Real-time single-ion hit position detecting system for cell irradiation

Abstract

We have developed a real-time single-ion hit position detecting system to replace a CR-39 solid-state nuclear-track detector for cell irradiation experiments because the CR-39 takes several minutes for off-line etching. The new real-time system consists of a 500-μm-thick CaF2(Eu) scintillator, an optical microscope with a 10× objective lens, and a high-gain charge-coupled device camera. Each of the 260-MeV neon ions passing through a 100-μm-thick CR-39 sheet was detected using the real-time system in a performance test for the spatial resolution. The full width at half maxima (FWHMs) of the distances between positions detected by the real-time system and the centers of the etch pits on CR-39 were 6.5 and 6.9μm in the x and y directions, respectively. The result shows that the system is useful for typical cultured cells of a few tens of micrometers in size.