Comparison of tissue-equivalent ionization chambers and silicon diodes for measuring fast neutron dose

Tissue-equivalent ion chambers and thermoluminescent dosemeters were used to measure fast neutron dose in large tissue-equivalent phantoms. Gamma-rays were present in addition to fast neutrons, and since the ion chambers responded to the combined dose from these radiations, the gamma -ray dose component was measured separately with thermoluminescent dosemeters. The fast neutron doses were also measured with silicon diodes by utilizing the decrease in electrical conductance of the diode, caused by damage to the silicon crystal lattice. Gamma-rays did not affect the diode conductance significantly. The diodes underestimated the neutron dose by amounts which depended on depth in the phantoms, and correction factors are given.