Particle size effect in CaF2:Mn/Teflon TLD response at photon energies from 5-1250 keV

Thermoluminescent dosimeters (TDLs) fabricated by embedding CaF ₂:Mn powder in a Teflon matrix (TTLDs) are sometimes used to monitor dose in silicon-device radiation effects experiments. A potential advantage of TTLDs over other types of TLDs for this application is that their weighted-average mass energy-absorption coefficient is near that of Si. Experimental results are presented which demonstrate that for moderate-energy X-rays, particle size effects have a very substantial influence on the spectral response of a typical batch of 30%-loaded CaF₂:Mn Teflon TLDs relative to Si. Above 50 keV, by offsetting the effects of weighted-average mass energy-absorption coefficients, particle size effects slightly improve the agreement in absorbed dose between TTLDs and Si. However, below 50 keV particle size effects become dominant, increasing TTLD response relative to Si by as much as threefold