THE IRRADIATION OF THIN EVAPORATED FILMS OF URANIUM DIOXIDE. Interim Report

Technical Report · Tue Sep 01 04:00:00 EDT 1959

OSTI ID:4206741

Bierlein, T K; Mastel, B

Electron microscopy of evaporated films of uranium dioxide, irradiated at a temperature below 60 deg C to an exposure of 2.3 x 10/sup 16/ nvt, thermal, (2.38 x 10/sup 15/ fissions/cc: 1.6 x 10/sup -3/ at.% depletion of U/sup 235/: or 3.8 x 10/sup -6/ at.% burnup of all atoms), discloses the presence of fission fragment trajectories with diaroeters of 150 A. Each of the continuous trajectories observed corresponds to a fission event in the film. Irradiation of the film to higher exposures obliterates the fission trajectories and for exposures of 4 x 10/sup 19/ nvt the original homogeneous film has reverted to a heterogeneous film from which isolated flocculent growths of uranium dioxide emanate. The relative intensities of the various tines which comprise the electron diffraction pattern of the thin uranium dioxide films change during irradiation. After an exposure to 8.4 x 10/sup 18/ nvt a new, unidentified line with an interplanar spacing of 3.43 A appears. After an exposure to 2 x 10/sup 19/ nvt all the sharp diffraction lines disappear and only two extremely broad diffraction bands persist: sharp diffraction lines again develop during further irradiation exposure to 4.4 x 10/sup 19/ nvt. Interplanar spacings for the thin evaporated films appear to have a maximum value after an exposure of 4 x 10/sup 17/ nvt. (auth) 673O Absolute and relative measurements were made of the energy required to produce F centers in pure and sensitized alkali halide crystals by bombardment with electrons and deuterons accelerated in a Van de Graaff generator. In KBr + KH exposed to 1.2-Mev electrons, 35 ev were required per F center. This value is in agreement with other published data. A value of approximately 100 ev was required with deuterons and KBr + KH. Slightly lower yields were found for several other salts. The specific ionizations of electrons, deuterons. and gamma rays were investigated and used to determine the acceleratcr beam size and penetration. The ranges of electrons in K-Br, KCl, and NaCl were measured as a function of accelerator voltage and found to agree well with ranges predicted by the Feather rule. Energy transport and features of the specific ionization pattern are discussed in terms of the Seitz synthesis of crystal imperfections. (auth)

• Research Organization: General Electric Co. Hanford Atomic Products Operation, Richland, Wash.
• DOE Contract Number: AT(45-1)-1350
• NSA Number: NSA-14-006729
• OSTI ID: 4206741
• Report Number(s): HW-61656
• Country of Publication: United States
• Language: English

Related Subjects

BURNUP
DEFECTS
DIFFRACTION
DISTRIBUTION
ELECTRON MICROSCOPY
EVAPORATION
EXPANSION
FILMS
FISSION
FISSION PRODUCTS
HOMOGENEOUS REACTORS
IRRADIATION
METALS
CERAMICS AND MATERIALS
NEUTRON BEAMS
PARTICLE TRACKS
SPECTRA
THERMAL NEUTRONS
URANIUM DIOXIDE