Document Details

OPERATION SUN BEAM, SHOT SMALL BOY, PROJECT OFFICERS REPORT - PROJECT 2.11 - IONIZATION RATE MEASUREMENTS

LARIVIERE, P D; LEE, H [UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATORY]; LARSON, K H [UNIVERSITY OF CALIFORNIA, LOS ANGELES]

Location - DOE/NNSA NUCLEAR TESTING ARCHIVE Address - P.O. Box 98521 City - Las Vegas State - NV Zip - 89193-8521 Phone - (702)794-5106 Fax - (702)862-4240 Email - NTA@NV.DOE.GOV

REPORT

Declassified

0184

NV0051000

POR2217

UNITED STATES NAVAL RADIOLOGICAL DEFENSE LABORATOR

1994 Aug 26

2003 Sep 18

THE BASIC OBJECTIVE OF THIS PROJECT WAS TO MEASURE THE VARIATION WITH TIME OF THE AIR IONIZATION DOSE RATE (R/HR) AND THE CUMULATIVE AIR ION IZATION DOSE (R) DUE TO GAMMA RADIATION 3 FEET ABOVE THE GROUND IN AND ABOUT THE FALLOUT SECTOR OF THE SMALL BOY EVENT. THE ANTICIPATED FAL LOUT SECTOR WAS INSTRUMENTED WITH 140 GAMMA INTENSITY VERSUS TIME RECO RDERS (GITR). HIGH RANGE GITR'S CAPABLE OF REGISTERING UP TO 80,000 R/ HR WERE USED AT CLOSE-IN STATIONS. LOW RANGE GITR'S CAPABLE OF REGIST ERING DOWN TO 1 MR/HR WERE USED AT REMOTE STATIONS. SUPPORT AND BACK- UP DATA WERE SUPPLIED BY DOSIMETERS AND REMOTE READING RADIACS, AS WEL L AS PROJECT 2.8 GAMMA SURVEYS AND FILM DOSIMETRY. THE FALLOUT PATH W AS CENTRALLY ORIENTED WITHIN THE PROJECT 2.11 STATIONARY INSTRUMENTATI ON ARRAY THAT EXTENDED TO A NORTH-SOUTH LINE 20 MILES LONG, LOCATED 16 -1/2 MILES EAST OF SURFACE ZERO. AT THIS LINE, 14 OF 24 GITR STATIONS RECORDED THE RADIATION EVENT PRODUCED BY FALLOUT. AT CLOSER LOCATION S (APPROXIMATELY 1 TO APPROXIMATELY 9 MILES) 45 OF 72 GITR'S RECORDED THE INITIAL RADIATION, OR THE FALLOUT RADIATION EVENT, OR BOTH, WITHIN THE LIMITATION OF THE INSTRUMENTS. NINE INSTRUMENTS WITHIN THE AREA OF SIGNIFICANT FALLOUT RADIATION WERE INOPERATIVE AND FAILED TO RECORD THE RADIATION EVENT AT THEIR LOCATIONS. AT REMOTE REGIONS (16-1/2 TO 200 MILES FROM SURFACE ZERO) WHERE MOBILE TEAMS WERE RELIED UPON TO P LACE 40 GITR'S IN THE PREDICTED FALLOUT PATH, IT WAS ALMOST IMPOSSIBLE TO IDENTIFY THE PATH OF CLOUD MOVEMENT FROM THE WIND DATA AVAILABLE D URING THE FIRST SEVERAL HOURS FOLLOWING DETONATION; CONSEQUENTLY, ONLY EIGHT OF THE UNITS PLACED RECORDED SIGNIFICANT RADIATION FIELDS. THE AIR IONIZATION DOSE RATE VARIATION WITH TIME WAS THOROUGHLY DOCUMENTED . THE DOSE RATE HISTORIES RECORDED AT THE 59 STATIONARY GITR STATIONS ARE PRESENTED GRAPHICALLY AND IN TABULAR FORM. DOSE ACCUMULATIONS WI TH TIME ARE PRESENTED GRAPHICALLY FOR GITR STATIONS LOCATED CENTRALLY IN THE FALLOUT PATH AND IN TABULAR FORM FOR ALL 59 GITR STATIONS. THE DOSE RATE HISTORIES OF THE EIGHT REMOTELY PLACED GITR'S ARE PRESENTED IN TABULAR FORM; SIX OF THESE ARE ALSO PRESENTED GRAPHICALLY. INITIA L GAMMA DOSES (0 TO 1 MINUTE) WERE ESTIMATED FROM THE RECORDED DATA AN D FOUND TO VARY FROM 86 R AT 4,00 FEET TO LESS THAN 1 MILLIROENTGEN AT DISTANCES GREATER THAN 14,000 FEET. TRANSIT DOSES AS WELL AS STANDAR D RADIATION DOSE RATES WERE TENTATIVELY ESTIMATED. THE EFFECT OF WEAT HERING IN REDUCING THE DOSE RATE WAS SMALL COMPARED TO THE REDUCTION F ROM RADIOACTIVE DECAY.