Alpha particle energy and fluence dependence of polycarbonate detectors

Polycarbonate track detectors (PCTDs) processed by electrochemical etching (ECE) have been extensively instrumental in wide-scale radon monitoring, individual neutron dosimetry, photoneutron dosimetry, 4π ion emission image detection in plasma focus devices, etc. In particular, determination of unknown ion fluences and energy requires having detailed information on efficiency and diameter of tracks of ions such as helium or alpha particles over a broad fluence and energy ranges especially at high fluences. In this context, the effects of alpha fluence and energy on detection efficiency and track diameter in 250 μm thick PCTDs processed by 50 Hz-HV ECE method were studied. Alpha particles of known fluences up to ∼6.0 × 106 alphas.cm−2 with energies from ∼0.3 to ∼5.0 MeV were applied. Groups of responses on track density and diameter versus fluence at different energies, efficiency versus fluence at different energies and versus energy at different fluences were developed. The efficiency decreases as fluence increases. The efficiency energy responses have Bragg curve trend with near 100% efficiency at the peak for a fluence of ∼1.0 × 103 alphas.cm−2. Mean track diameter responses decrease linearly as energy increases at different fluences studied. While the track density is linear up to an upper detection limit of ∼3.0 × 106 alphas.cm−2 at all energies, strong dependence of efficiency and track diameter on alpha energy and fluence should be highly considered in any application requiring analysis of such parameters.