Experiments with a Condenser Discharge X-Ray Tube

A condenser discharge x-ray tube is described from which it is possible to obtain a reproducible x-ray dose of 3.5 roentgens in about 5×${10}^{-6\mathrm{}}$ sec. The current through the tube was of the order several hundred amperes. The effects of these high intensity x-ray pulses have been compared with the effects of x-rays of ordinary intensity from a Coolidge tube operated at a current of about 1 ma. The ordinary small chamber dosimeter was found to have a large recombination error for the high intensity pulses. The Bunsen-Roscoe reciprocity law was found to hold for the blackening of photographic plates, and for the coloration of crystals, by the high intensity pulses. Biological effects produced by the high intensity pulses in drosophila eggs, in the spores of aspergillus niger, and in wheat seedlings were found to be approximately the same as those produced by equal doses of x-rays of ordinary intensity.