This report discusses the multi-channel pulse analyser including its components and operation.

From cover page: This document has been assigned the above MDDC (Manhattan District Declassification) number, as given in the List of Declassified Documents issued semi-monthly by the Research Division, Manhattan District. In the case of Los Alapnos reports, LADC (Los Alamos Declassification) numbers are listed on the title page if known. This declassified document may differ materially from the original classified document by reason of deletions necessary to accomplish declassification. Hence, this copy of a declassified document does not constitute authority for declassification of classified copies of a similar document which may bear the same title and authors. Reference is made to District Circular Letter (Research Control 47-3) dated 31 October 1946, subject: "Instructions for Use of List of Declassified Documents," which outlines the procedure by means of which declassification of classified copies may be effected. Every effort has been made to reproduce with accuracy of detail the declassified document as certified for declassification. No corrections or changes have been made in the content of the document.

Abstract: The purpose of this research was to obtain data that would be useful in predicting changes that might be expected to occur in the oxidation state and degree of hydration of powdered uranium oxides maintained for long periods of time at temperatures between 30 and 300 degrees C. in the presence of excess water, hydrogen, oxygen and possibly hydrogen peroxide. The reaction of hydrogen and oxygen with water slurries of U3O8 were studied at 100-300 degree C.

From abstract: "This is a review, with annotated bibliography, of the mode of occurrence of the elements columbium and tantalum. It is not a list of specific ore deposits, but a summary of the types of minerals and rocks in which these elements have been reported to occur. In addition, the unpublished spectrographic studies of the Geological Survey are summarized, best sources for columbium and tantalum are indicated, and suggestions are made for further investigation."

This technical report is divided into two sections addressing two different chemical effects of nuclear transformations. The first section discusses the beta decay of lanthanum to cerium. The second section discusses the beta decay of selenium to bromine.

Technical report discussion of the complicated problem of the spatial distribution of slowed down neutrons. The introduction covers the current research on the topic. The following chapters cover the topics: (1) approximate treatment and its limitations, (2) age-velocity distribution, (3) general scheme of treatment based on transport equation, (4) Fermi's one-dimensional model, (5) moments, (6) remarks about the distribution function, and (7) point source.

This report discusses the field of nucleonics in the wake of the development of the atomic bomb, ruminating on the training and curriculum necessary for the next generation of chemical and nuclear engineers.

From abstract: "A pile will run steadily at an arbitrary level if it is just critical. For a pile not at equilibrium, equations of motion can be set up that contain as variables the pile power, the number of delayed neutron emitters and, in case it is of importance, also the pile temperature. The coefficients will depend on the average lifetime of the neutrons in the pile, the fractions and periods of delayed neutrons, temperature coefficients of resistivity and similar quantities. For a definite 'excess resistivity', which may be positive or negative, the power level will change exponentially with time with periods determined by the so-called 'labour' relation. For control and safety problems the transient behavior of the pile under reactivity changes has to be investigated. A number of limiting cases can be solved explicitly. A general method for the solution of the pile equations is available for small deviations from a steady state. In this case a pile impedance can be defined in close analogy to electric circuit theory."

From introduction: "The analysis of mixtures of fission products with a mass spectrograph offers certain advantages. A chemical separation of the fission products found in the solution at Hanford is not necessary with the mass spectrograph technique. A sample of the mixtures can be placed on the sample holder and then the sample holder is mounted in the mass spectrograph. This reduces the amount of handling of the active solutions to one relatively simple and short operation. The health hazards involved in the analysis can be further reduced by increasing the efficiency of the spectrograph as much as possible, thus making possible an analysis of a sample of lower total activity. The mass spectrograph described here is an attempt to realize the advantages pointed out above. Particular attention has been given to increasing the increasing the efficiency of the instrument."

Abstract" This is a review, with annotated bibliography, of the mode of occurrence of the element indium. It is not a list of specific ore deposits, but a summary of the types of minerals and rocks in which indium has been reported to occur. In addition, the unpublished spectrographic studies of the Geological Survey on mill and smelter products are summarized, best sources of indium are indicated, and suggestions are made for further investigations. Indium has been found to occur most abundantly in sphalerites. The amount ranges from traces to maximum of 1.0 percent. Dark sphalerites are reported richer in indium than light-colored sphalerites. Up to 0.1 percent indium has been reported in chalcopyrite and bornite, but these minerals generally contain very little indium. There is an unverified report of a pegmatite in Utah containing 1.0 to 2.8 percent indium. Some residues in zinc smelting contain more than 1.0 percent indium and are the present source on indium. No better source can be suggested but steps should be taken to ascertain that this source is being fully exploited. Tin sulfide smelter products should be checked. An effort should be made to check the Utah pegmatite occurrence.