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A high-efficiency detector system developed especially for medical imaging has three specially cut Ge(Li) coaxial detectors (total volume 249 cm$sup 3$). At 122 keV, the peak efficiency is 93 percent of that of a 7.6 x 7.6 cm NaI (Tl) detector. Degradation of the paralleled energy resolution is avoided and resolution is improved by 35 percent over that of conventional output-summing techniques by gating the detector outputs. In effect this multiplexes them to a single line output. (auth)

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The original manual control system for the 12 neutral beam injectors on the 2XIIB Machine is being integrated with a computer control system. This, in turn, is a part of a multiple computer network comprised of the three computers which are involved in the operation and instrumentation of the 2XIIB experiment. The computer control system simplifies neutral beam operation and centralizes it to a single operating position. A special purpose console utilizes computer generated graphics and interactive function entry buttons to optimize the human/ machine interface. Through the facilities of the computer network, a high level control function will be implemented for the use of the experimenter in a remotely located experiment diagnositcs area. In addition to controlling the injectors in normal operation, the computer system provides automatic conditioning of the injectors, bringing rebuilt units back to full energy output with minimum loss of useful life. The computer system also provides detail archive data recording. (auth)

Helium in very low concentration (less than 1 atomic ppB) has been introduced into type 304 stainless steel by radioactive decay of dissolved tritium. Release of this helium during subsequent annealing was monitored with a high sensitivity mass spectrometric gas analyzer. With isochronal annealing, helium is released in two temperature ranges, one near 300$sup 0$C and the other between 800$sup 0$C and the melting point. The latter release is interpreted as attributable to helium gas bubbles. The release near 300$sup 0$C was studied isothermally between 150 and 300$sup 0$C and is analyzed in terms of two stages of exponential decay. The fast and slow release stages have relaxation times near 10$sup 2$ and 10$sup 3$ s, respectively, and the fast release accounts for roughly 85 percent of the total release at low temperature. From an analysis of the temperature dependence of the release rate, it is concluded that volume diffusion is the controlling mechanism for the outgassing. (auth)

The discovery of neutral currents in neutrino interactions has made necessary the recalculation of the neutrino flow during stellar collapse. Neutral currents cause a coherent scattering cross section of complex nuclei proportional to the square of the atomic weight. This allows neutrinos to escape easily from the hot, dense center where only free baryons exist. The neutrinos then interact strongly in the outer region of high atomic weight and, under certain circumstances, produce a supernovae-like explosion in the outer reaches of the star, leaving a neutron star behind. For an explosion to occur, the scattering in the envelope of heavy nuclei must be greater than the scattering of the free baryons in the core. In particular, with Friedman's interpretation of Weinberg's theory, the cross section ratio is insufficient to produce an explosion. Other theories state that suppressing the free baryon cross section does lead to an explosion. (auth)

The uniformity of wire characteristics is vital to the reliable long- time operation of the titanium alloy wire. Of particular importance is the diameter, total emissivity, and alloy mix. The getter wire must be operated at a minimum rate while the life is determined by the maximum rate. At a particular current the difference between the maximum and minimum rate is determined by variations in wire characteristics. Small percentage variations in these characteristics can result in large variations in gettering rate. (auth)

All major plasma diagnostic measurements from the 2XIIB experiment are recorded, digitized, and stored by the computer data acquisition system. The raw data is then examined, correlated, reduced, and useful portions are quickly retrieved which direct the future conduct of the plasma experiment. This is done in real time and on line while the data is current. The immediate availability of this pertinent data has accelerated the rate at which the 2XII personnel have been able to gain knowledge in the study of plasma containment and fusion interaction. The up time of the experiment is being used much more effectively than ever before. This paper describes the hardware configuration of our data system in relation to various plasma parameters measured, the advantages of powerful software routines to reduce and correlate the data, the present plans for expansion of the system, and the problems we have had to overcome in certain areas to meet our original goals. (auth)

Theoretical energy band structure calculations have been utilized to investigate several high-Z materials for potential use as ambient temperature radiation detectors. Using the pseudopotential technique, the band structure for HgI$sub 2$ has been determined and the effective masses of the holes and electrons have been estimated. Theoretical mobilities of the electrons and holes as a function of temperature have been computed for HgI$sub 2$ and CdTe and are compared to experimental data. (auth)

A test stand is in operation at LLL for the purpose of developing techniques and obtaining design information which will be used to develop efficient neutral beams. The knowledge gained will be used in the design of a 200 kV neutral beam test stand scheduled for operation in CY 77. (auth)

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