The phase shifts for proton-proton scattering as calculated from the one-pion exchange contribution (OPEC) alone are of some interest because they describe the scattering correctly in the high angular momentum states, and because in the lower angular momentum states the deviation from the OPEC phases is an indication of the strength of the two-pion and higher exchanges processes. The attached table gives the proton-proton nuclear-bar phase shifts as calculated from OPEC. Phase shifts and mixing parameters are given in degrees, as function of the T, the laboratory kinetic energy of the incoming protons in Mev. Phase shift and mixing parameters are listed in the angular momentum states.

Quarterly progress report discussing activities related to the Vallecitos Boiling Water Reactor (VBWR) and related facilities.

Based on the assumption that the noise contribution of a semiconductor detector is due solely to the bulk properties of the semiconductor, equations are presented which indicate the theoretical limits of noise in detector-amplifier combinations. These equations show that an optimum amplifier time constant and detector bias voltage exist for which condition the minimum noise is independent of the semiconductor resistivity. The optimum performance of a detector-amplifier system is shown to depend only upon detector area, input capacity (less detector capacity), semiconductor minority carrier lifetime, and the transconductance of the amplifier input tube. A new detector structure including a guard-ring electrode as an integral part of the detector structure is described which largely eliminates noise due to surface leakage. Experimental results for detector leakage and energy resolution are presented which agree well with theory.

aluminum has been considered as a material for cladding fuel elements to be used in reactors cooled by high-temperature recirculating water. Aluminum is abundant, chap, has a relatively low cross section for thermal neutrons, and is readily fabricated into complex shapes. For these reasons, it appears that the use of aluminum rather than steel, Zircaloy or other candidate materials for fuel element cladding, would result in considerable savings in operating expense. The actual economics will of course depend on specific factors such as core materials and design of the reactor/. Aluminum appears particularly attractive for cladding the cores of aluminum-plutonium alloy proposed for the Plutonium Recycle Test Reactor since, in this case, the physical characteristics of the core and cladding would be practically identical.

From abstract: The principal efforts during the fourth project quarter were the near-completion of the final design and preparation of specifications for plant components. Reactor development work included final preparations for the flexible zero-power test (PMZ-1) program and revised fuel element irradiation test program, continuation of reactor flow test, further work on heat transfer test program, and final design and fabrication of the prototype magnetic jack-type control rod actuators.