Revise of a basic data base for shielding design

*; Takemura, Morio*

JNC TJ9440 2000-005, 157 Pages, 2000/03

JNC-TJ9440-2000-005.pdf:3.7MB

With use of the two-dimensional discrete ordinates code DORT and the standard groupwise shielding design library JSSTDL produced from the latest evaluated nuclear data library JENDL-3.2, experimental analyses for the representative configurations in the Radial Shield Attenuation Experiment of the JASPER were performed. The results were compared with those obtained with use of traditional method DOT3.5/JSDJ2 for the previous JASPER experimetal analyses. In general, the change of the cross section library gives higher results and the change of the transport code gives lower results. Finally the new analysis method gives better agreement with the experimental results and also less deviations of calculational errors between various detectors. Experimental analyses for the thick concrete configulation in the Gap Streaming Experiment of the JASPER was also performed with the new analysis method, after solving the poor agreement found in last year with the original JASPER experimental analyses. The same tendency due to the library change was confirmed with the above mentioned analyses of the Radial Shield Attenuation Experiment. Compilation of the input data necessary for future reanalyses of important configurations in JASPER experiments were continued through the above-mentioned experimental analyses and related informations were added for repletion of the database preserved in a computer disk holding previously accumulated data. Input data descriptions were made for auxiliary routines needed for the experimental analyses and their sample data were compiled and stored in the database.

Contribution of isobaric analog resonance to (p,n) spectra at intermediate energies

Hashimoto, Shintaro; Sato, Tatsuhiko; Niita, Koji*

no journal, , 

Particle transport simulation codes such as PHITS have been used for calculation of radiation shielding in accelerator facilities. In PHITS, INCL describes proton-induced nuclear reactions at intermediate energies of several 100 MeV. Calculated results by the models can reproduce the neutron spectra very well. However, it was pointed out that the calculated results at forward angles underestimate the experimental data in the neutron spectra of lower energies than incident energies by several 10 MeV. In this study, we developed a resonance cross section model considering Isobaric Analog and Gamow Teller resonances on the basis of Evaluated Nuclear Structure Data File (ENSDF). By summing up the result of the model and that of INCL, PHITS can reproduce the experimental data of the proton-induced reaction on Lead targets very well. It is expected that PHITS with the new model gives high accurate results in the calculation of the radiation shielding.

Track-structure simulation mode of low energy electrons for nanoscale spatial resolution

Kai, Takeshi; Sato, Tatsuhiko

no journal, , 

When applying a general purpose particle transport simulation code such as PHITS to the study of biological body influence by radiation exposure, it is important to evaluate energy deposition (dose) for organ size, and to simulate precisely radiation interaction in DNA size (nanoscale) because low energy secondary electrons, which become an importance for chemical reaction process after energy deposition, have been included some unknown factors. To clear the problem, we developed track structure simulation mode to make behavior calculation of the low energy electron in arbitrary 3-D systems and various materials possible. Various application studies involved in microscopic radiation interaction such as DNA damage simulations will be expected using this simulation mode implemented below PHITS ver.2.93.

Development of track-structure simulation mode of ions in PHITS

Kai, Takeshi; Sato, Tatsuhiko; Liamsuwan, T.*; Nikjoo, H.*

no journal, , 

A general purpose particle transport simulation code, PHITS is expected to apply dose evaluation in macroscopic systems as well as radiation interaction investigation in nanoscale for study of interaction between radiations and materials. To clear the problem, we implemented track structure calculation codes into the PHITS. The codes make microscopic behavior as well as energy depositions (ionization and excitation) of the electrons, protons and carbon ions possible. The PHITS could evaluate radiation dose of cellar size. As this implementation, DNA damage predictions, which need radiation interaction in the molecular levels, will be expected using this track-structure simulation mode.

Electron track structure analysis by PHITS

Kai, Takeshi; Matsuya, Yusuke; Sato, Tatsuhiko

no journal, , 

A general purpose particle transport simulation code, PHITS is expected to apply dose evaluation in macroscopic systems as well as radiation interaction investigation in nanoscale for study of interaction between radiations and materials. To clear the problem, we developed track structure mode codes of the PHITS. We predicted yields of the DNA damage by the mode. We found that the mode could reproduce experimental results of the DNA damage yields by electron irradiation into the cells. The PHITS could evaluate radiation dose of cellar size. The track structure mode made the prediction of DNA damage yields possible.

Studies on the effective dose for public calculated by air dose rate

Endo, Yuya; Yamaguchi, Katsuhiko*; Takase, Tsugiko*; Uezu, Yasuhiro; Tsukada, Hirofumi*

no journal, , 

After the Fukushima Dai-ichi Nuclear Power Station accident, the Ministry of the Environment decided that the additional annual dose in a high exposure situation (less than 20 mSv/y) reduced to 1 mSv/y or less. The additional annual dose is calculated by ambient dose equivalent. However, the relationship among air kerma, ambient dose equivalent and effective dose seems to be identically by many people. In addition, conversion coefficients from air kerma and ambient dose equivalent to effective dose have been considered to change as time proceeds because the half-lives of Cs and Cs are different. Therefore, agricultural land in an evacuation zone was selected to evaluate relationship among them. Furthermore, the actual environment such as soil will be simulated by using a Monte Carlo radiation transport code PHITS. Finally, the relationship will be verified by comparing the results calculated by PHITS to ones obtained from actual environmental monitoring.

Development of track structure analysis mode

Kai, Takeshi

no journal, , 

A general purpose particle transport simulation code, PHITS is expected to apply dose evaluation in macroscopic systems as well as radiation interaction investigation in nanoscale for study of interaction between radiations and materials. To clear the problem, we developed track structure mode. The PHITS could evaluate radiation dose of cellar size. The track structure mode made the prediction of DNA damage yields possible. In this presentation, we will introduce the method for utilization of the track structure mode to get new users.