Fluence-to-Dose Coefficient Angular Dependence Factors for Rod and Pillar Phantoms Irradiated by Broad Beams of Beta Particles

Fluence-to-absorbed dose conversion coefficients and their variations with angle of incidence have been computed for monoenergetic beams of beta panicles incident on rod and pillar ICRU tissue phantoms. Such phantoms are used for calibration of ring and wrist or ankle dosemeters for measurement of persona! dose equivalent to the skin. Calculations were performed for beams normal to the axes of the cylindrical phantoms. Results are reported for the standard sources 147 Pm, 204 Tl, 90 Sr: 90 Y. and 85 Kr, and a number of technologically important sources such as 24 Na and 60 Co. For the sources used in the PTB Beta Secondary Standard, results are also reported for the energy spectra after beta particle passage through encapsulation and filtration.