A versatile plutonium-238 irradiator for radiobiological studies with α-particles

A versatile irradiator has been constructed for in vitro irradiation of mammalian cells with α-particles of well-defined energy, LET, direction, dose and dose rate. It is based on ∼ 1.2 x 109 Bq of 238Pu (on a platinum disc) contained in a He-filled chamber. In a standard configuration, monolayers of cells grown in 10 Hostaphan-based dishes are irradiated with 3.26 ± 0.22 MeV α-particles (LET 121 keV μm-1) at selectable dose rates from ∼ 2 Gy min-1 down to < 10-4 Gy min-1 (i.e. fluence rates of 1 x 107 cm-2 min-1 to 3 x 102 cm-2 min-1). Single dishes can be irradiated at dose rates up to 24 Gy min-1 (fluence rate 1 x 108 cm-2 min-1). Incident energy and LET can be varied from 0.8 to 4.2 MeV and 266 to 102 keV μm-1, respectively. The irradiator has full incubation and gassing facilities for protracted irradiations. (author)