U. S. NAVAL RADIOLOGICAL DEFENSE LABORATORY SAN FRANCISCO 24, CALIFORNIA i gorse REG: mle AUG 7 4059 Ne dowmgraded to UNCLASSIFIED when separated from enclosure. From: Tos Commanding Officer and Director Department of Defense Agencies on Distribution List for Report Subj: U. S. Naval Radiological Defense Laboratory CONFIDENTIAL RESTRICTED DATA Report USNRDI-TR-1,6; forwarding of Encl: (1) U. S. Naval Radiological Defense Laboratory CONFIDENTIAL RESTRICTED DATA Report USNRDL-TR-1,6 entitled "Spectrometric Analysis of Gamma Radiation from Fallout from Operation REDWING" 1. Enclosure (1) is the fourth in a series of reports dealing with analyses of gamma radiation from fallout samples at various weapons tests. Previous reports were made for Operations UPSHOT-KNOTHOLE (USNRDL-420, 31 August 1953), CASTLE (USNRDL-TR-32, (USNRDL-TR-106, 27 August 1956). 26 January 1955), and TEAPOT 2. Efficient arran;;aments for transportation of samples to the Laboratory allowed analyses to begin as early as 51 hours after shot time — a notable improvement over the earliest-time receipt of four days accomplished at Operation CASTLE, Other improvements have been made in the way of refinements in instrumentation and analyzing techniques. 3. Absolute photon intensities as a function of time are given for each detectable gamma line from each sample, Since the sample constituted an accurately determined portion of the material taken from a fallout col- lector of known area, an estimate can be made of the total gamma source strength per unit area in the vicinity of the collecting site. Dose rates calculated for two samples agree within experimental error with dose rates actually measured at the site. RIC » MANDELK ee