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.

We have recently completed measurement of resonance escape probability in the BNL reactor and in several slightly-enriched uranium light water moderated lattices. In addition, WAPD has made available to us data from other slightly enriched uranium-water lattices, so that about 18 lattices in all have been done.

Report issued by the Brookhaven National Laboratory discussing data collected from two BNL meteorological towers. As stated in the introduction, "results are presented in graphic form rather than tabular form" (p. 1). This report includes tables, maps, illustrations, and photographs.

Two methods for measuring target efficiencies are briefly discussed. The second method puts an upper bound on the efficiency and permits observation of instantaneous efficiency, thereby aiding location of losses. Measurements agree well with conventional radiochemical values.

The studies of Irving and Edgington, and Healy on the synergistic effects of tributyl phosphate (TBP) and tri-n-octylphosphine oxide (TOPO) on the solvent extraction of thorium and other metals by thenoyltrifluoroacetone (TTA) are discussed. It is shown that the synergistic effect is a result of addition reactions as well as replacement reactions and is not a function of the metal being extracted. A compilation of equilibrium constants describing the synergistic effect of TBP and TOPO on TTA extraction is given for the following metal ions: Th4+, UO2,2+, Am2+, Cm3+, Pm3+, Tm3+, and Ca2+.

A circuit is described developed to fill the need for a pulser with a 15-20 volt amplitude into the 93 ohm line, stable, transistorized and low cost, fast 10 Nano second rise, and a variable repetition period from 0.5 sec. to 4 sec.

A short review of the field of internal conversions. Isomeric transitions teach us many details of nuclear structure. In these studies electromagnetic theory is considered as a "tool". It is a quite quantitative tool in the case of "internal conversion" - a phenomenon which has been widely studied for many years. Internal conversion takes place in competition with γ-ray emission: a fraction of the nuclei in excited states decay by γ-ray emission, the remaining fraction by transferring the energy to K, or L, etc. electrons in the atomic shell. Thus the lifetime of an excited nuclear state depends on the internal conversion coefficient. As internal conversion must be expected to depend on the details of the electronic environment, the lifetime of an isomeric state depends on the state of chemical combination of the isomer - as was recently shown explicitly in one case, that of Te-99m(6hr.).