This report describes the optical analogue that contains an optical filtering system which controls the intensity of light according to the assumed initial distribution of activity over height and particle size and according to the assumed decay rate, a size control system which depends on the lateral dimensions of the cloud of debris and adjusts the size of the light beam accordingly, and a position control system which moves the beam to the correct position on the plate as determined by the wind structure and the time of fall of the particles.

The following report describes the high pressure and temperature homogeneous reactor experiment which has been started at Los Alamos, as well as the hazards and safety aspects for the experiments.

"This report contains information on the following topics related to the radiation shielding at test cell "C". (1) Calculation of wall and roof thicknesses. (2) Calculation of radiation heating of front wall by gamma and neutron absorption. (3) Calculation of neutron activation in front face of test cell. (4) Calculation of γ-dose rates both direct and behind shadow shields at various distances. (5) Dose produced by a reactor catastrophe."

This technical report describes the preparation and properties of plastic bonded RDX mixtures containing approximately 30 weight percent RDX. These mixtures may readily be prepared by a method adaptable to existing ordnance plant equipment. they are roughly comparable to Compositions A and B in sensitivity and explosive performance, but are much stranger physically than these or similar explosives.

Final report describing the development and usage of an automatic decade scaler which operates for a fixed number of counts, developed for use with a Geiger tube.

The two plutonium-metal critical assemblies that have been studied at Pajarito Site are Jezebel, bare plutonium; and Popsy, a plutonium core in a thick normal uranium reflector. These assemblies and their properties are described.

Diagrams provided for a convenient overview and standardized framework of the United States transportation system.

A method using photographic emulsions for the study of neutron distributions is described. The construction of a simple machine for producing experimental critical assemblies in which the method has been used is reported. Sources of error are discussed. Curves of the perturbations when small spheres of various materials are placed in the center of the assembly are shown.

The work of the Laboratory has greatly expanded into applications of nuclear energy which are significant for national defense and security, but are not directly connected with weapons development. It was felt, therefore, that a description of the non weapons activities of the Laboratory would serve a useful purpose at this time. For classification reasons, it has been necessary to issue the report in three parts; the third part concerns power reactor experiments.

Certain oralloy (Oy) lattices were immersed in infinite water for determining critical masses at various low-Oy densities. Three Oy unit sizes were used. In a broad sense the experiment shows safe and unsafe conditions for handling heterogeneous Oy-water mixtures.

From foreword: Evaluation of the experimental data on the light isotopes, hydrogen through beryllium, was initiated by LASL in mid-1963. Since the data compilations available were completely inadequate for the task at hand, the tedious program of compiling and plotting was undertaken. As the work progressed an attempt was made to eliminate many of the obvious errors and inconsistencies found in the literature and existing compilations.

A technique for the fusion welding of uranium has been under development and several methods of fusion welding have been investigated. The inert gas, shield arc method has proven to be the most satisfactory of the processes thus far examined. Uranium properly weld by this method was free from porosity, cracks, and oxide inclusions. Certain precautions and some special techniques were required to make good welds.

Preface: This report contains data and information on the resurvey effort and the effect of residual contamination as a result of nuclear weapons development programs conducted in this area.

A glass vacuum manifold and ionization chamber are evacuated and filled to atmospheric pressure with hydrogen and tritium. The hydrogen and tritium are evolved by dropping liquid, urine or water, on calcium metal and dried by passing through a suitable freezing bath. The current produced by the beta activity due to tritium is measured with a vibrating reed electrometer. The method has a precision of +3 per cent between the ranges of 100 and 1500 pc of tritium per liter. From O to 100 pc of tritium per liter the precision is +-5 to 10 per cent. The glass vacuum manifold has been constructed to fit in an aluminum suitcase which contains all the auxiliary equipment for the determination except the vacuum pump, vibrating reed electrometer, and the freezing bath solutions. The apparatus is sturdy and readily transported. The procedure is simple and adapted for use by untrained personnel.

Bibliography of unclassified work published by the Los Alamos Scientific Laboratory during 1972-1976. This volume contains listings of publications, organized by topic, with title, author, and citation information.

Supplementary data containing a keyword-in-context index to accompany a report on the Los Alamos Scientific Laboratory research publications.