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Journal Articles

Development of inspection and repair techniques for reactor vessel of experimental fast reactor "Joyo"; Replacement of upper core structure

Takamatsu, Misao; Kawahara, Hirotaka; Ito, Hiromichi; Ushiki, Hiroshi; Suzuki, Nobuhiro; Sasaki, Jun; Ota, Katsu; Okuda, Eiji; Kobayashi, Tetsuhiko; Nagai, Akinori; et al.

Nippon Genshiryoku Gakkai Wabun Rombunshi, 15(1), p.32 - 42, 2016/03

In the experimental fast reactor Joyo, it was confirmed that the top of the irradiation test sub-assembly of "MARICO-2" (material testing rig with temperature control) had been broken and bent onto the in-vessel storage rack as an obstacle and had damaged the upper core structure (UCS). This paper describes the results of the in-vessel repair techniques for UCS replacement, which are developed in Joyo. UCS replacement was successfully completed in 2014. In-vessel repair techniques for sodium cooled fast reactors (SFRs) are important in confirming its safety and integrity. In order to secure the reliability of these techniques, it was necessary to demonstrate the performance under the actual reactor environment with high temperature, high radiation dose and remained sodium. The experience and knowledge gained in UCS replacement provides valuable insights into further improvements for In-vessel repair techniques in SFRs.

Journal Articles

New integral experiments for large angle scattering cross section data benchmarking with DT neutron beam at JAEA/FNS

Onishi, Seiki*; Kondo, Keitaro*; Azuma, Tetsushi*; Sato, Satoshi; Ochiai, Kentaro; Takakura, Kosuke; Murata, Isao*; Konno, Chikara

Fusion Engineering and Design, 87(5-6), p.695 - 699, 2012/08

 Times Cited Count:5 Percentile:57.96(Nuclear Science & Technology)

A new integral experiment with a deuteron-triton fusion (DT) neutron beam started in order to validate scattering cross section data. First the DT neutron beam was constructed with a collimator. The characteristics of the DT neutron beam were examined experimentally. Second a new integral experiment for type 316 stainless steel (SS316) was carried out with this DT neutron beam. Reaction rates of the $$^{93}$$Nb(n,2n)$$^{rm 92m}$$Nb reaction on the center of the beam axis and at 15 cm and 30 cm apart from the axis in the assembly were measured with the activation foil method and were calculated with the Monte Carlo transport calculation code MCNP and nuclear data libraries, JENDL-4.0, JENDL-3.3 and ENDF/B-VI.8. The ratios of calculation to experiment became smaller than 1 with the distance from the beam axis for all the nuclear libraries. It was pointed out that the diagonally forward cross section data had some problems.

Journal Articles

Performance analysis of fusion nuclear-data benchmark experiments for light to heavy materials in MeV energy region with a neutron spectrum shifter

Murata, Isao*; Ota, Masayuki*; Miyamaru, Hiroyuki*; Kondo, Keitaro; Yoshida, Shigeo*; Iida, Toshiyuki*; Ochiai, Kentaro; Konno, Chikara

Journal of Nuclear Materials, 417(1-3), p.1127 - 1130, 2011/10

 Times Cited Count:2 Percentile:76.59(Materials Science, Multidisciplinary)

Nuclear data are indispensable for development of fusion reactor candidate materials. However, benchmarking of the nuclear data in MeV energy region is not sufficient even now. In the present study, benchmark performance in the MeV energy region was investigated theoretically in case of experiments by using a 14MeV neutron source. We carried out a systematical analysis for light to heavy materials. As a result, the benchmark performance for neutron spectrum was confirmed to be acceptable, while for $$gamma$$-ray it was not sufficient. This indicates it was effective to use a spectrum shifter. As a shifter beryllium had the best performance. Moreover, it was preliminarily examined whether it is really acceptable that only the spectrum before last collision is considered in the benchmark performance analysis. It was pointed out that not only the last collision but also more previous collisions should be taken into account equally in the benchmark performance analysis.

Journal Articles

Measurement of reaction rates in Li/V-alloy assembly with 14 MeV neutron irradiation

Tanaka, Teruya*; Sato, Satoshi; Kondo, Keitaro; Ochiai, Kentaro; Murata, Isao*; Takakura, Kosuke; Sato, Fuminobu*; Kada, Wataru*; Iida, Toshiyuki*; Konno, Chikara; et al.

Fusion Science and Technology, 60(2), p.681 - 686, 2011/08

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Irradiation experiments of 14 MeV neutrons have been performed on a Li block assembly of 46 $$times$$ 51 $$times$$ 51 cm$$^3$$ with a 5 cm thick V-alloy layer inside to examine the accuracy of neutronics calculations for the Li/V-alloy blanket design. Foils of Nb, Ni, In and Au for reaction rate measurements of $$^{93}$$Nb(n,2n)$$^{rm 92m}$$Nb, $$^{58}$$Ni(n,p)$$^{58}$$Co, $$^{115}$$In(n,n')$$^{rm 115m}$$In, $$^{197}$$Au(n,$$gamma$$)$$^{198}$$Au reactions and $$^6$$Li enriched ($$^6$$Li: 95.5%) and $$^7$$Li enriched ($$^7$$Li: 99.9%) Li$$_2$$CO$$_3$$ pellets for tritium production rate measurements were installed in the assembly. Results of the measurements were compared with those of calculations with MCNP5, JENDL-3.3 and JENDL/D-99. The comparisons for the reaction rates in the Nb, Ni and In foils indicate that measurements and calculations of the fast neutron transport are consistent almost within 10%. In the comparison for the reaction rates in the Au foils, the underestimation of 15% was found at a surface of the V-alloy layer. There is a possibility that this is due to the elastic scattering cross section of V around 4 keV as previously reported. The comparisons for tritium production rates in the $$^6$$Li enriched and $$^7$$Li enriched Li$$_2$$CO$$_3$$ pellets indicate that calculated rates were larger than results of the measurements by 2-8% and 1-4%, respectively.

Journal Articles

Measurement of charged-particle emission double-differential cross section of fluorine for 14.2 MeV neutrons

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Kubota, Naoyoshi*; Miyamaru, Hiroyuki*; Konno, Chikara; Nishitani, Takeo

Journal of Nuclear Science and Technology, 48(8), p.1146 - 1157, 2011/08

 Times Cited Count:3 Percentile:67.22(Nuclear Science & Technology)

We carried out a detailed measurement of the double-differential cross sections of fluorine for emitted protons, deuterons, tritons and $$alpha$$-particles with 14.2 MeV neutron incidence. An improved charged-particle spectrometer with a pencil DT-neutron beam furnished at the FNS facility of Japan Atomic Energy Agency enabled us to obtain precise data with a fine energy resolution in wide energy range and angular range from 15 to 150 $$^{circ}$$. The obtained data were compared with the nuclear data evaluated in JENDL-3.3 and ENDF/B-VII.0. As a result, large differences in the energy and angular distributions of emitted particles and the charged-particle production cross sections were found between the measured and evaluated data. Angular-differential cross sections for several discrete peaks corresponding to excited states of residual nuclei were extracted to discuss the reaction mechanism of charged-particle emission. The obtained data suggest that the charged-particle emission reaction of fluorine has a quite complicated mechanism where both the direct reaction process and the pre-equilibrium process contribute. The present experiment is the first simultaneous measurement of the four different kinds of charged particles and would provide useful data to confirm previous experimental data as well as to establish a nuclear reaction model of fluorine.

Journal Articles

Implementation of a collimated DT neutron beam at the 1st target room of JAEA/FNS for new integral benchmark experiments

Onishi, Seiki; Kondo, Keitaro; Sato, Satoshi; Ochiai, Kentaro; Takakura, Kosuke; Konno, Chikara; Murata, Isao*

Journal of the Korean Physical Society, 59(2), p.1949 - 1952, 2011/08

 Times Cited Count:0 Percentile:100(Physics, Multidisciplinary)

So far we carried out many integral benchmark experiments (in-situ experiments and Time-Of-Flight experiments) for nuclear data with DT neutrons at the Fusion Neutronics Source facility in Japan Atomic Energy Agency. In addition to those, we have a plan to perform new integral benchmark experiments for nuclear data with a DT neutron beam, which can investigate nuclear data for almost the whole angle and the whole energy. Because the large-size tritium target in FNS is difficult to procure, we have started to build a new DT neutron beam with the small tritium target, which is easy to obtain, at the first target room of FNS. We already designed a collimator system for the DT neutron beam based on calculations. In this work, under that design, the collimator was constructed. Then the characteristics of the neutron field were measured in order to confirm the DT neutron beam performance. It was demonstrated that the DT neutron beam was realized as calculated.

Journal Articles

Tracking the behavior of fusion neutrons !!; The Latest research on the double-differential cross sections

Murata, Isao*; Kondo, Keitaro; Miyamaru, Hiroyuki*; Ochiai, Kentaro

Purazuma, Kaku Yugo Gakkai-Shi, 85(11), p.762 - 773, 2009/11

In order to obtain high precision cross-section data, which is indispensable for a fusion reactor design, Osaka University has advanced the development of two of new double-differential cross-section measurement techniques for about ten years through a joint research with Japan Atomic Energy Agency (JAEA). A direct measurement of (n,2n) reaction cross-sections based on neutron emission spectra and a highly accurate charged particle emission double-differential cross-section measurement are realized by using a unique DT neutron pencil beam in the world furnished at the FNS facility of JAEA. This article plainly explains the latest result of the detailed cross-section measurements for beryllium, zirconium and fluorine as well as the outline of the measurement techniques.

Journal Articles

Problems of lead nuclear data in fusion blanket design

Kondo, Keitaro; Murata, Isao*; Klix, A.*; Seidel, K.*; Freiesleben, H.*

Fusion Engineering and Design, 84(7-11), p.1076 - 1086, 2009/06

 Times Cited Count:3 Percentile:71.22(Nuclear Science & Technology)

Several participants of the International Thermonuclear Experimental Reactor (ITER), such as Japan and EU, intend to introduce a Test Blanket Module (TBM) using a liquid lithium lead eutectic, which is used for the neutron multiplier and the tritium breeder. Recently a preliminary experiment in which a LiAlPb assembly was irradiated with 14 MeV neutrons was conducted at Technische Universit$"{a}$t Dresden. We found out that the neutron flux inside the assembly calculated with JENDL-3.3 underestimates an experimental value in the 10-16 MeV region by around 30% and that in the 0.5-5 MeV region by around 15%, while the calculated flux with JEFF-3.1 overestimates the measurement in the 5-10 MeV region by around 20%. In order to reveal a reason of the discrepancy, problems of the nuclear data libraries for lead were investigated. As a result, the following problems of the evaluated libraries were pointed out: The cross sections of the elastic scattering in JENDL-3.3 for lead isotopes are too small and cause a significant underestimation of the neutron flux above 10 MeV, which appeared in the analysis of the above experiment. Inelastic scattering data for $$^{208}$$Pb in JENDL-3.3 reproduce previous experimental double-differential cross section data most well. However, those for the other lead isotopes have some problems and cause a large underestimation of the neutron flux from 0.5 to 5 MeV. The reason of the overestimation in the energy region of 5-10 MeV with JEFF-3.1 is still unclear.

Journal Articles

Direct neutron spectrum measurement to validate $$^{rm nat}$$Zr(n,2n) reaction cross-section at 14 MeV

Murata, Isao*; Shiken, Kimiaki*; Kondo, Keitaro; Matsunaka, Masayuki*; Ota, Masayuki*; Miyamaru, Hiroyuki*; Ochiai, Kentaro; Konno, Chikara; Nishitani, Takeo

Fusion Engineering and Design, 84(7-11), p.1376 - 1379, 2009/06

 Times Cited Count:0 Percentile:100(Nuclear Science & Technology)

Lithium zirconate, Li$$_{2}$$ZrO$$_{3}$$, is known as a candidate blanket material in a fusion reactor. According to the independent benchmark studies for zirconium by JAERI, Kyoto University and Osaka University, the neutron spectrum calculations show fairly large overestimation for most evaluated nuclear data libraries. The author's group expects that the overestimation be due to a problem of evaluation for the (n,2n) reaction, because the (n,2n) reaction cross section is not well determined experimentally. In the present study, two neutrons emitted from $$^{rm nat}$$Zr(n,2n) reaction have been measured directly to reveal the problem. As a result of measurements, the cross section obtained for energies above 1 MeV, which is the lower measurable limit energy, shows a little larger than JENDL-3.3. This is an opposite result to the benchmark analysis. However, an extrapolation for the low energy region by the evaporation spectrum with the nuclear temperature of 1 MeV brought the smaller total (n,2n) reaction cross section than JENDL-3.3, which is comparable to ENDF/B-VI. This result suggests that the discrepancies reported previously might be due to inappropriate evaluation of nuclear temperature.

Journal Articles

Preliminary spectrum shifter design for intermediate energy nuclear data benchmark experiments with DT neutrons

Ota, Masayuki*; Kondo, Keitaro; Matsunaka, Masayuki*; Miyamaru, Hiroyuki*; Murata, Isao*; Iida, Toshiyuki*; Ochiai, Kentaro; Konno, Chikara

Fusion Engineering and Design, 84(7-11), p.1446 - 1449, 2009/06

 Times Cited Count:3 Percentile:71.22(Nuclear Science & Technology)

In order to validate evaluated nuclear data libraries for fusion reactor designs, various integral benchmark experiments with DT neutrons have been carried out so far on structural and advanced blanket materials at the FNS facility of JAEA. In this study, a neutron spectrum shifter, which will be placed between a sample and the DT neutron source to moderate DT neutrons incident to the sample, was adopted in order to carry out the nuclear data benchmarking induced with several MeV neutrons effectively. In order to estimate effects of the spectrum shifter, the ratio of contribution of initial 14 MeV neutrons in leakage neutron and $$gamma$$-ray spectra was calculated for the experimental configuration at FNS with a modified MCNP-4C code. The calculations were carried out for a Li$$_{2}$$TiO$$_{3}$$ sample with a Be, LiD, or D$$_{2}$$O spectrum shifter. It was found that the Be shifter was superior to others and the contribution of initial 14 MeV neutrons varied depending on material and size of the sample and shifter. The present analysis also suggested that the Be shifter was effective for secondary $$gamma$$-ray experiments.

Journal Articles

Verification of KERMA factor for beryllium at neutron energy of 14.2 MeV based on charged-particle measurement

Kondo, Keitaro; Ochiai, Kentaro; Murata, Isao*; Konno, Chikara

Fusion Engineering and Design, 83(10-12), p.1674 - 1677, 2008/12

 Times Cited Count:5 Percentile:58.28(Nuclear Science & Technology)

In previous direct measurements of nuclear heating for beryllium induced with DT-neutrons, it was pointed out that the calculation with JENDL-3.2 underestimated the measured one by 25 %. However, reasons of this large discrepancy have not been understood clearly. In order to reveal the reason of this discrepancy, we examined KERMA factors for beryllium deduced with three latest nuclear data libraries: JENDL-3.3, ENDF/B-VII.0 and JEFF-3.1. As a result, the partial KERMA factors for $$^{9}$$Be(n,2n+2$$alpha$$) reaction channel at incident neutron energy of 14.2 MeV deduced from JENDL-3.3 was significantly smaller than that deduced from the other libraries. These partial KERMA factors were compared with a new partial KERMA factor calculated based on our experimental model from our recent measurement of the $$alpha$$-particle emission double-differential cross-section for beryllium. The partial KERMA factor from JENDL-3.3 was smaller by 20 % than our experiment-based one. The reason of the discrepancy in the previous nuclear heating measurement comes from smaller partial KERMA factor for beryllium in JENDL-3.3, which is caused by significant underestimation of higher energy part of $$alpha$$-particle emission DDX at forward emission angles.

Journal Articles

Angle-correlated spectrum measurement for two neutrons emitted from (n,2n) reaction with the coincidence detection technique using a pencil-beam DT neutron source

Murata, Isao*; Takagi, Satoshi*; Kondo, Keitaro; Shiken, Kimiaki*; Miyamaru, Hiroyuki*; Mitsuda, Motoyuki; Maekawa, Fujio; Ochiai, Kentaro; Nishitani, Takeo

Nuclear Instruments and Methods in Physics Research A, 595(2), p.439 - 446, 2008/10

 Times Cited Count:3 Percentile:68.1(Instruments & Instrumentation)

A technique was developed to measure the angle-correlated neutron energy spectrum with the coincidence detection technique using a pencil-beam DT neutron source at the Fusion Neutronics Source (FNS) of the Japan Atomic Energy Agency (JAEA). Triple differential cross-sections of the $$^{55}$$Mn(n,2n) reaction were measured first, from which the total $$^{55}$$Mn(n,2n) reaction cross-section was deduced and compared with JENDL-3.3. The agreement was sufficient to prove the validity of the technique. With the present measuring technique, a complete measurement of a medium-heavy or heavy element such as manganese would become possible through several measurements, because the angle dependence of the emitted neutrons from it is normally weak. The technique will be a useful tool for measuring the angle-correlated neutron spectrum of light elements such as beryllium for investigation of their complicated nuclear reaction mechanism.

Journal Articles

What is really happening in the wall?

Murata, Isao*; Konno, Chikara

Nippon Genshiryoku Gakkai-Shi, 50(9), p.574 - 579, 2008/09

Charged particles confined in the plasma hurtle to the first wall in fusion reactors. They lose their energy immediately and do not enter the first wall so deeply. On the other hand, many neutrons are produced in the plasma by the fusion reaction. Because neutrons has no charge, they are prone to penetrate the wall. Their energy is high (about 14 MeV) and they can come up to the deeper position of the wall. They arrive to the blanket region rear of the first wall and cause various interactions (nuclear reactions). Here we will explain what is really happening there with neutron reactions and numerical simulation.

Journal Articles

High-magnetic-field X-ray absorption spectroscopy of field-induced valence transition in EuNi$$_2$$(Si$$_{1-x}$$Ge$$_x$$)$$_2$$

Matsuda, Yasuhiro*; Inami, Toshiya; Owada, Kenji; Murata, Yuto*; Nojiri, Hiroyuki*; Murakami, Yoichi*; Mitsuda, Akihiro*; Wada, Hirofumi*; Miyazaki, Hiroshi*; Harada, Isao*

Journal of the Physical Society of Japan, 77(5), p.054713_1 - 054713_7, 2008/05

 Times Cited Count:24 Percentile:22.78(Physics, Multidisciplinary)

The magnetic-field-induced valence transition in EuNi$$_2$$(Si$$_{1-x}$$Ge$$_x$$)$$_2$$ (x=0.82, 0.85) has been studied by X-ray absorption spectroscopy at low temperatures. The field dependence of the Eu valence is directly observed for the first time. We find a significant decrease in the valences at high magnetic fields above 40 T. The valence of Eu changes from v = 2.75 at a zero field to v = 2.33 at 40 T for x = 0.82. The results are analyzed using a theoretical model. The hybridization parameter V between the Eu$$^{2+}$$ and Eu$$^{3+}$$ states and the energy separation $$Delta$$$$E$$ are determined, which are crucial for quantum mechanical mixing.

Journal Articles

Experimental study on breakup reaction of beryllium and carbon induced with 14-MeV neutrons based on emitted charged-particle measurements

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Miyamaru, Hiroyuki*; Kubota, Naoyoshi*; Konno, Chikara; Nishitani, Takeo

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.1, p.407 - 410, 2008/05

Beryllium and carbon are candidate materials of fusion reactors and the $$^{9}$$Be(n,2n+2$$alpha$$) and $$^{12}$$C(n,n'+3$$alpha$$) reactions are important from engineering requirements. In order to estimate double-differential cross sections (DDX) for emitted particles, we have to accurately grasp details of the reaction mechanism. Understanding of the reaction mechanism is also interesting from a viewpoint of nuclear physics. Recently we developed a new spectrometry system with a pencil-beam DT neutron source. Using the system, we carried out detailed measurements of DDX for $$alpha$$-particles emitted from beryllium and carbon. The reaction mechanism was investigated by a Monte Carlo calculation of DDX. For the $$^{9}$$Be(n,2n+2$$alpha$$) reaction, the result suggests importance of the contribution from the $$^{9}$$Be(n,$$alpha$$)$$^{6}$$He*(Ex$$geq$$1.8MeV) reaction. For the $$^{12}$$C(n,n'+3$$alpha$$) reaction, the contribution from the $$^{12}$$C(n,$$alpha$$)$$^{9}$$Be*(Ex$$geq$$2.43MeV) reaction was appeared and its ratio was investigated to explain the shape of DDX for neutrons in lower energy.

Journal Articles

Measurement of the angle-correlated neutron spectrum for the $$^{9}$$Be(n,2n) reaction with a pencil-beam DT neutron source

Murata, Isao*; Takagi, Satoshi*; Shiken, Kimiaki*; Kondo, Keitaro; Miyamaru, Hiroyuki*; Ochiai, Kentaro; Nishitani, Takeo; Konno, Chikara

Proceedings of International Conference on Nuclear Data for Science and Technology (ND 2007), Vol.2, p.999 - 1002, 2008/05

The (n,2n) reaction plays a very important role in the design of fusion reactor. In the present study, using a pencil-beam DT neutron source, angle-correlated two neutrons emitted through (n,2n) reaction have directly been measured to determine (n,2n) reaction cross section with the coincidence detection technique for beryllium which is the most important element in the fusion reactor. In the experiment, two NE213 detectors were arranged very close to the sample to efficiently measure the two neutrons. The measured spectra were unfolded by FORIST with the detector response matrix evaluated by SCINFUL. As a relust, comparing with the evaluations of ENDF/B-VI and JENDL-3.3 for energies above 800 keV of the lower measurable limit energy, the shape of derived angula-differential cross-section fits JENDL-3.3 better than ENDF/B-VI. However, agreement of the cross section of (n,2n) above 800 keV was acceptable within 10 percents for both libraries.

Journal Articles

Measurement and analysis of neutron-induced alpha particle emission double-differential cross section of carbon at 14.2 MeV

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Kubota, Naoyoshi*; Miyamaru, Hiroyuki*; Konno, Chikara; Nishitani, Takeo

Journal of Nuclear Science and Technology, 45(2), p.103 - 115, 2008/02

 Times Cited Count:7 Percentile:47.6(Nuclear Science & Technology)

We carried out a detailed measurement of neutron induced $$alpha$$-particle emission double-differential cross-section of carbon at 14.2 MeV, for which there were few measured data in spite of its importance in many applications. The obtained cross-section for the $$^{12}$$C(n,$$alpha_{0}$$)$$^{9}$$Be$$_{(ground state)}$$ reaction agreed well with previous experiments and evaluated nuclear data. The obtained angular-differential cross-section of the $$^{12}$$C(n,n'+3$$alpha$$) reaction for $$alpha$$-particles showed a strong forward-peaked distribution that suggested significant contribution of the direct reaction process to the 3$$alpha$$ breakup. We attempted to calculate the emitted particle spectra by means of a Monte Carlo method and estimate the branching ratio of the channels which contribute to the $$^{12}$$C(n,n'+3$$alpha$$) reaction. As a result, it was found that the $$^{12}$$C(n,$$alpha$$)$$^{9}$$Be* channels play an important role in generating the experimental double-differential cross-section both of emitted $$alpha$$-particles and neutrons. The estimated ratio of the $$^{12}$$C(n,$$alpha$$)$$^{9}$$Be* channels was around 40%, somewhat larger than those evaluated in previous studies.

Journal Articles

Verification of nuclear data for DT neutron induced charged-particle emission reaction of light nuclei

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Kubota, Naoyoshi; Miyamaru, Hiroyuki*; Takagi, Satoshi*; Shido, Shoichi*; Konno, Chikara; Nishitani, Takeo

Fusion Engineering and Design, 82(15-24), p.2786 - 2793, 2007/10

 Times Cited Count:2 Percentile:78.37(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Charged-particle spectrometry using a pencil-beam DT neutron source for double-differential cross-section measurement

Kondo, Keitaro; Murata, Isao*; Ochiai, Kentaro; Miyamaru, Hiroyuki*; Kubota, Naoyoshi; Takagi, Satoshi*; Shido, Shoichi*; Takahashi, Akito*; Nishitani, Takeo

Nuclear Instruments and Methods in Physics Research A, 568(2), p.723 - 733, 2006/12

 Times Cited Count:14 Percentile:25.29(Instruments & Instrumentation)

Deuteron-tritium (DT) neutron induced charged-particle emission double-differential cross section (DDXc) is quite important to estimate nuclear heating, material damages for a fusion reactor. In order to realize the accurate measurement of the DDXc data especially for light nuclei, we propose a unique spectrometer system and a data processing method in this paper. The spectrometer overcomes the fundamental difficulty of the DDXc measurement with a pencil-beam neutron source and a counter telescope consisting of silicon surface barrier detectors. A superior S/N ratio, fine energy and angular resolutions, a wide detection energy range, and a excellent particle discrimination are realized. In order to confirm the validity of the spectrometer, measurements of the emitted $$alpha$$-particle from $$^{27}$$Al(${it n,x$alpha$}$) reaction and the recoiled proton from $$^{1}$$H(${it n,n}$) reaction are carried out. Based on the results, we conclude the validity and the superiority of the present spectrometry technique.

JAEA Reports

Development of measurement technique for charged-particle emission double-differential cross section using pencil-beam neutron source (Cooperative research)

Kondo, Keitaro; Ochiai, Kentaro; Kubota, Naoyoshi; Nishitani, Takeo; Murata, Isao*; Miyamaru, Hiroyuki*; Takahashi, Akito*

JAEA-Research 2006-016, 50 Pages, 2006/03

JAEA-Research-2006-016.pdf:6.25MB

Charged-particle emission double- differential cross section (DDXc) is quite important to estimate nuclear heating, material damages of a fusion reactor. We have developed a new technique for detailed measurement of DDXc. The technique overcomes fundamental difficulties of DDXc measurement with a pencil-beam neutron source and a counter telescope consisting of silicon surface barrier detectors. A superior S/N ratio, fine energy and angular resolutions, a wide detection energy range, and an excellent particle discrimination are realized together with a reasonable measurement time. In order to confirm the validity of the spectrometer, measurements of the emitted $$alpha$$-particle from $$^{27}$$Al(n,x$$alpha$$) reaction and the recoiled proton from $$^{1}$$H(n,n) reaction are carried out. Based on the results, we conclude the validity and the superiority of the present spectrometry technique.

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