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Thesis. Lithium fluoride crystals, with TlF added to the charge, were prepared by the Bridgman- Stockbarger method. The scintillation response to photon energies between 25 and 1250 keV for these crystals and a commercially prepared LiF (Ti) crystal was studied. The response of the LiF (Ti) crystal was compared to the response of an NE109 scintillator at 1250 keV. The dose response of the LiF (Ti) crystal was evaluated over the energy range 25 to 1250 keV. The absorption and emission spectra of the LiF (Ti) crystal are discussed. A historical review precedes the discussion. (auth)

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Thesis. Delayed neutron characteristics of six fission product nuclides were determined using a mass separator operated on-line with a nuclear reactor. Beta-decay half-lives were- measured using neutron multiscaling techniques for the precursors /sup 88/Br, /sup 89/Br, /sup 98/Kr, /sup 93/Kr, /sup 137/I, and / sup 138/I. The observed half-lives were 16.52 plus or minus .17 seconds, respectively.. Energy spectra were measured for delayed neutrons emitted in the beta-decays of /sup 17/N, /sup 137/I, /sup 93/Kr , and /sup 93/Rb. The spectra of neutron emissions in the mass 93 parentdaughter decay chain were observed using a moving tape collector to effect isobaric separation. Two different types of /sup 3/He- filled neutron spectrometer were used to determine the spectra; a proportional counter with risetime discrimination electronics, and a high resolution ionization chamber. The measured delayed, neutron spectra using both detector types are presented, and the results compared, where possible, with other reported measurements. (auth)

Thesis. The development of a directional high energy (20 to 160 MeV) neutron detector which was flown to satellite altitudes (500 km; circular equatorial orbit) in the NASA Orbiting Solar Observatory (OSO-6) in August 1969 is described. Both the angle of incidence and the energy of the neutron are determined by a proton-recoil telescope (Pilot B scintillation plastic) which provides the source for proton-recoils and defines the dE/dX versus E method for particle identification and energy determination. The telescope is embedded in a scintillation plastic guard counter envelope which eliminates the unwanted charged particle background as well as recoil protons (electrons) whose energies and direction do not satisfy neutron (gamma-ray) detection requirements, respectively. Results from a Monte Carlo calculation indicate that the overall average efficiency within an average angular acceptance of about 29 deg (FWHM) is approximately (2.25 plus or minus 0.113) x 10/sup -4/. The inflight calibration procedure, the main frame data bit error analysis, and the method for determining the orientation of the detector axis in the spacecraft spin plane are described. Results indicate a discrepancy in the measured (0.461 x 10/sup -2/ plus or minus 0.254 x 10/sup -2/ n/cm/sup 2/sec) and theoretical (2 to 70 n/cm/ …

The high-temperature internal friction of germanium and silicon, intrinsic and highly n-type, was measured as a function of temperature, frequency, dislocation density, and dopant concentration. Two features found in the internal-friction spectrum were investigated. At moderate temperatures in both materials, when not too highly doped, there appears a peak, the features of which are independent of dislocation density, due to the acousto-electric effect. The high-temperature dislocation-dependent damping in intrinsic and intrinsic- behaving germanium and silicon was found to agree well with most previous studies. If deformed at high temperature and allowed to anneal, highly doped, n-type material behaved intrinsically due to preferential precipitation at dislocations. if deformed at minimum temperatures and not allowed to anneal, a greatly enhanced dislocation-dependent internal friction was found that depended upon the extrinsic carrier concentration. (23 figures, 93 references) (DLC)

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Thesis submitted to Univ. of Tennessee, Knoxville. Statistical methods were used in an attempt to determine the effect of the tendency to report accidents on the systemic variance in minor injury data over a 6-yr period. The population surveyed included 245 journeymen of 9 skilled craft groups continuously employed during the period. Results indicate that injury and non- injury visits to the dispensary were relatively stable during the 6-yr period and that there was a significant positive relation between non-occupational and injury visits during the period of study. (C.H.)

The possibility of measuring the electromagnetic form factor of the pion by extrapolation of the cross section for e/sup -/ + p 1100 deg C are n + The effects of /sup +/ + e/sup -/ was investigated. The method is based on the existence of a pole in the electropionproduction scattering amplitude as a function of the invariant momentum-transfer of the nucleon. The residue of this pole is the pion form factor multiplied by a known coefficient. Since the pole lies slightly outside the physical region of the invariant momentum transfer, an extrapolation of the experimental data is required. An approximate calculation of the electropion-production cross section was made in order to estimate the experimental accuracy necessary for a significant extrapolation. Accuracy is required which is an order of magnitude better than that achieved at present in similar experiments. (auth)

Report discussing a study aiming to find which electronic state of the C2 molecule is the groud state.

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