Shielding Analysis of Nuclear Data Measurement Facility Using EGS4 and MCNP4 Codes

Abstract

The electron accelerator facility generating high-energy particle for nuclear data measurements has a probability of radiation emission at all times, and thus, the shielding analysis for the facility should be performed. In this work, two Monte Carlo codes, EGS4 and MCNP4B, were employed for the accurate calculations of radiation source term and ambient dose at the working areas, EGS4 code was used in the calculation of neutron and photon sources from the accelerator beam line and the beam target. The ambient dose at the working areas was calculated by MCNP4B code using neutron and photon source terms calculated from the EGS4 runs, The results showed that the ambient dose at the working areas was much higher than the design limit of PohangAccelerator Laboratory, 5 µSv/hr, and thus, it is recommended that the additional effective shields, lead shield of 14 cm thick at the LINAC room and 11 cm thick at the target room, should to be installed for ensuring radiation safety of the nuclear data measurement facility.

Study on the radiation problem caused by electron beam loss in accelerator tubes

“…It can be seen that the angle between the lost electrons and the beam axis is small, which agrees with the Ref. [2].…”

“…Electron linacs are widely used in facilities of radiotherapy, nondestructive inspection, container inspection system at the Customs, industrial computed tomography (ICT), etc. For a low-energy linac during its normal run, the electron beam loss takes place in the accelerator tube, in the bending magnet, in the attachment of components [1] , in the electron transportation tubes [2,3] , etc. In common RF accelerators, among the total electrons emitted by the electron gun, only electrons whose phases are within a particular interval can be accelerated stably.…”