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Intense x-ray transition radiation can be generated when relativistic electrons pass through a multiple-foil target. When the foil spacing is periodic, the transition radiation can be spatially coherent with respect to the target period. The spatial coherence can be evident in the spectra and angular distributions of transition radiation from such targets. A series of experiments has measured coherent transition radiation distributions from multiple-foil targets (up to six foils) with spacings of 50 {mu}m and 100 {mu}m. The electron energy was about 75 MeV and the photon energies were about 200 eV. Agreement between calculation and experimental data is excellent.

Continued interest in high-energy {gamma} rays associated with fusion reactions has motivated an ongoing search for simple, effective measurement techniques. Past experiments have measured 16.7-MeV {gamma} rays with Compton-magnetic spectrometers. Some measurements have been performed with threshold Cherenkov detectors with enhanced sensitivity to high-energy {gamma} rays. The Compton spectrometers work quite well, but they require extensive calibrations and tend to be expensive and cumbersome. The threshold Cherenkov detectors are simpler to calibrate and physically compact, but have poor spectral definition and are vulnerable to background signals. This report is to describe a new type of {gamma}-ray detector, the MOLE, that may retain the simplicity of a threshold Cherenkov detector while still having sufficient energy discrimination to be effective for measuring high-energy {gamma}-rays in the presence of lower-energy {gamma}-ray fluxes.

Trois courtes experiences (6 mois a 1 an) sont effectuees pour preciser l'importance de cette predation sur la structure des biocenoses des substrats durs intertidaux de la Nouvelle Galles du Sud (Australie). Difficultes dans l'interpretation des resultats

The investigation of two poorly understood but technologically important physical properties of silicate glasses and related materials is described. The use of Electron Paramagnetic Resonance to investigate the nature of radiation-induced damage in glasses exposed to a variety of high-energy radiation sources is discussed first. Second, the measurement of the nonlinear index of refraction coefficient in a variety of optical materials related to the design of high-power laser systems is described. The radiation damage investigations rely heavily on the comparison of experimental results for different experimental situations. The comparison of EPR lineshapes, absolute spin densities and power saturation behavior is used to probe a variety of microscopic and macroscopic aspects of radiation damage in glasses. Comparison of radiation damage associated with exposure to gamma rays and fast neutrons (and combinations thereof) are interpreted in terms of the microscopic damage mechanisms which are expected to be associated with the specific radiations. Comparison of radiation damage behavior in different types of glasses is also interpreted in terms of the behavior expected for the specific materials. The body of data which is generated is found to be internally self-consistent and is also generally consistent with the radiation damage behavior expected for specific situations.more » A new and versatile technique for measuring the nonlinear index of refraction coefficient, n/sub 2/, in optical materials is described. The technique utilizes a 1 ns pulsed neodymium-glass laser system and time-resolved interferometry to determine the ratio of the coefficient n/sub 2/ of sample materials to the n/sub 2/ of CS/sub 2/. This method avoids some of the complications associated with performing absolute measurements of n/sub 2/ and allows the use of a relatively simple experimental technique. The measurements determine the nonlinear index ratios of the samples with an accuracy of about +-15 percent.« less

A NeUtron MOnochromator, NUMO, for (D,T) fusion diagnostics is described. The monochromator consists of CH/sub 2/ (n,p) converter foil, a sector-magnet monochromator and Faraday cup detector. This system can be used to study some details of (D,T) fusion reaction history. 6 refs., 5 figs.

Semen analysis of 59 ejaculates was undertaken. The ejaculates included pre-vasectomy semen postvasectomy necrospermic ejaculates and postvasectomy azoospermic ejaculates. Analysis after centrifuging revealed no significant changes in the activity of lactic dehydrogenase or glucose-phosphate isomerase or in the amount of protein or fructose in the 3 groups of semen. There was a significant negative correlation between time of ejaculation and enzyme activity.

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The enzymatic activity of glucose-phosphate isomerase was measured in cervical mucus from women using a diaphragm no contraception (controls) an IUD or some steroid method and from postcoital women. Determination of activity was performed through colorimetric measurement of fructose 6-phosphate formed from glucose 6-phosphate using the enzyme. The cycle was divided into the proliferative phase (days 1-11) the ovulatory phase (days 12-16) and the secretory phase (days 17-32). Among the diaphragm users and non-contraceptors whose enzyme activity was the least of the first three groups activity was significantly greater (p is less than 0.01) during the secretory phase than during either of the other phases. First phase activity in the IUD women was significantly greater (p is less than 0.01) than either second or third phase activity. No significant differences were found among the phases in the steroid women but this groups activity was consistently higher than the activity of the diaphragm or non-contraceptive or IUD group. Postcoital samples had less activity than random samples obtained on days 14 15 and 16 from non-contraceptors. Since semen contains a large activity the results shed doubt on the view that semen enters cervical secretion; or the results might reflect the greater amount of mucus in the postcoital samples. Enzymatic activity increased following secretion or administration of progesterone in the control and steroid groups but not in the IUD group. Since the enzyme takes part in the glycolytic pathway by catalyzing the reversible conversion of glucose 6-phosphate to fructose 6-phosphate the absence of fructose in human cervical mucus is puzzling. The suggested absence of glucose 6-phosphate was confirmed when fructose was formed after small quantities of glucose 6-phosphate were added to cervical secretion.

Use of vasectomy led to interest in the possible immunologic of biochemical changes in postvasectomized semen. A study of 66 ejaculates was made. After routine semen analysis leucine aminopeptidase and aspartate aminotransferase were correlated with sperm court. Semen may vary and the activity of some enzymes and motility are related to sperm concentration. No differences in protein fructose isocitric dehydrogenase or alanine aminotransferase were found. The significant difference in the amount of enzymatic activity of LAP was higher in the normal specimens decreased in the semen of oligospermic males and the postvasectomy semen and was least in the infertile group.

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