THE EFFECT OF TRIPLET PRODUCTION ON PAIR COMPTON CASCADES IN THERMAL-RADIATION

We calculate the spectrum of photons resulting from electromagnetic ca scades through thermal radiation, and examine the consequences of incl uding triplet production in these cascades. We assume that the cascade is one-dimensional, and we find that this approximation is justified in the present work for thermal radiation with temperature less than 1 0(-3) mc2. Results are obtained for both monoenergetic and power-law p rimary spectra, and for a variety of path lengths. We find that triple t production is particularly important in electron photon cascades thr ough thermal radiation when the primary energy exceeds 10(5) m2c4/kT f or propagation over small path lengths. The importance of triplet prod uction decreases as the path length increases, and it has no effect on saturated cascades.