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Journal Articles

Experimental analysis of neutron and background $$gamma$$-ray energy spectra of 80-400 MeV $$^{7}$$Li(p,n) reactions under the quasi-monoenergetic neutron field at RCNP, Osaka University

Iwamoto, Yosuke; Sato, Tatsuhiko; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwase, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*

EPJ Web of Conferences, 153, p.08019_1 - 08019_3, 2017/09

 Times Cited Count:0 Percentile:0.03

To develop 100-400 MeV quasi-monoenergetic neutron field, we measured neutron and unexpected $$gamma$$-ray energy spectra of the $$^{7}$$Li(p,n) reaction with 80-389 MeV protons in the 100-m time-of-flight (TOF) tunnel at the Research Center for Nuclear Physics (RCNP). Neutron energy spectra with energies above 3 MeV were measured by the TOF method and $$gamma$$ energy spectra with energies above 0.1 MeV were measured by the automatic unfolding function of the radiation dose monitor DARWIN. For neutron spectra, the contribution of peak intensity to the total intensity integrated with energies above 3 MeV varied between 0.38 and 0.48. For $$gamma$$-ray spectra, high-energetic $$gamma$$-rays at around 70 MeV originated from the decay of $$pi$$$$^{0}$$ were observed over 200 MeV. For the 246-MeV proton incident reaction, the contribution of $$gamma$$-ray dose to neutron dose is negligible because the ratio of $$gamma$$-ray to neutron is 0.014.

Journal Articles

Characterization of the PTW 34031 ionization chamber (PMI) at RCNP with high energy neutrons ranging from 100 - 392 MeV

Theis, C.*; Carbonez, P.*; Feldbaumer, E.*; Forkel-Wirth, D.*; Jaegerhofer, L.*; Pangallo, M.*; Perrin, D.*; Urscheler, C.*; Roesler, S.*; Vincke, H.*; et al.

EPJ Web of Conferences, 153, p.08018_1 - 08018_5, 2017/09

 Times Cited Count:0 Percentile:0.03

At CERN, gas-filled ionization chambers PTW-34031 (PMI) are commonly used in radiation fields including neutrons, protons and $$gamma$$-rays. A response function for each particle is calculated by the radiation transport code FLUKA. To validate a response function to high energy neutrons, benchmark experiments with quasi mono-energetic neutrons have been carried out at RCNP, Osaka University. For neutron irradiation with energies below 200 MeV, very good agreement was found comparing the FLUKA simulations and the measurements. In addition it was found that at proton energies of 250 and 392 MeV, results calculated with neutron sources underestimate the experimental data due to a non-negligible gamma component originating from the target $$^{7}$$Li(p,n)Be reaction.

Journal Articles

Shielding experiments of concrete and iron for the 244 MeV and 387 MeV quasi-mono energetic neutrons using a Bonner sphere spectrometer (at RCNP, Osaka Univ.)

Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Iwase, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Hagiwara, Masayuki*; Yashima, Hiroshi*; Yashima, Hiroshi*; Shima, Tatsushi*; et al.

EPJ Web of Conferences, 153, p.08016_1 - 08016_3, 2017/09

 Times Cited Count:0 Percentile:61.28

Neutron energy spectra behind concrete and iron shields were measured for quasi-monoenergetic neutrons above 200 MeV using a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the $$^{7}$$Li(p,xn) reaction with 246-MeV and 389-MeV protons. The response function of BSS was also measured at neutron energies from 100 MeV to 387 MeV. In data analysis, the measured response function was used and the multiple neutron scattering effect between the BSS and the shielding material was considered. The neutron energy spectra behind the concrete and iron shields were obtained by the unfolding method using the MAXED code. Ambient dose equivalents were obtained as a function of a shield thickness successfully. For the case of the 244 MeV neutron incidence, the multiple neutron scattering effect on the effective dose is large under 50 cm thickness of the concrete shield.

Journal Articles

Neutron spectrometry and dosimetry in 100 and 300 MeV quasi-mono-energetic neutron field at RCNP, Osaka University, Japan

Mares, V.*; Trinkl, S.*; Iwamoto, Yosuke; Masuda, Akihiko*; Matsumoto, Tetsuro*; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Shima, Tatsushi*; Nakamura, Takashi*

EPJ Web of Conferences, 153, p.08020_1 - 08020_3, 2017/09

 Times Cited Count:5 Percentile:94.1

To validate response of an extended range Bonner Sphere Spectrometer (ERBSS) with $$^{3}$$He proportional counter, neutron energy spectra were measured using an ERBSS in the quasi-mono-energetic neutron field at the Research Center for Nuclear Physics (RCNP). Using 100 MeV and 296 MeV proton beams, neutron fields with nominal peak energies of 96 MeV and 293 MeV were generated via $$^{7}$$Li(p,n)$$^{7}$$Be reactions. The energy spectra were measured at a distance of 35 m from the target. To deduce the corresponding neutron spectra from thermal to the nominal maximum energy, the ERBSS data were unfolded using the MSANDB unfolding code. At high energies, the neutron spectra were also measured by means of the TOF method using NE213 organic liquid scintillators. The agreement between ERBSS and TOF neutron spectra above 5 MeV is very good. Comparison in terms of ambient dose equivalent, H$$^{*}$$(10) between ERBSS and TOF values for both proton energies shows very good agreement.

Journal Articles

Applicability of the two-angle differential method to response measurement of neutron-sensitive devices at the RCNP high-energy neutron facility

Masuda, Akihiko*; Matsumoto, Tetsuro*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Sato, Tatsuhiko; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nishiyama, Jun*; et al.

Nuclear Instruments and Methods in Physics Research A, 849, p.94 - 101, 2017/03

 Times Cited Count:0 Percentile:10.71(Instruments & Instrumentation)

Quasi-monoenergetic high-energy neutron fields induced by $$^{7}$$Li(p,n) reactions are used for the response evaluation of neutron-sensitive devices. The quasi-monoenergetic high-energy field consists of high-energy monoenergetic peak neutrons and unwanted continuum neutrons down to the low-energy region. A two-angle differential method has been developed to compensate for the effect of the continuum neutrons in the response measurements. In this study, the two-angle differential method was demonstrated for Bonner sphere detectors, which are typical examples of moderator-based neutron-sensitive detectors, to investigate the method's applicability and its dependence on detector characteristics. Through this study, the adequacy of the two-angle differential method was experimentally verified, and practical suggestions were made pertaining to this method.

Journal Articles

Characterization of high-energy quasi-monoenergetic neutron energy spectra and ambient dose equivalents of 80-389 MeV $$^{7}$$Li(p,n) reactions using a time-of-flight method

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Araki, Shohei*; Yashima, Hiroshi*; Sato, Tatsuhiko; Masuda, Akihiko*; Matsumoto, Tetsuro*; Nakao, Noriaki*; Shima, Tatsushi*; et al.

Nuclear Instruments and Methods in Physics Research A, 804, p.50 - 58, 2015/12

 Times Cited Count:22 Percentile:87.32(Instruments & Instrumentation)

We have measured neutron energy spectra for the 80, 100 and 296 MeV proton incident reactions at the RCNP cyclotron facility using time-of-flight method. The neutron energy spectrum consisted of the peak and continuum parts and the peak intensity was 0.9-1.1 $$times$$ 10$$^{10}$$ neutrons/sr/$$mu$$C. The ratio of peak intensity of the spectrum to the total intensity was between 0.38 and 0.48. To consider the correction required to derive a response in the peak region from the measured total response for neutron monitors, we proposed the subtraction method using energy spectra between 0$$^{circ}$$ and 25$$^{circ}$$. The normalizing factor k against the 25$$^{circ}$$ neutron fluence that equalizes the 0$$^{circ}$$ neutron fluence in the continuum region was from 0.74 to 1.02. With our previous results, we have obtained data for characterization of monoenergetic neutron field for the $$^{7}$$Li(p,n) reaction with 80$$sim$$389 MeV protons at the RCNP cyclotron facility.

Journal Articles

One-dimensional analysis of ECRH-assisted plasma start-up in JT-60SA

Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Kobayashi, Shinji*; Ide, Shunsuke; Isayama, Akihiko; Kajiwara, Ken

Fusion Science and Technology, 67(4), p.693 - 704, 2015/05

 Times Cited Count:10 Percentile:64.82(Nuclear Science & Technology)

no abstracts in English

Journal Articles

Characterization of quasi-monoenergetic neutron source using 137, 200, 246 and 389 MeV $$^{7}$$Li(p,n) reactions

Iwamoto, Yosuke; Hagiwara, Masayuki*; Iwase, Hiroshi*; Yashima, Hiroshi*; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Pioch, C.*; Mares, V.*; Shima, Tatsushi*; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.657 - 660, 2014/04

The authors measured the neutron energy spectra of the proton incident reaction on the lithium target with 137, 200, 246 and 389 MeV protons at several angles (0$$^{circ}$$, 2.5$$^{circ}$$, 5$$^{circ}$$, 10$$^{circ}$$, 15$$^{circ}$$, 20$$^{circ}$$, 25$$^{circ}$$ and 30$$^{circ}$$), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. For the neutron energy spectrum at 0$$^{circ}$$, the ratio of the peak neutron intensity to the total one varied between 0.4 and 0.5 depending on the incident energy. In order to consider the correction required to derive the response in the peak region from the measured total response for high-energy neutron detectors, the authors showed the subtractions of H*(10) obtained at larger angles from the 0$$^{circ}$$ data in the continuum part. It was found that subtracting the dose equivalent at about 22$$^{circ}$$ from the 0$$^{circ}$$ data reduces the continuum component most efficiency.

Journal Articles

Measurement of neutron energy spectra behind shields for quasi-monoenergetic neutrons generated by 246-MeV and 389-MeV protons using a Bonner sphere spectrometer

Matsumoto, Tetsuro*; Masuda, Akihiko*; Nishiyama, Jun*; Harano, Hideki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Yashima, Hiroshi*; Nakane, Yoshihiro; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.332 - 336, 2014/04

Recently, many high-energy accelerators are used for various fields. Shielding data for high-energy neutrons are therefore very important from the point of view of radiation protection in high energy accelerator facilities. However, the shielding experimental data for high energy neutrons above 100 MeV are very poor both in quality and in quantity. In this study, neutron penetration spectral fluence and ambient dose through iron and concrete shields were measured with a Bonner sphere spectrometer (BSS). Quasi-monoenergetic neutrons were produced by the $$^{7}$$Li(p,xn) reaction by bombarding a 1-cm thick Li target with 246-MeV and 389-MeV protons in the Research Center for Nuclear Physics (RCNP) of the Osaka University. Shielding materials are iron blocks with a thickness from 10 cm to 100 cm and concrete blocks with a thickness from 25 cm to 300 cm.

Journal Articles

Shielding benchmark experiment using hundreds of MeV quasi-monoenergetic neutron source by a large organic scintillator

Hagiwara, Masayuki*; Iwase, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Matsumoto, Tetsuro*; Masuda, Akihiko*; Yashima, Hiroshi*; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.327 - 331, 2014/04

We have developed several hundreds of MeV p-$$^{7}$$Li quasi-monoenergetic neutron fields in the Research Center for Nuclear Physics (RCNP), Osaka University, Japan. In this study, we extended the measurements to higher energy with a p-$$^{7}$$Li quasi-monoenergetic neutron source, which was produced from a 1.0-cm-thick lithium target bombarded with 246 and 389 MeV protons, using a larger NE213 scintillator of 25.4-cm in diameter and 25.4-cm in thickness. The large NE213 have good energy resolution for high energy neutrons, because it can stop recoil protons up to 180 MeV. The measured data are compared with the Monte-Carlo codes (PHITS with JENDL-HE data library) in the energy spectra, time spectra and the attenuation length of the peak neutrons. This comparison shows good agreement between experiments and calculations. The attenuation length estimated from the well-fitted curves with single exponential form will be useful for the practical shielding design of high energy accelerator facilities.

Journal Articles

Response measurement of various neutron dose equivalent monitors in 134-387 MeV neutron fields

Nakane, Yoshihiro; Hagiwara, Masayuki*; Iwamoto, Yosuke; Iwase, Hiroshi*; Satoh, Daiki; Sato, Tatsuhiko; Yashima, Hiroshi*; Matsumoto, Tetsuro*; Masuda, Akihiko*; Nunomiya, Tomoya*; et al.

Progress in Nuclear Science and Technology (Internet), 4, p.704 - 708, 2014/04

no abstracts in English

Journal Articles

Measurements and Monte Carlo calculations of forward-angle secondary-neutron-production cross-sections for 137 and 200 MeV proton-induced reactions in carbon

Iwamoto, Yosuke; Hagiwara, Masayuki*; Matsumoto, Tetsuro*; Masuda, Akihiko*; Iwase, Hiroshi*; Yashima, Hiroshi*; Shima, Tatsushi*; Tamii, Atsushi*; Nakamura, Takashi*

Nuclear Instruments and Methods in Physics Research A, 690, p.10 - 16, 2012/10

 Times Cited Count:4 Percentile:32.06(Instruments & Instrumentation)

Secondary neutron-production double-differential cross sections (DDXs) have been measured from interactions of 137 MeV and 200 MeV protons in a natural carbon target. The data were measured between 0$$^{circ}$$ and 25$$^{circ}$$ in the laboratory. Benchmark calculations were carried out with the PHITS code using the evaluated nuclear data files of JENDL/HE-2007 and ENDF/B-VII, and the theoretical models of Bertini-GEM and ISOBAR-GEM. For the 137 MeV proton incidence, calculations using JENDL/HE-2007 generally reproduced the shape and the amount of experimental spectra well including the ground state of the $$^{12}$$N state produced by the $$^{12}$$C(p,n)$$^{12}$$N reaction. ISOBAR predicts the nucleon emission to the forward angles qualitatively better than the Bertini model and JENDL/HE-2007. These experimental data will be useful to evaluate the carbon data and as benchmark data for investigating the validity of the Monte Carlo simulation for the shielding design of accelerator facilities.

Journal Articles

Analysis of ECRH pre-ionization for plasma start-up in JT-60SA

Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Kinjo, Ryota*; Ide, Shunsuke; Isayama, Akihiko

Plasma and Fusion Research (Internet), 7(Sp.1), p.2403104_1 - 2403104_5, 2012/07

no abstracts in English

Journal Articles

Response measurement of a Bonner sphere spectrometer for high-energy neutrons

Masuda, Akihiko*; Matsumoto, Tetsuro*; Harano, Hideki*; Nishiyama, Jun*; Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Nakamura, Takashi*; et al.

IEEE Transactions on Nuclear Science, 59(1), p.161 - 166, 2012/02

 Times Cited Count:11 Percentile:66.72(Engineering, Electrical & Electronic)

In this study, responses of Bonner sphere spectrometer (BSS) for 245 and 388 MeV neutrons was measured at RCNP, Osaka University. The neutrons are generated in the $$^{7}$$Li(p,n) reaction and its spectra consist of a high-energy peak and a continuum down to the low energy. Therefore, the observed counts of BSS caused by the continuum need to be subtracted. Adjusting a Li target angle and a collimator position, 0 deg and 30 deg component of generated neutron are available. While the 0 deg component contains both the peak and the continuum, the 30 deg component is considered to contain only the continuum. Therefore, the response of the peak is obtained. The spectra were measured using the time-of-flight (TOF) method with a NE213 scintillator.

Journal Articles

Structural and valence changes of europium hydride induced by application of high-pressure H$$_{2}$$

Matsuoka, Takahiro*; Fujihisa, Hiroshi*; Hirao, Naohisa*; Oishi, Yasuo*; Mitsui, Takaya; Masuda, Ryo; Seto, Makoto*; Yoda, Yoshitaka*; Shimizu, Katsuya*; Machida, Akihiko; et al.

Physical Review Letters, 107(2), p.025501_1 - 025501_4, 2011/07

 Times Cited Count:27 Percentile:77.69(Physics, Multidisciplinary)

Europium-hydride EuH$$_{x}$$ exposed to high-pressure H$$_{2}$$ conditions has been found to exhibit structural and valence changes, $$Pnma$$ ($$x$$=2, divalent) $$rightarrow$$ $$P$$63/$$mmc$$ ($$x$$=2, 7.2-8.7 GPa) $$rightarrow$$ $$I$$4/$$m$$ ($$x$$$$>$$2, 8.7-9.7 GPa) $$rightarrow$$ $$I$$4/$$mmm$$ ($$x$$$$>$$2, 9.7 GPa-, trivalent). Having trivalent character and distorted cubic fcc structure, the $$I$$4/$$mmm$$ structure is the $$beta$$-phase which has been commonly observed for other rare-earth metal hydrides. Our study clearly demonstrates that EuH$$_{x}$$ is no longer an "irregular" member of the rare earth metal hydrides.

Journal Articles

Characterisation of quadi-monoenergetic neutron energy spectra using $$^{7}$$Li(p,n) reactions at 246-389 MeV

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Proceedings of 10th Meeting of the Task Force on Shielding Aspects of Accelerators, Targets and Irradiation Facilities (SATIF-10), p.53 - 61, 2011/03

The neutron energy spectra penetrating 10 to 100 cm thick iron and 25 to 200 cm thick concrete shields have been measured using 138, 243 and 387 MeV quasi-monoenergetic neutron sources at the Research Center for Nuclear Physics (RCNP) facility, Osaka University. The source neutrons were produced from a 1 cm thick lithium target bombarded with 140, 245 and 388 MeV protons. Two types of NE213 liquid organic scintillators and Bonner ball neutron spectrometers were used for the neutron energy spectrum measurement. The TOF and unfolding methods were applied to estimate the energy spectra behind the shield in the peak energy region and continuous energy region, respectively. We have also measured the neutron energy spectra and angular distribution of the source neutron above 1 MeV in the angular range from 0$$^{circ}$$ to 30$$^{circ}$$ with the TOF method. All measured data were compared with the PHITS Monte Carlo calculations.

Journal Articles

Quasi-monoenergetic neutron energy spectra for 246 and 389 MeV $$^{7}$$Li(p,n) reactions at angles from 0$$^{circ}$$ to 30$$^{circ}$$

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

Nuclear Instruments and Methods in Physics Research A, 629(1), p.43 - 49, 2011/02

 Times Cited Count:21 Percentile:82.84(Instruments & Instrumentation)

The authors measured the neutron energy spectra of a quasi-monoenergetic $$^{7}$$Li(p,n) neutron source with 246 and 389 MeV protons set at seven angles (0$$^{circ}$$, 2.5$$^{circ}$$, 5$$^{circ}$$, 10$$^{circ}$$, 15$$^{circ}$$, 20$$^{circ}$$ and 30$$^{circ}$$), using a time-of-flight (TOF) method employing organic scintillators NE213 at the Research Center for Nuclear Physics (RCNP) of Osaka University. The energy spectra of the source neutrons were precisely deduced down to 2 MeV at 0$$^{circ}$$ and 10 MeV at other angles. The cross sections of the peak neutron production reaction at 0$$^{circ}$$ were on the 35-40 mb line of other experimental data, and the peak neutron angular distribution agreed well with the Taddeucci formula. Neutron energy spectra below 100 MeV at all angles were comparable, but the shapes of the continuum above 150 MeV changed considerably with the angle.

Oral presentation

Theoretical analysis of plasma initiation using ECRH in JT-60SA

Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Ide, Shunsuke; Isayama, Akihiko

no journal, , 

no abstracts in English

Oral presentation

Characterization of quasi-monoenergetic neutron energy spectra using the $$^{7}$$Li(p,n) reactions in the 245 and 388 MeV

Iwamoto, Yosuke; Hagiwara, Masayuki*; Satoh, Daiki; Iwase, Hiroshi*; Yashima, Hiroshi*; Itoga, Toshiro*; Sato, Tatsuhiko; Nakane, Yoshihiro; Nakashima, Hiroshi; Sakamoto, Yukio; et al.

no journal, , 

We have measured mono-energetic neutron energy spectra for the $$^{7}$$Li(p,n) reaction in the energy region above 2 MeV using the time-of-flight method at RCNP, Osaka University. Neutron detector were NE213 organic liquid scintillators (5.08 cm, 12.7 cm, and 25.4 cm diameter and thickness). Detection angles were 0, 2.5, 5, 10, 15, 20, 25, and 30 degrees. As spectra consist of a high-energy peak and a continuum down to the low energy, the observed data caused by the continuum was subtracted to obtain the peak neutron cross sections. While the 0 deg component contains both the peak and the continuum, the 10-30 deg component is considered to contain mainly the continuum. The angular distribution of the peak neutron cross section agreed with the Taddeucci formula.

Oral presentation

One-dimensional analysis of ECRH preionization for plasma production in JT-60SA

Hada, Kazuyoshi*; Nagasaki, Kazunobu*; Masuda, Kai*; Kinjo, Ryota*; Ide, Shunsuke; Isayama, Akihiko

no journal, , 

no abstracts in English

35 (Records 1-20 displayed on this page)