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Pomeron- pomeron-2 pi vertices were sought in the reaction pi /sup -/p yields pi /sup -/ pi /sup +/ pi /sup -/p at 205 GeV/c. From a sample of 1 86 of these events, about 2/3 were extracted for which the rapidity ordering of the four outgoing particles makes them candidates for the double-Pomeron exchange process (i.e., the fastest and the slowest particle are respectively a pi /sup -/ and a proton). A separation from single-Pomeron processes was attempted with the help of a rapidity triangle plot. The number of possible double-Pomeron-type events was also estimated from a Regge-propagator fit to the nonhomogeneous distribution of the events within this triangle. The number of such events obtained by either method gives a cross section upper limit of 85 mu b for double-Pomeron exchange, consistent with the predictions of a pion-pole dominance model. (auth)

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Some features of bremsstrahlung radiation are reviewed for visible region photons with possible applications to ISA luminosity measurements. (auth)

A Deck-like model for the reaction pi /sup -/p yields pi /sup -/ pi / sup +/ pi /sup -/p is formulated and studied. The model differs from previous Deck calculations in two respects: i) experimental data are used for both pi pi and pi N scattering, and ii) the amplitude has proper Bose symmetry. Feature i) allows one to examine any desired region of 3 pi mass (the A/sub 3/ is treated on the same footing as the A/sub 1/); features i) and ii) allow one to examine all the angular dependence in the final state and to compare with partinl wave analyses of experimental data. The results of a study are presented in which events generated from the model by a Monte Carlo method are plotted and fit in the same way as experimental events. Many of the features of the data are qualitatively reproduced including certain important properties obtained from the partial wave analysis in the A/sub 1/ region. The A/sub 3/ region is not accurately representcd by the model. (auth)

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ABS>The application of a high-precision Cary Model 16 spectrophotometer to the differential spectrophotometric determination of plutonium(III) was investigated. The absorbances of plutonium(III) solutions were measured against colored glass filters at 560 nanometers. Selection of various instrument parameters and the determination of the best reference filter for the highest precision are discussed. Two sets of calibration points were analyzed, The absorbance for each set was measured once a day for three days. A statistical comparison between the three readings, the three least squares curves, and the two sets of calibration points are discussed. The standard deviation of the average reading about the line was plus or minus 0.0028 g/liter plutonium in the 11 to 15 g/liter plutonium range. Detailed procedures for standard preparation from plutonium nitrate and for operation of the Cary Model 16 are included. The advantages and disadvantages of the equipment and method are discussed and further experiments suggested. (auth)

The mechanical properties of Nugget sandstone have been determined from a number of independent measurements at pressures up to 30 kbar. Pressure- volume, strength, uniaxial stress, and uniaxial strain tests yield the failure surface and effective moduli as a function of stress state, i.e., mean pressure and shear stress. Acoustic velocity determinations provide the effective moduli for low-amplitude dynamic waves. At atmospheric pressure the initial effective bulk modulus in tests with applied differential stresses (~40 kbar) differs from that determined hydrostatically (23 kbar). This and a large pressure derivative of the shear modulus at low pressure are believed to be due to an abundance of cracks with low aspect ratios. The initial effective shear modulus of about 55 kbar increases rapidly with the closing of cracks. At 1 kbar confining pressure, a shear modulus of about l20 kbar is determined in both uniaxial stress and uniaxial strain experiments. The rock has an ultimate strength comparable to granite (1.2 kbar unconfined) and exhibits brittle behavior at failure to the highest mean pressure studied (14 kbar). Failure is preceded by dilatant behavior. (auth)

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