NEA-1727 BULK-I.

1. NAME OR DESIGNATION OF PROGRAM:  BULK-I.

3. DESCRIPTION OF PROGRAM OR FUNCTION

BULK-I is a tool for calculating neutron and photon effective dose rates after penetrating through concrete or two layers with iron and concrete in a medium energy range proton accelerator facility (energies from 50 to 500 MeV)..This tool is also capable of radiation shielding calculations considering various proton energies and proton beam directions like proton beam treatment facilities.

4. METHODS

In BULK I  a simple formula adopted for not only the equilibrium region but also for the build-up region is proposed, and the parameters for concrete or two layers with iron and concrete are numerically obtained with the Monte Carlo code MCNPX. The geometry used in the tool consists of a target (radiation source) placed at the origin in the rectangular room surrounded by six concrete walls. The target is assumed to be thick iron as a typical component of the proton accelerator. Protons with various energies and directions are taken into account in the dose rate calculation based on the gantry employed in a proton beam treatment facility. The dose rates at estimator points are calculated considering the emission angle relative to each proton beam direction, and incident angle relative to X, Y or Z axis, which are automatically calculated by the tool. The distance from the target to the inner surface, and the thickness of each concrete wall are given by users. The fixed type and the beam direction dependent type of iron shields can be dealt with. For the former, the barrier thickness in iron as measured radiation path through the shield is given for each estimator, and for the latter the thickness and solid angle relative to the beam direction are given. Estimators are set at any positions in and outside the concrete walls. The attenuation in the air is ignored.

5. RESTRICTIONS ON THE COMPLEXITY OF THE PROBLEM

The application limits of the tool are as follows.
1) Proton energy: 50 - 500MeV
2) Emission angle relative to beam direction: 0-180 degrees (12 bins)
3) Barrier thickness in concrete: 100 - 735 g/cm2 (including build-up region)
4) Barrier thickness in iron: 0, 25, 50 and 70 cm (density 7.83 g/cm3)
The tool is not applicable for radiation streaming problems like a maze and a duct, and skyshine problems, and the DUCT-III code and SHINE-III code are recommended, respectively.

8. RELATED OR AUXILIARY PROGRAMS:  DUCT-III and SHINE-III.

- R. Tayama, K. Hayashi and H. Hirayama:
BULK-I Radiation Shielding Tool for Proton Accelerator Facilities
KEK Internal 2004-1 June 2004 A/R

This version was tested at the NEA Databank on a PC with 3GHz INTEL Pentium 4.

This version was tested at the NEA Databank under the WINDOWS XP Professional operating system.

15. NAME AND ESTABLISHMENT OF AUTHORS

Ryuichi TAYAMA and Katsumi HAYASHI
Hitachi, Ltd. Power & Industrial Systems
Hideo HIRAYAMA
High Energy Accelerator Research Organization,
Applied Research Laboratory, Radiation Science Center
Japan

tool.xls   BULK-I spreadsheet
sample input
sample output data