Use of Ferroelectrics for Gamma-Ray Dosimetry

A gamma-ray dosimeter employing a poled ferroelectric as the transducer element has been studied. Irradiation with gamma rays causes a release of charge by the ferroelectric element. The magnitude of the charge released has been determined experimentally to vary linearly with gamma-ray dose. The current in a shunting resistor with no external voltage applied varies linearly with gamma-ray dose rate. A constant of proportionality of 10-12 coul per rad (H2O) per cm2 of electroded ferroelectric surface has been measured for polycrystalline Pb(Zr.65 Ti.35)O3 + 1 w% Nb2O5 irradiated in the Sandia Pulsed Reactor. The contribution to the charge release from the neutron irradiation has been determined experimentally to be negligible. Irradiation in the 0.6 Mvp flash X-ray also produces a linear relationship between current and gamma-ray dose rate. A similar release of charge has been observed in poled ceramic barium titanate.