Positive and negative mesons produced in a common target in the cyclotron are received in two photographic plates. In the magnetic field of the cyclotron, negatives are deflected to one plate, positives to the other. The mesons must pass through an absorber before entering the plates in order to be observable.

Summary: "This report investigates photographic methods of measuring beta radiation and includes a study of temperature effects on these measurements. Experimental data are submitted to show that an increase in film temperature before and during beta irradiation causes a definite increase in density for the same dosage. Recommendations drawn from experience gained in the experimental works are offered."

The thermal decomposition of the higher oxides of praseodymium and americium have been investigated.

The following report discusses the process of several sections of beryllium where 3.018" squares 40" in length can be machined, and six sound 8.0" diameter billets and three trial billets containing casting defects can be extruded.

From abstract: "The present report describes experimental work performed to establish a procedure for the production of uranium metal wire. In all cases, the size of the initial rod was 1/2 inch diameter. Three materials were used: hot extruded tuballoy rod, high purity cast tuballoy rod, and cast U-235 rod."

This report discusses a series of investigations for biological and biochemical study of chronic exposures of animals to neutrons through an irradiation procedure.

Abstract: "The sensitivity to fast neutrons of a CP Meter ionization chamber of the type used for health physics beta and gamma survey measurements has been investigated."

From summary: "Petrographic, X-ray, and analytical studies were made on synthetic and natural zirconium minerals containing varying amounts of hafnium."

This report describes the flow meter for measuring air-flow rate through special hoods that allow the decrease in flow rate.

"The following report is meant to serve a two fold purpose. First, it is the quarterly report of the homogeneous reactor project for the Technical Division of Oak Ridge National Laboratory. Secondly, it is a description and general feasibility discussion of a 200-1000 K.W. pilot model, homogeneous reactor."

Abstract: "A method is described for the identification and quantitative determination of trace amounts of rare earths in graphite by measurement of the energies and decays of the activities induced by neutron irradiation. The specific rare earth elements identified are europium and samarium. During the development of this method, the half-lives of Eu-152 and Sm-153 were determined. These are reported as 9.32 +/- 0.04 hours and 46.34 +/- 0.23 respectively."

In a manner somewhat analogue to that employed by R. Margulies in his memo (BNL Log No. C-2985) on fast source corrections in sigma piles, corrections to be applied to the data obtained on the laid-up graphite in the BNL reactor have been calculated. The correction was computed for a Ra-Be source using the data of Seren and using a standard graphite density for the BNL pile of 1.69. Values of the correction for different experimental sets of data were computed for each of three different diffusion lengths measured parallel to the channels. A correction for diffusion lengths perpendicular to the channels was also determined.

This report analyzes an interspecies (man, dog, rat and mouse) comparison of the radiotoxicities of x-ray, SR-89, and PU-219, based on work done prior to July 1, 1946.

From introduction: "The present report reviews the work conducted on the development of new cements other than magnesium oxychloride during the period from August, 1943, to October 1949. As in the previous reports, the total water contents reported represent the hydrogen combined as water and that which may be combined as a compound other than water."

This report was prepared for a presentation at the London Conference on Raw Materials during September 26-31, 1949, discussing the method of leaching nitrated materials using organic solvents.

Technical report including multiple lectures on nuclear science and engineering, planned to survey the theories, designs, operations, and experimental facilities of the Brookhaven Nuclear Reactor.

The following report provides results taken from a sodium level indicator developed at Sacandaga using electrical resistance as the principle.

This report is a document summarizing all information available on life aspects of various measures proposed to reduce or eliminate corrosion of Van Stone flanger.

The following report summarizes the data taken from a series of measurements on the combustion and ignition properties of hexone. The experiments were taken at the Bureau of Mines Central Experiment Station by their personnel, and the samples were given to them by KAPL and Hanford.

The following report investigates the isolation of the cause of the unusual tool-wear rates found in machining beryllium as attributed to an inherent characteristic of beryllium, or an effect of inclusions in beryllium, as well as the evaluation of the comparative machinability of the various types of beryllium.

From introduction: "The present report covers the results of an extended investigation of magnesium oxychloride cements and concretes. In this study the effects of the composition of the cement or concrete on its physical and mechanical properties were determined. In addition, the stability of the mixes was observed."

"Changes, corrections and additions to the original report are included in this addendum. These are brought about by further development of the design by Blaw-Knox, ANL and ORNL. The changes are listed in accordance with the main headings, pages and paragraphs to which they apply."

"Changes, corrections and additions to the original report are included in this addendum. These are brought about by further development of the design by Blaw-Knox, AHL and ORNL. The changes in the original wiritings are listed below in accordance with the main headings, pages and paragraphs to which they apply. Following this is a list of the contemplated personnel in the MTR program. This listing sets out the number of offices and the office furniture requirements. Also numbers for lockers, showers, toilets and rest rooms are set forth. Although the listing includes all major buildings planned for the site, it is included here since the reactor building wing is more markedly influenced by office requirements."

The following report discusses special shielded containers, called coffins, that are used for removing beam hole plugs from the reactor, transporting them to plug storage and inserting them therein. This report focuses on the handling of dummy and experimental beam hole plugs.