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The compressibility of a sample of very pure methane has been measured with high precision from 0°C to 150°C and over a pressure range of about 20 to 230 atmos. The precision attained is of the order of 1 part in 104. Small but consistent discrepancies exist between the present results and earlier measurements, and it is believed these discrepancies are the result of a small impurity of ethane in the methane used earlier. The virial coefficients of methane are redetermined from the present measurements, and the intermolecular forces of methane are calculated from the second virial coefficient for several forms of force laws. These force laws are then used to calculate the third virial coefficient, the crystal properties at 0°K, and the viscosity for comparison with experiment. All the force laws fit the second virial coefficient very well, but some can be eliminated on the basis of the other properties.

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The effect of nuclear alignment on the total cross section of the highly deformed 165 Ho nucleus has been measured using 14-MeV neutrons. The aligned 165 Ho target was obtained by cooling a metal single crystal to 0.33 °K. A finely collimated beam of 14-MeV neutrons was produced by careful collimation of the alpha particle produced in the 3 H(i,^) 4 He reaction and by detecting it in fast coincidence with its associated neutron. The measured total cross section is 5.29±0.10 b. The fractional change in the total cross section, for our value of nuclear alignment (/2=0.31), is + (3.52±0.75)%, where the positive sign indicates a larger cross section for nuclei aligned perpendicular to the incident beam than for randomly oriented nuclei. These results are in excellent agreement with the predictions of the optical model using an adiabatic coupledchannel calculation. The optical-model parameters used are in good agreement with those obtained from other measurements, and in particular the value of the deformation parameter j8 = +0.30 is the same as that used in our earlier work. It was also found that 14 MeV is not yet a sufficiently high energy to use the black-nucleus model to interpret our results. «T. Tamura, Rev. Mod.

Over the century that radioactive materials have been mined, processed, produced, and utilized, many sites across the United States have become contaminated. Such sites include bases and installations of the Department of Defense, weapons production and research facilities of the Department of Energy, properties under the authority of other Federal agencies, privately-owned and governmental facilities that are licensed by the Nuclear Regulatory Commission and its Agreement States, and sites licensed by or the responsibility of states. This review reports on aspects of work by the Environmental Protection Agency, the Department of Defense, the Department of Energy, the Nuclear Regulatory Commission, and others to identify sites contaminated with radioactive materials. It also describes the principal programs that have been instituted to deal with them.

A target for the production of neutrons by the D(d,n) He3 reaction is described. The target gas is circulated to cool the foils used as entrance and exit windows for the incident deuteron beam. Low mass construction is employed to minimize the scattering of neutrons.

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