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Investigation of 1-cm dose equivalent for photons behind shielding materials

Technical Report ·
DOI:https://doi.org/10.2172/6148518· OSTI ID:6148518
 [1];  [2]
  1. National Lab. for High Energy Physics, Tsukuba, Ibaraki (Japan)
  2. Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan)

The ambient dose equivalent at 1-cm depth, assumed equivalent to the 1-cm dose equivalent in practical dose estimations behind shielding slabs of water, concrete, iron or lead for normally incident photons having various energies was calculated by using conversion factors for a slab phantom. It was compared with the 1-cm depth dose calculated with the Monte Carlo code EGS4. It was concluded from this comparison that the ambient dose equivalent calculated by using the conversion factors for the ICRU sphere could be used for the evaluation of the 1-cm dose equivalent for the sphere phantom within 20% errors. Average and practical conversion factors are defined as the conversion factors from exposure to ambient dose equivalent in a finite slab or an infinite one, respectively. They were calculated with EGS4 and the discrete ordinates code PALLAS. The exposure calculated with simple estimation procedures such as point kernel methods can be easily converted to ambient dose equivalent by using these conversion factors. The maximum value between 1 and 30 mfp can be adopted as the conversion factor which depends only on material and incident photon energy. This gives the ambient dose equivalent on the safe side. 13 refs., 7 figs., 2 tabs.

Research Organization:
Oak Ridge National Lab., TN (USA)
Sponsoring Organization:
DOE; USDOE, Washington, DC (USA)
DOE Contract Number:
AC05-84OR21400
OSTI ID:
6148518
Report Number(s):
ORNL/TR-90/28; ON: DE91008916
Country of Publication:
United States
Language:
English