Radiation damage studies of metal specimens have been achieved by using a Van de Graaff accelerator to supply energetic electrons. The irradiating electrons are magnetically deflected so that the electron beam bombards a well‐defined rectangular area. A method is described which is used to determine the location of the beam with respect to the position of the specimen. A low temperature thermal switch is discussed in terms of its theroetical and and experimental behavior. A practical method for improving the thermal contact between the specimen and its holder by using the helium exchange gas technique is described. Estimates of the degree of thermal contact between specimen and specimen holder are possible because of the particular electrical circuit in the experimental chamber.