Work on the present relativistic electron bunching accelerator (S-band rebatron) is concerned with improving the electron bunching, current and beam focusing, and the design of a portable prototype system. Most of the parts for this new machine were fabricated and tested and the construction initiated. A photograph showing the present stage of construction is given. Since an S-band rebatron cannot be scaled directly to X-band, a lower voltage Xband rebatron, followed by a short section of a linear accelerator could solve the problera. An Electronics Associates analog computer was received and is being programmed to explore the design problems. The numerical work of evaluating the TM and TE modes of teflon dielectric cavities is largely completed. New ideas and further modifications are being tried in Si crystal harmonic multipliers for use as sources for testing components. The new klystrons now being used permit driving the crystals harder, and hence improve the harmonic power. (For preceding period see AECU-3535.) (M.H.R.)

Thermal neutron spectra were measured with timeof-flight techniques. Spectra were obtained for pure water and for a nearly homogeneous subcritical assembly where the ratio of themal absorption to high energy scattering cross section was t 125, 150, 175 0.3. For each medium, spectra were measured at 298 and 586 K. The experimental results are presented and compared with calculated theoretical spectra The agreement between theory and experiment is excellent for the multiplying media. On the basis of this agreement, one concludes that chemical binding effects in light water play a negligible role in determining the equllibrium neutron spectrum in water assemblies. (auth)

This is the monthly report for the Hanford Laboratories Operation, September 1957. Metallurgy, reactor fuels, chemistry, dosimetry, separation processes, reactor technology, financial activities, visits, biology operation, physics and instrumentation research, and employee relations are discussed.