USE OF PHOTODIODE IN MICRODOSIMETRY AND EVALUATION OF EFFECTIVE QUALITY FACTOR

A silicon photodiode in conjunction with a charged particle radiator p laced in front of the sensitive layer was employed to construct a micr odosimetric detector. Silicon photodiodes of different types (PN, PIN and PNN) and of different sensitive layers (1, 3, 5 and 8 mu m) were u sed to obtain the pulse height spectrum for an Am-Be neutron source. T he data were analysed to determine the microdosimetric spectra and the effective quality factor (Q) over bar was estimated. Two types of cor rections were needed for the estimate of (Q) over bar. One is related to the weighting function Q(L) and the other deals with the fractional relative dose d(L). The results were compared with those obtained wit h Tissue Equivalent Proportional Counter (TEPC) of 1 mu m simulated di ameter and were found to be in good agreement. (C) 1998 Elsevier Scien ce B.V. All rights reserved.