Silicon Solar Cells for Post-Detonation Monitoring and Gamma-Radiation Effects

The feasibility of using solar cells for post-detonation monitoring, and more broadly, gamma-ray monitoring, is evaluated using Monte Carlo simulations and experiments in this work. We measured the short-circuit current I_sc response of commercial silicon (Si) solar cells to ¹³⁷Cs and ⁶⁰Co gamma rays. A clear response of both mono- and polycrystalline Si solar cells to ¹³⁷Cs and ⁶⁰Co gamma rays was obtained in good agreement with the simulations. Radiation effects in solar cells due to accumulated gamma-ray dose were noticed as the drop in I_sc and open-circuit voltage V_oc. The atomic displacement cross section of the produced secondary fast electrons and nonionizing energy loss (NIEL) concepts were revisited to understand the principal gamma-radiation damage mechanism in solar cell devices. Analytical computations of and NIEL of electrons convoluted with simulated Compton electron distributions in Si enabled a fundamental understanding of the gamma-radiation effects and recovery mechanism in solar cells, further supporting the experimental results. Different from the ionization effects in the polymer and glass layers of a solar cell/panel, displacement damage in the Si p-n layer from gamma rays or fast electrons is much less than that from massive particles, which directly affects the charge collection performance fundamental to solar cell operation.