An arrangement for irradiating cultured mammalian cells with aluminium characteristic ultrasoft x-rays.

Ultrasoft x-rays are useful for testing the validity of mechanistic models of biological damage caused by radiation. Described here is the construction and operation of a cold-cathode transmission-target discharge tube for irradiating mammalian cells in vitro with aluminium characteristic x-rays (1.487 keV). Particular attention is given to the problems of sample preparation and dosimetry for this shallowly penetrating radiation. The proportion of contaminating bremsstrahlung radiation is measured to establish the optimum operating conditions. Preliminary data from experiments using V79 Chinese hamster cells show that aluminium characteristic x-rays are about twice as effective at inactivating the cells as 250 kVp x-rays.