An apparatus giving an -particle microbeam for the irradiation of living cells

Abstract

A micro-scope fitted for phase contrast observation is modified so that a biological specimen in the centre of the field of view may be irradiated with [alpha]-particles. A beam of [alpha]-particles is obtained from a polonium source by a glass capillary collimating tube of 15 [mu] internal diameter, the source and collimator being mounted in a tube passing axially through the optical condenser. The irradiation rate is of the order of 1 particle/min and 70% of the particles lie within a circle of 30 [mu] diameter in the focal plane of the objective. A statistical method is used to calculate the probability of irradiation of a target of known size which is irradiated for a known time.