Calculation of Effective Doses for External Neutrons

Abstract

Monte Carlo calculations of the effective dose, on the basis of 1CRP Publication 60, were performed for external neutrons from thermal energy to 18.3 MeV for five irradiation geometries: AP, PA, RLAT, ROT and ISO. A unisex anthropomorphic phantom and the MORSE-CG code were used in conjunction with a nuclear data set based on the JENDL-3 library. The effective dose was found to be superior to the effective dose equivalent, the former quantity, for neutrons below about 1 MeV and inferior above this energy for all the geometries. The ambient dose equivalent based on the new Q-L relationship proposed in the Publication was found not necessarily to give a conservative estimate of the effective dose for the AP and PA geometries. The results obtained here were in good agreement with those calculated with a different computer code and a different nuclear data set.

KEYWORDS:

• Monte Carlo method
• effective doses
• external irradiation
• MeV range 10-100
• neutrons
• ICRP
• Publication 60
• JENDL-3
• effective dose equivalent
• ambient dose equivalent
• new Q-L relationship
• computer codes
• computer calculations
• comparative evaluations