“Gamma Meter 1” used at the Nuclear Power Demonstration (NPD) reactor. The hand-held gamma ray monitor, measuring 40 cm in overall length and having a 15 cm long active tube, was apparently used in the Emergency Vehicle at NPD. It was a two-range instrument with both a 0-50 mR/h range and a higher 0-2.5 R/h range. No provision was made to use the counter detecting for beta radiation.
