Development and Characterization of a Neutron Personal Dose Equivalent Monitor

The authors developed a new neutron-measuring instrument that was designed to measure a neutron personal dose equivalent, Hp(10). This instrument is composed of a conventional moderator-based neutron dose equivalent meter and a neutron shield made of borated polyethylene which covers a backward hemisphere to adjust the angular dependence. The whole design was determined on the basis of MCNP calculations so as to have response characteristics which would generally match both the energy and angular dependencies of Hp(10). The verification experiments for energy and angular responses were done using monoenergetic neutrons produced by the accelerator and polyenergetic neutrons from the moderated 252 Cf source. Experiments showed that the new instrument has reasonably acceptable responses as a reference neutron dosemeter. The authors conclude that this new instrument will be a great help in assessing the reference values of neutron Hp(10) during field testing of personal neutron dosemeters in the workplace and also in interpreting their readings.