Neutron Dose Conversion Factors for Pube and Pobe Sources

A calculational program and an experimental program were conducted to determine the average first-collision tissue dose in rad/neutron per cm2 produced by PuBe and PoBe neutron sources. Calculated values were obtained using a number of published spectra which were weighted according to the first-collision tissue dose as a function of neutron energy. In addition, a direct measurement was made of the energy deposited by the neutrons in a polyethylene-lined, cyclopropane-filled proportional counter. Calculated values were 4.08 ± 0.20 × 10−9 rad/n/cm2 for PoBe and 3.90 ± 0.06 × 10−9 rad/n/cm2 for PuBe. The corresponding experimental values were 4.0 ± 0.2 × 10−9 rad/n/cm2 for PoBe and 3.9 ± 0.2 × 10−9 rad/n/cm2 for PuBe sources.