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A thermoluminescence sensitivity technique is used to give a new measurement of the degree of metamorphism of unequilibrated ordinary chondrites. Consequently the petrological assignment of these meteorites is modified.

Sputtering yields of solid SO2 by high energy ions were measured in order to study the mechanism for sputtering dielectrics with ions in the electronic stopping power region. The incident ions were helium and fluorine with energies ranging from 1.5 MeV to 25 MeV. Yields as high as 7000 SO2 molecules/incident F ion were measured; the 1.5 MeV 4He beam had a sputtering yield of 50. The data are compared to yield measurements made on UF4 and H2O targets. There is a striking similarity in the yield as a function of the incident F energy for all three targets. The data compare favorably with theoretical yield curves based on a new model for the sputtering which considers the electronic excitations induced in the target by the incident beam. Measurements and calculations of this sort are also useful in understanding processes which occur on the surface of Jupiter's satellite Io, which is covered with SO2 frost and bombarded by energetic ions trapped in the Jovian magnetosphere.

Bismuth germanate (Bi4Ge3O12or ‘BGO’), primarily because of its higher detection efficiency, is beginning to replace NaI(Tl) as a scintillator for detection of γ rays in several applications, including large electromagnetic calorimeters for high-energy physics experiments1, computed tomography systems in medical physics2and γ-ray spectroscopy measurements in oil-well logging3. Although the use of BGO is increasing, the scintillation mechanism which converts incident γ-ray energy into visible light is not well understood and its efficiency (light output per unit energy of absorbed γ radiation) decreases following exposure to ultraviolet light or other radiation4. We have found that this ultraviolet ‘radiation damage’ is accompanied by a corresponding increase in a stored thermoluminescence signal—the first reported observation of thermoluminescence in BGO. Comparison of scintillation efficiency and thermoluminescence intensity following various exposures to ultraviolet light and after thermal annealing indicate a strong correlation between the scintillation efficiency and the electron population of the thermoluminescence traps. This should be a useful probe for investigating the scintillation mechanism of BGO.