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Tsuda, Shuichi; Nakane, Yoshihiro; Yamaguchi, Yasuhiro
Radiation Protection Dosimetry, 126(1-4), p.174 - 177, 2007/08
Times Cited Count：6 Percentile：42.5(Environmental Sciences)no abstracts in English
Takahashi, Fumiaki; Endo, Akira
Radiation Protection Dosimetry, 126(1-4), p.595 - 599, 2007/08
Times Cited Count：2 Percentile：18.73(Environmental Sciences)no abstracts in English
Satoh, Daiki; Sato, Tatsuhiko; Endo, Akira; Matsufuji, Naruhiro*; Takada, Masashi*
Radiation Protection Dosimetry, 126(1-4), p.555 - 558, 2007/08
Times Cited Count：2 Percentile：18.73(Environmental Sciences)In order to assess the neutron dose with DARWIN, a set of reliable response functions for neutron is required. Although the response function for neutron has been already determined below 100 MeV, the evaluation method is not established for high-energy neutrons. This is a reason to restrict the applicable energy of DARWIN at 100 MeV. To extend the applicable energy, we developed SCINFUL-QMD code which is capable of calculating the response function up to a few GeV. To verify the SCINFUL-QMD, response functions above 100 MeV have been measured at the HIMAC of National institute of Radiological Sciences. Neutrons were produced by bombardment 800 MeV/u Si and 400 MeV/u C ions with a graphite target. The experimental results showed a good agreement with predictions of SCINFUL-QMD. The G-function was evaluated up to 1 GeV based on the calculation of SCINFUL-QMD.
Sato, Tatsuhiko; Satoh, Daiki; Endo, Akira; Yamaguchi, Yasuhiro
Radiation Protection Dosimetry, 126(1-4), p.501 - 505, 2007/08
Times Cited Count：4 Percentile：31.41(Environmental Sciences)A new inventive radiation dose monitor, designated as DARWIN (Dose monitoring system Applicable to various Radiations with WIde energy raNges), has been developed for real-time monitoring of doses in workspaces and surrounding environments of high energy accelerator facilities. DARWIN satisfies the following features: (1) capable of monitoring doses from neutrons, photons and muons with wide energy ranges - from thermal energy to 1 GeV, 150 keV to 100 MeV, and 1 MeV to 100 GeV, respectively, (2) high sensitivity and precision - more than 10 times as sensitive as conventional moderator-based survey instruments for neutrons, (3) easy to operate with a simple user-interface, and (4) light weighted for movability. The details of the features will be described at the presentation, together with the results of the calibrations performed in several accelerator facilities.
Sc(p,n)Ti reaction at JAEATanimura, Yoshihiko; Saegusa, Jun; Shikaze, Yoshiaki; Tsutsumi, Masahiro; Shimizu, Shigeru; Yoshizawa, Michio
Radiation Protection Dosimetry, 126(1-4), p.8 - 12, 2007/08
Times Cited Count：12 Percentile：63.69(Environmental Sciences)no abstracts in English
O-moderated 
Cf sourceKowatari, Munehiko; Fujii, Katsutoshi; Takahashi, Masa; Yoshizawa, Michio; Shimizu, Shigeru; Kawasaki, Katsuya; Yamaguchi, Yasuhiro
Radiation Protection Dosimetry, 126(1-4), p.138 - 144, 2007/08
Times Cited Count：5 Percentile：37.19(Environmental Sciences)The facility of the Radiation Standards (FRS) of the Japan Atomic Energy Agency was equipped with the reference neutron field by using DO moderated Cf neutron source (DO-Cf), with a 30cm diameter DO sphere. In order to determine the characteristics of the reference field within the ranges of calibration distance (75 to 200 cm from the center of the source to the calibration point) in detail, the authors performed the evaluation of the neutron spectra and neutron fluence rate at various distances from the DO moderated source assembly by computations using MCNP-4C and by experimental studies using Bonner Multi-sphere neutron Spectrometer (BMS). Due to the volume neutron source, it is difficult to measure the contribution of the scattered neutron component with the desirable accuracy by shadow-cone method. In this study, the net counting rate of each counter of BMS was corrected by estimating the ratio of the counting rate of each counter in condition of the experimental and the ideal arrangement by the Monte Carlo calculation. The spectra of the direct component were unfolded by using the corrected counting rate with SAND II code. The averaged dose conversion coefficients (h
(10) and h
(10)) and neutron dose rates (H(10) and H(10)) at various distance were estimated based on the measured spectra. The effectiveness of the correction was discussed by comparing the measured and calculated values. Additionally, the suitable distance for the calibration of personal dosimeter at FRS reference field was evaluated by the results.
Shikaze, Yoshiaki; Tanimura, Yoshihiko; Saegusa, Jun; Tsutsumi, Masahiro; Yamaguchi, Yasuhiro; Uchida, Yoshiaki*
Radiation Protection Dosimetry, 126(1-4), p.163 - 167, 2007/08
Times Cited Count：3 Percentile：25.51(Environmental Sciences)For neutron energy more than 20 MeV, the international standard of the calibration fields and techniques has not been established. Therefore, by using the quasi-monoenergetic neutron irradiation field of 40-90 MeV at TIARA of JAEA Takasaki, we are developing the calibration field. Here we evaluated the properties of the neutron field, where neutrons were produced in the nuclear reaction of the Li target with 45, 50 and 70 MeV protons. We investigated the neutron beam profile at different distance from the target by using the imaging plates with a polyethylene converter to measure the recoil protons produced in the converter. From the results, properties of the neutron beam profile were found as follows: (1) Irradiation field area was fixed geometrically by the distance from the target and the diameter of the collimator exit; (2) The beam intensity within the irradiation field was in inverse proportion to the square of the distance from the target. Also, we measured the peak energy and energy spectrum of neutron through TOF method by using organic liquid scintillation detector. Then we evaluated the energy spectra of the scattered neutrons at various positions outside the irradiation field through unfolding method. The FORIST unfolding code and the response of SCINFUL-QMD code were used here. From the neutron energy spectra obtained in the different method mentioned above, peak fluence for on-beam position was evaluated comparing with the results in previous evaluation of the neutron field at TIARA.
Tsujimura, Norio; Yoshida, Tadayoshi; Takada, Chie; Momose, Takumaro; Nunomiya, Tomoya*; Aoyama, Kei*
Radiation Protection Dosimetry, 126(1-4), p.261 - 264, 2007/08
Times Cited Count：0 Percentile：0.01(Environmental Sciences)The authors developed a new neutron measuring-instrument that was designed to measure neutron personal dose equivalent, 
(10). This detector is composed a central thermal neutron detector, a core-polyethylene moderator, a front-hemispherical polyethylene moderator and rear-hemispherical boron-contained polyethylene absorber. Dimensions of each part were determined so as to provide energy- and angular-responses close to energy- and angular-dependencies of neutron (10), based on the Monte Carlo calculations.
Tsujimura, Norio; Yoshida, Tadayoshi; Momose, Takumaro
Radiation Protection Dosimetry, 126(1-4), p.168 - 173, 2007/08
Times Cited Count：5 Percentile：37.19(Environmental Sciences)The authors developed a model calculating angular neutron fluence distributions for radionuclide neutron sources which are heavily encapsulated or surrounded with some source support structures such as a source holder and a source movement system. These structures cause a highly anisotropic neutron fluence distribution, and hence it should be properly corrected for calibration of neutron measuring instruments. The calculations were made for two types of widely used neutron sources, 
Am-Be and Cf, by a combination of the in-house code simulating 
Be(
,n) reactions and the Monte Carlo code MCNP4C. As a result, anisotropy factors in the direction perpendicular to the source capsule axis for bare neutron sources were evaluated to be 1.012, 1.030 and 1.035 for Cf in a standard Amersham X1 capsule, Am-Be in a X3 capsule and Am-Be in a X4 capsule, respectively. These values are in reasonable agreements with published data. In contrast, anisotropy factors for these neutron sources including support structures increased by approximately 10% due to scattering of neutrons.
Li(p,n)Be reaction in the energy range from 250 to 390 MeV at RCNPTaniguchi, Shingo*; Nakao, Noriaki*; Nakamura, Takashi*; Yashima, Hiroshi*; Iwamoto, Yosuke; Satoh, Daiki; Nakane, Yoshihiro; Nakashima, Hiroshi; Itoga, Toshio*; Tamii, Atsushi*; et al.
Radiation Protection Dosimetry, 126(1-4), p.23 - 27, 2007/08
Times Cited Count：14 Percentile：66.15(Environmental Sciences)A quasi-monoenergetic neutron field was developed using the reaction in the energy range from 250 to 390 MeV in the ring cyclotron facility at the Research Center for Nuclear Physics (RCNP), Osaka University. Neutrons were generated from a 10-mm thick Li target injected by 250, 350 and 392 MeV protons. The neutrons produced at 0 degree were extracted into the 100-m long TOF room through a 150-cm thick ironcollimator of 10 cm 
12 cm aperture, and were measured by a 12.7-cm diam. 12.7-cm long NE213 organic liquid scintillator. This neutron field is very useful since experimental data for high energy neutrons in this energy region are very scarce. It has already been used for a neutron shielding experiment.
