Skyshine at neutron energies less than or equal to 400 MeV
The dose equivalent at an air-ground interface as a function of distance from an assumed azimuthally symmetric point source of neutrons can be calculated as a double integral. The integration is over the source strength as a function of energy and polar angle weighted by an importance function that depends on the source variables and on the distance from the source to the filed point. The neutron importance function for a source 15 m above the ground emitting only into the upper hemisphere has been calculated using the two-dimensional discrete ordinates code, DOT, and the first collision source code, GRTUNCL, in the adjoint mode. This importance function is presented for neutron energies less than or equal to 400 MeV, for source cosine intervals of 1 to .8, .8 to .6 to .4, .4 to .2 and .2 to 0, and for various distances from the source to the field point. As part of the adjoint calculations a photon importance function is also obtained. This importance function for photon energies less than or equal to 14 MEV and for various source cosine intervals and source-to-field point distances is also presented. These importance functions may be used to obtain skyshine dose equivalent estimates for any known source energy-angle distribution.
- Research Organization:
- Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
- DOE Contract Number:
- W-7405-ENG-26
- OSTI ID:
- 6923947
- Report Number(s):
- ORNL/TM-7512; TRN: 80-019655
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NEUTRON DOSIMETRY
BACKSCATTERING
NEUTRON IMPORTANCE FUNCTION
AIR
BROOKHAVEN AGS
COMPUTER CALCULATIONS
ISABELLE STORAGE RINGS
MEV RANGE 100-1000
SPATIAL DOSE DISTRIBUTIONS
TWO-DIMENSIONAL CALCULATIONS
ACCELERATORS
CYCLIC ACCELERATORS
DOSIMETRY
ENERGY RANGE
FLUIDS
FUNCTIONS
GASES
MEV RANGE
RADIATION DOSE DISTRIBUTIONS
SCATTERING
STORAGE RINGS
SYNCHROTRONS
654003* - Radiation & Shielding Physics- Neutron Interactions with Matter