Initial rough measurements of the quality of the gamma radiation from Co-60 in air indicated agreement with the theoretical calculations of Spencer and Fano for an infinite water medium. Further experiments were performed, duplicating the conditions assumed in the calculations. Since the spectral region between 100 kev and 1 mev has already been examined by Hayward, it was decided to investigate in detail the region below 100 kev and above 1.0 mev. Total radiation dosage measurements were made in water using Victoreen ion chambers. The build-up factor was measured as a function of distance. Good agreement was obtained with the results of White. The spectrum below 150 kev was examined with a small NaI(Tl) scintillation counter and both the shape of the spectrum and the attenuation as a function of distance was in good agreement with the calculations. At distance less than 30 cm from the source the spectral shape changed, gradually broadening with the peak shifting to higher energies. The primary region above 1.0 mev was examined using a large NaI(Tl) crystal, and the gradual loss of resolution in the two primaries as a function of distance with an increase in lower energy events was shown. The measurements to …

This report is the culmination of a year of progress and planning in the high-energy particle field. During this year the Brookhaven Cosmotron has been successfully completed and brought into operation for research at 2.3 Bev. Preliminary experimental results with the copious output of π-mesons are in process of publication. Multiple production of mesons has been observed, a few V-particles detected, and the interactions of π-mesons in hydrogen have been studied. Yet it already appears that higher energies will be needed to produce and study the several new heavy particles detected in cosmic ray observations.

Report issued by the Brookhaven National Laboratory discussing bulk grain irradiators. As stated in the abstract, "this report presents the results of a study to conceive, evaluate, review and estimate costs for a number of suitable designs for a Cobalt-60 Bulk Grain Irradiator; select a preferred type; and establish required criteria for future detail design and construction of the selected concept" (p. ii). This report includes tables, and illustrations.