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Title:
REPORT TO THE TEST DIRECTOR, OPERATION UPSHOT-KNOTHOLE, NEVADA PROVING GROUNDS, MARCH - JUNE 1953, PROJECT 29.4, EFFECTIVE ENERGY OF RESIDUAL GAMMA RADIATION
Author(s):
Subject Terms:
INTERNAL IRRADIATION; SPATIAL DOSE DISTRIBUTIONS; UPSHOT OPERATION; GAMMA RADIATION; UPSHOT-KNOTHOLE OPERATION
Document Location:
Location - NNSA/NSO 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 - CIC@NV.DOE.GOV
Document Type:
REPORT
Publication Date:
1953 Mar 31
Declassification Status:
Declassified
Document Pages:
0072
Accession Number:
NV0006243
Document Number(s):
WT814
Originating Research Org.:
University of Rochester
OpenNet Entry Date:
1994 Aug 26
Description/Abstract:
EVALUATION OF THE GAMMA-RAY QUALITY OF THE RESIDUAL RADIATION FOLLOWIN G AN INSTANTANEOUS FISSION REACTION IS NECESSARY FOR ESTABLISHING DESI GN REQUIREMENTS OF RADIATION-DETECTION INSTRUMENTS USED IN PERSONNEL M ONITORING. A THEORETICAL STUDY OF THE GAMMA-RAY SPECTRUM FROM FISSION PRODUCTS IS DESCRIBED AS A FUNCTION OF TIME FROM THE FISSION REACTION . THE ENERGY FLUX OF PHOTONS WITH ENERGY BELOW 0.2 MEV INCREASES RELA TIVE TO THAT OF PHOTONS WITH HIGHER ENERGIES AS THE TIME FROM FISSION REACTION INCREASES UP TO SEVEN DAYS. THIS INCREASED RELATIVE FLUX OF PHOTONS WITH ENERGIES BELOW 0.2 MEV, TOGETHER WITH A SLIGHT GENERAL DE CREASE OF PHOTON ENERGIES DUE TO COMPTON SCATTERING IN THE AIR, CAN AC COUNT FOR THE RELATIVE VARIATION OF READINGS FROM ENERGY-DEPENDENT DET ECTORS WHICH WERE USED IN THE FIELD STUDIES. FIELD MEASUREMENTS WERE OBTAINED WITH ENERGY-DEPENDENT IONIZATION CHAMBERS, DEPTH-DOSE CURVES IN A PHANTOM MAN, AND PHOTOGRAPHIC ABSORPTION CURVES MADE WITH COPPER SPHERES. THESE FIELD MEASUREMENTS SHOWED THE PRESENCE OF A WIDE RANGE OF PHOTON ENERGIES FROM AROUND 60 KEV TO ABOVE 600 KEV. UNIT-DENSITY ABSORBERS WERE FOUND TO BE UNRELIABLE AS EFFECTIVE-ENERGY-MEASURING D EVICES IN THE FIELD STUDIES. FIELD-EQUIVALENT X-RAY BEAM MIXTURES WER E DETERMINED IN THE LABORATORY FROM THE FIELD DATA EMPLOYING COMMONLY USED X-RAY BEAMS. THESE INDICATED THAT THE LOW-PHOTON-ENERGY RESPONSE OF PERSONNEL-RADIATION-MONITORING INSTRUMENTS SHOULD BE CHECKED IN AN X-RAY BEAM MIXTURE EQUIVALENT TO 30 ROENTGEN PARTS OF 200-KVP RAYS WI TH NO FILTER AND 70 ROENTGEN PARTS OF 1000-KVP X RAYS WITH NO FILTER. RADIUM GAMMA RAYS OR HEAVILY FILTERED 1000-KVP X RAYS SHOULD BE USED FOR THE HIGH-PHOTON-ENERGY RESPONSE. HIGH-ENERGY BETA PARTICLES WERE FOUND TO PRODUCE READING ON GAMMA-RAY-MEASURING INSTRUMENTS IN FALL-OU T AREAS. A BETA-PARTICLE SHIELD EQUIVALENT TO APPROXIMATELY 750 MILLI GRAMS/CENTIMETERS SQUARED OF PLASTIC SHOULD BE PLACED AROUND THE DETEC TOR COMPONENT OF INSTRUMENTS DESIGNED TO DETECT GAMMA RADIATION ONLY.


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