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Effects of the Serber First Step in 3DHZETRN-v2.13DHZETRN-v2 includes a detailed three dimensional (3D) treatment of neutron/light-ion transport based on a quasi-elastic/multiple-production assumption allowing improved agreement of the neutron/light-ion fluence compared with results of three Monte Carlo (MC) codes in the sense that the variance with respect to the individual MC results is less than the variance among the MC code results. The current numerical methods are no longer the main limitation to HZETRN code development and further changes in the nuclear model are required. In a prior study, an improved quasi-elastic spectrum based on a solution of the transport approximation to nuclear media effects showed promise, but the remaining multiple-production spectrum was based on a database derived from the Ranft model that used Bertini multiplicities. In the present paper, we will implement a more complete Serber first step into the 3DHZETRN-v2 code, but we retain the Bertini-Ranft branching ratios and evaporation multiplicities. It is shown that the new Serber model in the 3HZETRN-v2 code reduces the variance with individual MC codes, which are largely due to nuclear cross section model differences.
Document ID
20190031819
Acquisition Source
Langley Research Center
Document Type
Technical Publication (TP)
Authors
Wilson, John W. (Old Dominion Univ. Norfolk, VA, United States)
Werneth, Charles M. (NASA Langley Research Center Hampton, VA, United States)
Slaba, Tony C. (NASA Langley Research Center Hampton, VA, United States)
Badavi, Francis F. (Old Dominion Univ. Norfolk, VA, United States)
Reddell, Brandon D. (NASA Johnson Space Center Houston, TX, United States)
Bahadori, Amir A. (Kansas State Univ. Manhattan, KS, United States)
Sandridge, Christopher A. (NASA Langley Research Center Hampton, VA, United States)
Blattnig, Steve R. (NASA Langley Research Center Hampton, VA, United States)
Norman, Ryan B. (NASA Langley Research Center Hampton, VA, United States)
Date Acquired
September 26, 2019
Publication Date
September 1, 2019
Subject Category
Numerical Analysis
Space Radiation
Report/Patent Number
NF1676L-34294
L-21054
NASA/TP-2019-220401
Distribution Limits
Public
Copyright
Public Use Permitted.

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