Gamma-ray spectra and doses from the Little Boy replica
Most radiation safety guidelines in the nuclear industry are based on the data concerning the survivors of the nuclear explosions at Hiroshima and Nagasaki. Crucial to determining these guidelines is the radiation from the explosions. We have measured gamma-ray pulse-height distributions from an accurate replica of the Little Boy device used at Hiroshima, operated at low power levels near critical. The device was placed outdoors on a stand 4 m from the ground to minimize environmental effects. The power levels were based on a monitor detector calibrated very carefully in independent experiments. High-resolution pulse-height distributions were acquired with a germanium detector to identify the lines and to obtain line intensities. The 7631 to 7645 keV doublet from neutron capture in the heavy steel case was dominant. Low-resolution pulse-height distributions were acquired with bismuth-germanate detectors. We calculated flux spectra from these distributions using accurately measured detector response functions and efficiency curves. We then calculated dose-rate spectra from the flux spectra using a flux-to-dose-rate conversion procedure. The integral of each dose-rate spectrum gave an integral dose rate. The integral doses at 2 m ranged from 0.46 to 1.03 mrem per 10/sup 13/ fissions. The output of the Little Boy replica can be calculated with Monte Carlo codes. Comparison of our experimental spectra, line intensities, and integral doses can be used to verify these calculations at low power levels and give increased confidence to the calculated values from the explosion at Hiroshima. These calculations then can be used to establish better radiation safety guidelines. 7 references, 7 figures, 2 tables.
- Research Organization:
- Los Alamos National Laboratory (LANL), Los Alamos, NM (United States); Technical Programming Services, Pleasanton, CA (USA)
- DOE Contract Number:
- W-7405-ENG-36
- OSTI ID:
- 6813828
- Report Number(s):
- LA-UR-84-1613; CONF-840627-7; ON: DE84012436
- Resource Relation:
- Conference: 29. annual meeting of the Health Physics Society, New Orleans, LA, USA, 3 Jun 1984; Other Information: Portions are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
61 RADIATION PROTECTION AND DOSIMETRY
NUCLEAR WEAPONS
DOSE RATES
GAMMA SPECTRA
EXPERIMENTAL DATA
SPATIAL DISTRIBUTION
DATA
DISTRIBUTION
INFORMATION
NUMERICAL DATA
SPECTRA
WEAPONS
450202* - Explosions & Explosives- Nuclear- Weaponry- (-1989)
655003 - Medical Physics- Dosimetry