A Multiple Radiation Effects Facility for the Study of Structural and Flexible Materials Exposed to the Space Environment
A radiation effects facility is described which utilizes multiple radiation sources, vacuum chambers and thermal control to simulate the space environment. Use of the facility for eight months' continuous testing of thin film flexible materials is discussed and summary results, primarily from in-situ testing, are presented.
Development of a ground-based facility for simulating the omnidirectional near-earth electron environment
Abstract A method is detailed for simulating in the laboratory the omnidirectional near-earth electron environment. This technique can synthesize the directional and energy properties of an arbitrary omnidirectional electron flux by combining a sufficient number of weighted energy and direction increments. A large vacuum chamber has been built, capable of holding three-dimensional structures up to 30 cm in each dimension while maintaining pressures in the 10−6 mm Hg range. The support structure in the chamber rotates around two axes, thereby achieving all angular orientations necessary for the omnidirectional simulation. This chamber was coupled with a beam scanning system to a 4 MeV electron Van de Graaff accelerator which was tuned to provide specified fluences of electrons at the desired energies. The system was used to irradiate a series of hollow aluminum cubes having varying wall thicknesses. Using radiochromic film dosimeters, dose profiles were mapped in the interiors for both one-wall and six-wall exposures. Results of the dose mapping are presented for several monoenergetic cases as well as for the energy spectra from a 235U fission event. The one-wall exposures show dose variations within the interior by a factor of 3.2 ± 0.6 independent of energy or wall thickness. In the six-wall exposure, distributions varied only about 15%.
The Yield of Oxidation of Ferrous Sulfate in Acid Solution by High‐Energy Cathode Rays
An absolute determination of the yield of the ferrous sulfate radiation dosimeter has been made by delivering to the solution a measured charge of cathode rays at known energies of 1 or 2 Mev. Appropriate small corrections have been made for backscattering, window absorption and, bremsstrahlung. The result, G = 15.6±0.5, is in complete agreement with Hochanadel's calorimetric determination of the yield, but disagrees by 30 percent with the most widely used value obtained by cavity ion chamber comparison.