A STUDY ON NATURAL BACKGROUND NEUTRON DOSE

In order to monitor the neutron dose in the environment of the Synchro tron Radiation Research Center, the sensitivity of the monitor system to the natural background cosmic-ray neutrons must be established. Lar ge-size BF3 counters with and without an 8.5-cm polyethylene enclosure were used to measure the cosmic-ray neutrons in the Nuclear Engineeri ng Building, NTHU. The response functions of the BF3 counters were cal culated by using ANISN code performed in adjoint mode. By applying the cosmic-ray neutron spectrum and the detector response functions the m easured counting rates of the BF3 counters were converted to deliver t he annual dose of cosmic-ray neutrons. The shielding effect of the con crete slabs and windows of the building was determined by the measured data and compared to that predicted by neutron transport calculations .