Radiation dose rate effects on the properties of a laser-induced breakdown spectroscopy system developed using a ceramics micro-laser for fiber-optic remote analysis

Abstract

Radiation dose rate effects on the properties of a compact fiber-optic laser-induced breakdown spectroscopy (LIBS) system with a monolithic Nd:YAG/Cr:YAG composite ceramics were investigated for remote analysis in a hazardous environment. To investigate radiation effects on the LIBS signal, properties related to the Nd:YAG laser operation such as oscillation threshold, output energy, oscillation timing, temporal pulse shape, and beam profile was measured as a function of the radiation dose rate from 0 to 10 kGy/hr in view of their influences to the signal. LIBS spectra of zirconium metal were measured under irradiation. Although signal intensity decreased considerably by irradiation, informative spectra were well obtained even at the maximum radiation dose rate. From the comparison of the LIBS-related parameters among the laser properties, the signal reduction was mainly ascribed to the pulse energy reduction. Scintillation emission spectra were also measured from the ceramics during the irradiation, where the signal intensity increased linearly with the dose rate. The results show that the developed system is applicable to effective remote elemental analysis and monitoring of radiation dose rate in hazardous environments such as nuclear fuel debris inspection.