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Journal Articles

Measurement of radioactive fragment production excitation functions of lead by 400 MeV/u carbon ions

Ogawa, Tatsuhiko; Morev, M.*; Iimoto, Takeshi*; Kosako, Toshiso*

Progress in Nuclear Science and Technology (Internet), 4, p.574 - 577, 2014/04

Depth distributions of radioactive fragments in a thick lead target exposed to 400 MeV/u carbon ions were measured to obtain isotopic production cross-sections of $$^{Nat}$$Pb(C,x) X reactions as excitation functions. The procedure of this experiment was validated by comparing the obtained data with the available thin target experimental data. Energy and mass dependences of the obtained cross-sections give insight into the reaction mechanism and will be useful for radiation transport code benchmarking.

Journal Articles

Measurement of radioactive fragment production excitation functions of lead by 400 MeV/u carbon ions

Ogawa, Tatsuhiko; Morev, M. N.*; Kosako, Toshiso*

Transactions of the American Nuclear Society, 109(2, Part2), p.1253 - 1255, 2013/11

Depth distributions of radioactive fragments in a thick lead target exposed to 400 MeV/u carbon ions were measured to obtain isotopic production cross-sections of $$^{Nat}$$Pb($$^{12}$$C,x)X (X=$$^{46}$$Sc, $$^{48}$$V, $$^{54}$$Mn, $$^{56}$$Co, $$^{58}$$Co, $$^{59}$$Fe, $$^{75}$$Se, $$^{83}$$Rb, $$^{85}$$Sr, $$^{113}$$Sn, $$^{121}$$Te, $$^{127}$$Xe, $$^{133}$$Ba, $$^{139}$$Ce, $$^{143}$$Pm, $$^{144}$$Pm, $$^{146}$$Gd, $$^{148}$$Eu, $$^{149}$$Gd, $$^{172}$$Hf and $$^{175}$$Hf) reactions as excitation functions. The obtained fragment distributions were converted to excitation functions of fragmentation cross-sections by the modified stacked-foil method. This conversion procedure was validated by comparing the obtained data with the available thin target experimental data. The obtained cross-sections were in good agreement with the previously published results. Comparison of the obtained cross-sections and the simulation by PHITS showed that PHITS underestimates fragments lighter than 90 amu by factor of about 10 whereas the fragments heavier than 110 amu were predicted within a factor of 3. Energy and mass dependences of the obtained cross-sections give insight into the reaction mechanism and will be useful for radiation transport code benchmarking. Furthermore, this study clarified that excitation functions of fragmentation reactions induced by heavy ions can be obtained by applying the method adopted in this study.

Journal Articles

Management of cosmic radiation exposure for aircraft crew in Japan

Yasuda, Hiroshi*; Sato, Tatsuhiko; Yonehara, Hidenori*; Kosako, Toshiso*; Fujitaka, Kazunobu*; Sasaki, Yasuhito*

Radiation Protection Dosimetry, 146(1-3), p.123 - 125, 2011/07

 Times Cited Count:13 Percentile:71.79(Environmental Sciences)

The National Institute of Radiological Sciences (NIRS) has helped the airlines companies to follow the guideline, particularly for the calculation of aviation route doses. The presentation will show the annual individual doses of aircraft crew calculated for the 2007 fiscal year.

Journal Articles

Dose evaluation from multiple detector outputs using convex optimisation

Hashimoto, Makoto; Iimoto, Takeshi*; Kosako, Toshiso*

Radiation Protection Dosimetry, 146(1-3), p.65 - 68, 2011/07

 Times Cited Count:0 Percentile:0.01(Environmental Sciences)

A dose evaluation using multiple radiation detector outputs can be improved by the convex optimisation. It enables flexible dose evaluation corresponding to the radiation field. The neutron ambient dose equivalent is evaluated using a mixed-gas proportional counter. The reliability of evaluated dose values are comparable with current dosimeter. An application to neutron individual dose equivalent measurement is also investigated. The combination of dosimeters with high orthogonality of response characteristics tends to show good suitability for dose evaluation.

Journal Articles

Applicability of convex hull in multiple detector response space for neutron dose measurements

Hashimoto, Makoto; Iimoto, Takeshi*; Kosako, Toshiso*

Radiation Protection Dosimetry, 136(1), p.1 - 10, 2009/07

 Times Cited Count:1 Percentile:10.95(Environmental Sciences)

A novel neutron dose measurement method which flexibly responds to variations of neutron field is being developed in JAEA. This is an implementation of the multi-detector method (first introduced in early 1970s) for neutron dose evaluation using convex hull in the response space defined for multiple detectors. The convex hull provides range of possible neutron dose corresponding to the incident neutron spectrum. Feasibility of the method was studied using simulated response of mixed-gas proportional counter. Monochromatic neutrons are shown to be fundamentally suitable for mapping the convex hull. The convex hull can be further reduced taking into consideration ${it a priori}$ information about physically possible incident neutron spectra, for example, theoretically derived moderated neutron spectra originated from a fission neutron source.

Journal Articles

Dose evaluation with closed space in vector space composed of radiation detector outputs

Hashimoto, Makoto; Iimoto, Takeshi*; Kosako, Toshiso*

Proceedings of International Symposium commemorating the First Anniversary of the Foundation of GoNERI "Key to the Future; Energy Security and Nuclear Education & Research", p.247 - 252, 2008/10

Neutron dose evaluation method which flexibly respond to an alteration of neutron field is developing. The mulitidetector method is introduced. The method uses a convex hull in a topological vector space composed of the ratio of multi detector outputs and objective quantities. The convex hull provides range of possible conversion factor to obtain objective quantity based on the circumstance condition. The convex hull is sophisticated with elemental neutron spectra group of respective neutron field. Mixed gas proportional counter is applied to validate the effectively of the dose evaluation method with a convex hull.

Journal Articles

Development of a wide-range paired scintillator with optical fiber neutron monitor for BNCT irradiation field study

Ishikawa, Masayori*; Kumada, Hiroaki; Yamamoto, Kazuyoshi; Kaneko, Junichi*; Bengua, G.*; Unesaki, Hironobu*; Sakurai, Yoshinori*; Tanaka, Kenichi*; Kosako, Toshiso*

Nuclear Instruments and Methods in Physics Research A, 551(2-3), p.448 - 457, 2005/10

 Times Cited Count:10 Percentile:60.27(Instruments & Instrumentation)

A wide range thermal neutron detector was developed based on the Scintillator with Optical Fiber (SOF) detector which has been previously used for thermal neutron monitoring during boron neutron capture therapy irradiation. With this new detector system we intended to address the issues of real-time thermal neutron flux measurement and the simultaneous measurement of a wide range of thermal neutron flux in a BNCT irradiation field which were difficult to implement with the gold wire activation method. A good agreement between the thermal neutron flux measured by the gold wire activation method and the paired SOF detector system was observed. However, measurements which would normally take a few days to perform with the gold wire activation method were obtained in just about 15 min using the SOF detector system. We also confirmed the dynamic range of linearity for the SOF detector system to be in the order of magnitude of 1e-4.

JAEA Reports

An Investigation of methods for neutron dose measurement in high temperature irradiation fields

Kosako, Toshiso*; Sugiura, Nobuyuki*; Kudo, Kazuhiko*; Mori, Chizuo*; Iimoto, Takeshi*; Shikama, Tatsuo*; Katagiri, Masaki; Hayashi, Kimio; Aihara, Jun; Shibata, Taiju; et al.

JAERI-Review 2000-017, 78 Pages, 2000/10

JAERI-Review-2000-017.pdf:4.62MB

no abstracts in English

Journal Articles

Future scope of applying radiation and radio isotopes to physical science and engineering

Abe, Fumitoshi*; Ota, Shizuko*; Kosako, Toshiso*; Tanaka, Ryuichi; Tominaga, Hiroshi*; Yamamoto, Masago*; Ujihira, Yusuke*

Isotope News, (501), p.16 - 26, 1996/02

no abstracts in English

Journal Articles

Treatment of radioactive waste in institutes

Kosako, Toshiso*; *; *;

Kenkyu Bunya-niokeru housyasei Haikibutu No Toriatukai, 0, p.27 - 31, 1994/03

no abstracts in English

Journal Articles

Radiation protection in a large fusion experiments

Seki, Yasushi; Kosako, Toshiso*

Nihon Genshiryoku Gakkai-Shi, 32(1), p.33 - 36, 1990/01

no abstracts in English

Journal Articles

Annotated bibliography and discussion of gamma-ray buildup fuctors

Tanaka, Shunichi; *; Hirayama, Hideo*; Ban, Shuichi*; Nakamura, Takashi*; Kosako, Toshiso*; *; *; *; Kawai, Masayoshi*; et al.

Applied Radiation and Isotopes, 39(2), p.241 - 252, 1988/00

no abstracts in English

Journal Articles

Current status and future scope of gamma-ray buildup factor

Tanaka, Shunichi; Sakamoto, Yukio; Tanaka, Susumu; *; Hirayama, Hideo*; Ban, Shuichi*; Kosako, Toshiso*; *; *; Nakamura, Takashi*; et al.

Nihon Genshiryoku Gakkai-Shi, 30(5), p.385 - 393, 1988/00

no abstracts in English

Journal Articles

Nonreactor nuclear facilities; Standards and criteria guide

Kosako, Toshiso*; *; *; Kawata, Tomio*; *; *; *; Yamaki, J.;

Genshiro Igai No Genshiryoku Shisetsu No Kijun To Shishin (Beikoku), 404 Pages, 1986/00

no abstracts in English

Journal Articles

Health and safety excecutive.Safety assessment principles for nuclear chemical plant.

Kosako, Toshiso*; *; *; *; *; *; Yamaki, J.;

Genshiryoku Kagaku Puranto Ni Taisuru Anzen Shinsa Shishin (Eikoku), 75 Pages, 1986/00

no abstracts in English

JAEA Reports

A Helium-3 proportional counter technique for estimating fast and intermediate neutrons

Kosako, Toshiso*; Nakazawa, Masaharu*; Wakabayashi, Hiroaki*; Sekiguchi, Akira*

PNC TJ260 78-06, 97 Pages, 1976/11

PNC-TJ260-78-06.pdf:4.58MB

$$^{3}$$He proportional counter was employed to determine the fast and intermediateneutron spectra of wide energy region. The mixed gas ($$^{3}$$He, Kr) type counterresponse and the spectrum unfolding code were prepared and applied to some neutronfields. The counter response calculation was performed by using the Monte Carlocode,paying regards to dealing of the particle range calculation of the mixed gas.An experiment was carried out by using the van de Graaff accelerator to check theresponse function. The spectrum unfolding code was prepared so that it mayhave the function of automatic evaluation of the higher energy spectum's effectto the pulse hight distribution of the lower energy region. The neutron spectraof the various neutron fields were measured and compared with the calculations suchas the discrete ordinate Sn calculations. It became clear that the techniquedeveloped here can be applied to the practical use in the neutron energy rangefrom about 150 KeV to 5 MeV.

Oral presentation

Study on neural network application for bonner sphere neutron spectrometry

Hashimoto, Makoto; Sohn, S.-K.*; Iimoto, Takeshi*; Kosako, Toshiso*

no journal, , 

While unfolding calculation is widely applied for the neutron spectrum evaluation with multi moderator method, such experiments can configure neural network for neutron spectrum evaluation and it makes quick to evaluate the neutron spectrum. Conformation of the neural network and effects of some condition to the network will be discussed.

Oral presentation

Discussion about the application of neural network technique for neutron dosimetory

Hashimoto, Makoto; Sohn, S.-K.*; Iimoto, Takeshi*; Kosako, Toshiso*

no journal, , 

Application of neural network technique for neutron spectrometry with multi-moderator neutron spectrometer is discussed. It is confirmed that the convergent of neural network estimation is good in a case of high orthogonarity in responses of multi-moderated detectors.

Oral presentation

Dose evaluation with closed space in vector space composed of radiation detector outputs

Hashimoto, Makoto; Sohn, S.-K.*; Iimoto, Takeshi*; Kosako, Toshiso*

no journal, , 

It is known that the ratios of multiple detectors outputs and objective values compose closed convex in vector space forming with these ratios in the case of optimum obcective value evaluation, such as dose evaluation, with multiple radiation detectors. Neutron dose evaluation method with this method is discussed. A neutron detector with high sensitivity for thermal neutrons and fast neutrons combined was applied for dose evaluation experiment with this method. The response of the detector was simulated by calculation and experimentally validated with mono-energy neutron and RI. A vector space with tis detector was calculated. It is confirmed that the simulated outputs of detectors with various types of neutron field and experimental outputs plotted in this vector space are arranged in closed convex.

Oral presentation

Radionuclide migration and related dose around a uranium mining site

Sato, Kazuhiko; Koga, Osamu; Tokizawa, Takayuki; Iimoto, Takeshi*; Kosako, Toshiso*

no journal, , 

24 (Records 1-20 displayed on this page)