| Budget Amount *help |
¥1,300,000 (Direct Cost: ¥1,300,000)
Fiscal Year 1986: ¥500,000 (Direct Cost: ¥500,000)
Fiscal Year 1985: ¥800,000 (Direct Cost: ¥800,000)
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| Research Abstract |
Although the basic physical principles governing transport of photons were known many decades previously, it was only through the use of computers that these principles could by applied to photon shielding with high accuracy. Satisfactory computational methods for analysing radiation transport is still developing. The purpose of this study is to show the state of present art making photon transport calculations for low Z materials and for low source energies.
These are two representative discrete ordinates codes, the PALLAS and ANISN, using different approximating techniques, which are designed to solve the deep penetration problem with techniques for handling an isotropic scattering. As a typical example, buildup factors and energy spectra for beryllium were calculated by two calculation codes, and were compared with those of the point Monte Carlo method code, EGS4. These calculated results were in a good agreement up to 10 mfp with one another. The results of the PALLAS and ANISN calculations were within 40 % up to 40 mfp.
Gamma ray transport in iron-or lead-tissue system was calculated with the PALLAS code. Buildup factors and energy spectra at the interface and in tissue show significantly different from those of infinite medium.
An American Nuclear Society Standards Committee Working Group, identified as ANS-6.4.3, is developing a set of evaluated gamma-ray isotropic point-source buildup factors and attenuation coefficients for a standard reference data base. In June 1985, the head investigator was asked to become a member of Working Group ANS-6.4.3. Above results are expected to be adopted as a part of standard reference data.
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