The following document describes the usage of the LRL 9-ZOOM code, a neutron diffusion theory reactor code for the IBM 709. The code has been modified to solve configuration of a series of stacked cylindrical disks, designating a new geometry case.

Abstract: "Discussion is directed toward eventual optimization of the largest diffusion-pump systems. Less than 100 diffusion pump fluid molecules per cm 2/sec are possible to detect using an accumulation method. Optimization discussed demands highest possible system speed compatible with the above contamination rate. Bakeable oil diffusion pump systems, with equal orifice valve-tap units, without conventional baffling, permit theoretical through-put speeds up to 0.3 of the system orifice. The average backstreaming rate of oil in two unconventionally baffled commercial pumps of 6-in. and 10-in. size is reduced to < 3 x 10-(-4) g/cm-2/24 hr, including heating and cooling the pump boiler. A Ho factor of >0.4 is maintained. Results on trapping with activated alumina, retained by a wire mesh, at both liquid-nitrogen and room temperature are included. A variety of pumping speed measurements and bakeable combination valve-trap units are discussed."

Abstract. The cross section of photoneutron production in Be9 at energies of 1.692, 1.720, and 1.78 Mev has been investigated using radioisotope gamma-ray sources. Neutron counting was by manganous sulfate bathe and a long counter. Gamma-ray counting was by a scintillation spectrometer consisting of a NaI(T1) scintillation crystal and a 256 channel pulse-height analyzer. A theoretical treatment of the P [right arrow] S transition near threshold using square-well potentials is also presented.