaluation of oxidation efficiency of hydrophobic palladium catalyst for $$^{3}$$H monitoring in radioactive gaseous waste

Furutani, Misa; Kometani, Tatsunari; Nakagawa, Masahiro; Ueno, Yumi; Sato, Junya; Iwai, Yasunori*

Hoken Butsuri (Internet), 55(2), p.97 - 101, 2020/06

Herein, an oxidation catalyst was introduced after heating it to 600$$^{circ}$$C to oxidize tritium gas (HT) existing in exhaust into tritiated water vapor (HTO). This study aims to establish a safer $$^{3}$$H monitoring system by lowering the heating temperature required for the catalyst. In these experiments, which were conducted in the Nuclear Science Research Institute, Japan Atomic Energy Agency, cupric oxide, hydrophobic palladium/silicon dioxide (Pd/SiO$$_{2}$$), and platinum/aluminum oxide (Pt/Al$$_{2}$$O$$_{3}$$) catalysts were ventilated using standard hydrogen gas. After comparing the oxidation efficiency of each catalyst at different temperatures, we found that the hydrophobic Pd/SiO$$_{2}$$ and Pt/Al$$_{2}$$O$$_{3}$$ catalysts could oxidize HT into HTO at 25$$^{circ}$$C.

Journal Articles

Measurement of the angular distribution of $$gamma$$-rays after neutron capture by $$^{139}$$La for a T-violation search

Okudaira, Takuya; Shimizu, Hirohiko*; Kitaguchi, Masaaki*; Hirota, Katsuya*; Haddock, C. C.*; Ito, Ikuya*; Yamamoto, Tomoki*; Endo, Shunsuke*; Ishizaki, Kohei*; Sato, Takumi*; et al.

EPJ Web of Conferences, 219, p.09001_1 - 09001_6, 2019/12

Parity violating effects enhanced by up to 10$$^6$$ times have been observed in several neutron induced compound nuclei. There is a theoretical prediction that time reversal (T) violating effects can also be enhanced in these nuclei implying that T-violation can be searched for by making very sensitive measurements. However, the enhancement factor has not yet been measured in all nuclei. The angular distribution of the (n,$$gamma$$) reaction was measured with $$^{139}$$La by using a germanium detector assembly at J-PARC, and the enhancement factor was obtained. From the result, the measurement time to achieve the most sensitive T-violation search was estimated as 1.4 days, and a 40% polarized $$^{139}$$La target and a 70% polarized $$^3$$He spin filter whose thickness is 70 atm$$cdot$$cm are needed. Therefore high quality $$^3$$He spin filter is developed in JAEA. The measurement result of the (n,$$gamma$$) reaction at J-PARC and the development status of the $$^3$$He spin filter will be presented.

Journal Articles

JAEA-ISCN development programs of advanced NDA technologies of nuclear material

Seya, Michio; Kobayashi, Naoki; Naoi, Yosuke; Hajima, Ryoichi; Soyama, Kazuhiko; Kureta, Masatoshi; Nakamura, Hironobu; Harada, Hideo

Book of Abstracts, Presentations and Papers of Symposium on International Safeguards; Linking Strategy, Implementation and People (Internet), 8 Pages, 2015/03

JAEA-ISCN has been implementing basic development programs of the advanced NDA technologies for nuclear material (NM) since 2011JFY (Japanese Fiscal Year), which are (1) NRF (Nuclear resonance fluorescence) NDA technology using laser Compton scattered (LCS) $$gamma$$-rays (intense mono-energetic $$gamma$$-rays), (2) Alternative to $$^{3}$$He neutron detection technology using ZnS/B$$_{2}$$O$$_{3}$$ ceramic scintillator, and (3) NRD (Neutron resonance densitometry) using NRTA (Neutron resonance transmission analysis) and NRCA (Neutron resonance capture analysis). These programs are going to be finished in 2014JFY and have demonstration tests in February - March 2015.

Journal Articles

Introduction to development of advanced safeguards and security NDA technologies by JAEA-ISCN

Seya, Michio; Kureta, Masatoshi; Soyama, Kazuhiko; Nakamura, Hironobu; Harada, Hideo; Hajima, Ryoichi

Proceedings of INMM 55th Annual Meeting (Internet), 10 Pages, 2014/07

JAEA has been implementing development programs of basic technologies of the following advanced NDA (non-destructive assay) of nuclear material (NM) for nuclear safeguards and security. (1) Alternative to $$^{3}$$He neutron detection using ZnS/B$$_{2}$$O$$_{3}$$ ceramic scintillator, (2) NRD (neutron resonance densitometry) using NRTA (neutron resonance transmission analysis) and NRCA (neutron resonance capture analysis), (3) NRF (nuclear resonance fluorescence)-NDA using laser Compton scattered (LCS) $$gamma$$-rays (intense mono-energetic $$gamma$$-rays). The development program (1) is for NDA systems that use ZnS/B$$_{2}$$O$$_{3}$$ ceramic scintillator as alternative neutron detector to $$^{3}$$He for coming shortage of its supply. The program (2) is for a NDA system of isotopic composition measurement (non-destructive mass spectroscopy) in targets such as particle-like melted fuel debris using NRTA and NRCA. The program (3) is for NDA systems using a specific NRF reaction of certain Pu/U isotope caused by mono-energetic LCS $$gamma$$-ray with energy tuned to the specific excited state of the isotope. This paper introduces above three programs.

Journal Articles

Novel instrument system for discriminating secondary particles in high-spatial-resolution neutron detection

Yamagishi, Hideshi; Nakamura, Tatsuya; Soyama, Kazuhiko; Masaoka, Sei; Aizawa, Kazuya

Review of Scientific Instruments, 75(7), p.2340 - 2345, 2004/07

 Times Cited Count:9 Percentile:47.59(Instruments & Instrumentation)

A new instrument system with the capability of secondary-particle discrimination (InSPaD) was studied for the development of two-dimensional neutron detectors (2D-ND) filled with helium-3 gas and with high spatial resolution. The InSPaD can discriminate between the tracks of a proton and a triton created in the nuclear reaction $$^{3}$$He(${it n}$,${it p}$)${it T}$ by simply setting the level of discriminators appropriately in each signal channel, and the system exhibits a high spatial resolution, high counting rate, low background, and stability. The simulations of the 2D-ND equipped with the InSPaD revealed spatial resolutions of 0.46 mm in full width at half maximum for a 10% mixture of C$$_{2}$$H$$_{6}$$ with helium-3 at 0.3 MPa. The results of neutron-detection experiments using a microstrip gas chamber, including the range of the secondary particles and the pulse-height distribution, agreed well with the simulated results, indicating the feasibility of the InSPaD.

Journal Articles

Measurement of depth distributions of $$^{3}$$H and $$^{14}$$C induced in concrete shielding of an electron accelerator facility

Endo, Akira; Harada, Yasunori; Kawasaki, Katsuya; Kikuchi, Masamitsu

Applied Radiation and Isotopes, 60(6), p.955 - 958, 2004/06

 Times Cited Count:5 Percentile:36.97(Chemistry, Inorganic & Nuclear)

no abstracts in English

Journal Articles

t+$$^{3}$$He molecular structures in $$^{6}$$Li studied ($$^{3}$$He,$$alpha$$) reaction at 450 MeV

Nakayama, Shintaro*; Yamagata, Tamio*; Akimune, Hidetoshi*; Fujiwara, Mamoru; Fushimi, Kenichi*; Greenfield, M. B.*; Hara, Keigo*; Hara, Kaoru*; Hashimoto, Hisanobu*; Ichihara, Kayoko*; et al.

Nuclear Physics A, 731, p.355 - 362, 2004/02

 Times Cited Count:0 Percentile:0.01(Physics, Nuclear)

no abstracts in English

Journal Articles

Investigation of IVGRs via the $$^{58}$$Ni(t,$$^{3}$$He)$$^{58}$$Co reaction

Guillot, J.*; Beaumel, D.*; Van den Berg, A. M.*; Brandenburg. S.*; Davids, B.*; Fortier, S.*; Fujiwara, Mamoru; Gal$`e$s, S.*; Harakeh, M. N.*; Hunyadi, M.*; et al.

Nuclear Physics A, 731, p.106 - 113, 2004/02

 Times Cited Count:4 Percentile:32.11(Physics, Nuclear)

no abstracts in English

Journal Articles

Neutron-skin thickness in neutron-rich isotopes

Krasznahorkay, A.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Blasi, N.*; Brandenburg. S.*; Csatl$'o$s, M.*; Fujiwara, Mamoru; Guly$'a$s, J.*; Harakeh, M. N.*; Hunyadi, M.*; et al.

Nuclear Physics A, 731, p.224 - 234, 2004/02

 Times Cited Count:62 Percentile:93.74(Physics, Nuclear)

no abstracts in English

Journal Articles

Feasibility of D$$^{3}$$He/ST fusion power reactor

Shimotono, Hidetoshi*; Nishio, Satoshi; Kondo, Shunsuke*

Fusion Engineering and Design, 69(1-4), p.675 - 681, 2003/09

 Times Cited Count:3 Percentile:26.72(Nuclear Science & Technology)

The prospect of D$$^{3}$$He/ST fusion power reactor have been explored and the design window of the reactor has been specified. The high temperature super-conductor (Bi2212/Ag/Ag) is chosen for TF coils; the operation temperature is 20 K; the conductor current density is about 110 MA/m$$^{2}$$ at 18-23 T. System analyses have indicated that the design window (which satisfies the constraints HH$$_{y2}$$$$leq$$2, ${it n}$$$_{e}$$/${it n}$$$_{GW}$$$$<$$1.1, and $$sigma$$TF$$leq$$800MPa) is amall and require ${it A}$$$>$$1.55, $$beta$$$$_{t}$$$$leq$$40%, and the first wall thermal losd ${it P}$$$_{w}$$$$<$$1.25 MW/m$$^{2}$$ to ensure the functional and structural reliabilities of the center column (i.e. TF coil system). The plasma current is 75-85 MA.

Journal Articles

Influence of superfluidity on recombination reactions of H+T$$rightarrow$$HT and T+T$$rightarrow$$T$$_{2}$$ in $$^{3}$$He-$$^{4}$$He quantum media under saturated vapor pressure at 1.6 K

Aratono, Yasuyuki; Iguchi, Kazunari; Okuno, Kenji*; Kumada, Takayuki

Journal of Physical Chemistry A, 107(19), p.3741 - 3746, 2003/05

 Times Cited Count:4 Percentile:12.38(Chemistry, Physical)

An influence of superfluidity on recombination reactions of H+T$$rightarrow$$HT, T+T$$rightarrow$$T$$_{2}$$ in $$^{3}$$He-$$^{4}$$He quantum media was studied under saturated vapor pressure at 1.6 K. A change of reaction mechanism was observed at transition point from normalfluid to superfluid phase. Tunneling reaction mechanism by H and T bubble atoms was proposed on the basis of large isotope effect.

Journal Articles

Excitation and decay of the Isovector giant monopole resonances via the $$^{208}$$Pb($$^{3}$$He,${it tp}$) reaction at 410 MeV

Zegers, R. G. T.; Abend, H.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Fujimura, Hisako*; Fujita, Hirohiko*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Gal$`e$s, S.*; Hara, Keigo*; et al.

Physical Review Letters, 90(20), p.202501_1 - 202501_4, 2003/05

 Times Cited Count:46 Percentile:85.12(Physics, Multidisciplinary)

no abstracts in English

Journal Articles

Distribution of the Gamow-Teller strength in $$^{90}$$Nb and $$^{208}$$Bi

Krasznahorkay, A.*; Akimune, Hidetoshi*; Fujiwara, Mamoru; Harakeh, M. N.*; J$"a$necke, J.*; Rodin, V. A.*; Urin, M. H.*; Yosoi, Masaru*

Physical Review C, 64(6), p.067302_1 - 067302_4, 2001/12

 Times Cited Count:29 Percentile:82.47(Physics, Nuclear)

no abstracts in English

Journal Articles

Simulation of $$^{3}$$He minority Ion Cyclotron Range of Frequency (ICRF) Heating in International Thermonuclear Experimental Reactor (ITER)

Matsumoto, Hiroshi

Japanese Journal of Applied Physics, Part 2, 40(11A), p.L1187 - L1189, 2001/11

 Times Cited Count:0 Percentile:0(Physics, Applied)

$$^{3}$$He minority ICRF Heating in ITER was simulated by the 1.5 D tokamak simulation code PRETOR and ICRF heating simulation code PION. It was found that the best heating efficiency in terms of the fusion power output is achieved with the smallest miority concentration ratio、0.5%, when the fuel dilution effect by the minority ions was taken into account. The overall heating efficiency is insensitive to the location of the resonance layer over a wide range of the minor radius position. Very efficient heating of the ITER plasma with $$^{3}$$He minority ICRF heating by spreading the RF depostion at three resonant locations was demonstarted by the PRETOR/PION simulation. In the Q=10 reference operation regime, ICRF is better than NBI by 8%, better than pure electron heating by 20%. In the low density region, ICRF is better than NBI by 15%, and better than electron heating by 50%.

Journal Articles

Evidence for a 3.8 MeV state in $$^{9}$$B

Akimune, Hidetoshi*; Fujimura, Hisako*; Fujiwara, Mamoru; Hara, Keigo*; Ishikawa, Takatsugu*; Kawabata, Takahiro*; Utsunomiya, Hiroaki*; Yamagata, Tamio*; Yamasaki, Kaoru*; Yosoi, Masaru*

Physical Review C, 64(4), p.041305_1 - 041305_4, 2001/10

 Times Cited Count:19 Percentile:73.71(Physics, Nuclear)

no abstracts in English

Journal Articles

Observation of the isovector giant monopole resonances in the ($$^{3}$$He, t) reaction

Zegers, R. G. T.*; Van den Berg, A. M.*; Brandenburg. S.*; Fleurot, F. R. R.*; Fujiwara, Mamoru; Guillot, J.*; Hannen, V. M.*; Harakeh, M. N.*; Laurent, H.*; Van der Schaaf, K.*; et al.

Nuclear Physics A, 687(3-4), p.262c - 269c, 2001/05

no abstracts in English

Journal Articles

Excitation of the isovector giant monopole resonances via the $$^{nat}$$Pb($$^{3}$$He, tp) reaction

Zegers, R. G. T.*; Van den Berg, A. M.*; Brandenburg. S.*; Fujiwara, Mamoru; Guillot, J.*; Harakeh, M. N.*; Laurent, H.*; Van der Werf, S. Y.*; Willis, A.*; Wilschut, H. W.*

Physical Review C, 63(3), p.034613_1 - 034613_11, 2001/03

 Times Cited Count:15 Percentile:67.88(Physics, Nuclear)

no abstracts in English

Journal Articles

Structure of the 11/2$$^{-}$$ analog state in $$^{91}$$Nb populated by the $$^{90}$$Zr($$alpha$$, t) reaction

Van der Molen, H. K. T.*; Akimune, Hidetoshi*; Van den Berg, A. M.*; Daito, Izuru*; Fujimura, Hisako*; Fujita, Yoshitaka*; Fujiwara, Mamoru; Harakeh, M. N.*; Ihara, F.*; Inomata, Toru*; et al.

Physics Letters B, 502(1-4), p.1 - 8, 2001/03

 Times Cited Count:3 Percentile:28.74(Astronomy & Astrophysics)

no abstracts in English

65 (Records 1-20 displayed on this page)