18 to facilitate draining and decontaminating the interior. 6. Shock-mount the probe with at least one inch of sponge rubber. 7. Add range scales to the control unit with the follow- ing ranges: 5, 30, 50, 300, Gamma Ray Spectra. 500, and 3000 microroentgens. Plankton sample 9D was first analyzed, unashed, on June 22, ashed and analyzed on June 23, and allowed to decay until July 2, when it was again analyzed. The results are shown in Table 4. Both the gamma peaks for 1131 (.32 and .66 Mev) and Ru!3 (.23 Mev) exhibited marked reduction in intensity after ashing. The I 131 peak, accounting for most of the iodine activity (.32 Mev, 85 per cent), had Gisappeared by July 2. The gamma spectrum curves give good indications for the presence of Mo?? s Ry) J of zr?? and Ce 141 zi31 Bal 40 and Lalo, The presence is questionable. eyaey