Comparison of MCNP and INSREC-HEP codes for radiation evaluation at the maze entrance of treatment room

Generally, in the treatment room using the high energy Linac, the dose at the maze entrance caused by photoneutron except photon have an influence on the patients and workers. Because of this fact, the dose evaluation necessity for the photoneutron is raised. So we developed the photoneutron dose calculation program, named as 'IMED-HEP'. This program has been developed by using a experimental formula based on the Kersy theory and as the form of the windows-based program for offering the convenience to user. This formula used in this program has properties that the photoneutron dose at the maze entrance is known as being changed by the neutron particle transport length, the width/height of the maze, and neutron-source term location. To evaluate the developed program validation, the dose result calculated by this program was compared with that of the reliable MCNP code. As a comparison results, the maximum error for dose at the maze entrance was about 9%. So, the developed IMED-HEP program could be concluded as this program have a reliable calculation capability for photoneutron dose. (authors)