Mean Quality Factor Research Articles

Radiation Quality of Californium-252

The radiation quality of 252Cf has been determined in a tissue-equivalentphantom for simulated sample sizes of 1 and 2 μm. The measurements were made with a2.54 cm spherical proportional counter of tissue-equivalent plastic with a source-to-counter distance of 7.8 cm. Event spectra have been obtained for lineal energydensities between 0.04 and 103 keV μm-1. The distributions in both lineal energydensity and LET are presented. The dose mean of the distribution in linealenergy density is 38 keV μm-1 for the 1 μm site and 34 keV μm-1 for the 2 μm site.Correspondingly, the dose mean values of the distribution in LET are 34 and30 keV μm-1 respectively. A mean quality factor of about six for 252Cf is obtained forthe geometry used here. The absorbed dose rate per unit source mass was found to be11 rad s-1 g-1, in substantial agreement with most previous measurements, and theratio of absorbed dose due to protons and other heavy particles to that of electrons isapproximately 0.9.

A method of determining the fast neutron dose equivalent

The paper describes a method to determine the fast neutron dose equivalent (DE) by using experimental data gained with the Hurst proportional counter. Such data have till now been extensively employed to measure tissue first collision dose. The DE determination is accomplished deducing from proportional counter data the LET spectrum of H and C recoils, calculating through them the mean quality factor for first collision (fc) dose and then arriving at the DE by means of a build-up factor. A graphical simplification makes the method very practical.