This monthly report details Physics Department 100 Area technical activities for the month of April 1947.

None

In order to further understand the nature of changes which occur in the fingers of persons occupationally exposed to radiation a series of experiments were performed on human subjects generally using x-rays at 130 KV potential, 20 ma and at a distance of 10 cm. Doses ranged from 200-600 r. Fourteen subjects were patients being treated by x-rays or radium for other purposes. The other subject was a staff member who occasionally prepared radium plaques containing 130 mgm of radium. Counts were made of the number of vessels in the terminal row of a measured area of the nail fold. In no case was there any detectable change in the nail fold area within 15 minutes of treatment. Observations were continued for up to 56 days and changes observed included hyperemia, pigmentation, erythemia, and some transitory changes in vascular structure of the affected area. A recommendation for continued studies is made.

This technical progress letter contains reports from six Technical Department divisions at the Hanford Engineer Works for February 9, through February 15, 1947. The six reporting divisions are: 100 Areas, 300 Area, 200 Areas, Chemical Development, Laboratories, and Statistical Studies.