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Title: FREYA Developments 2015-2016

Abstract

We have been studying the sensitivity of neutron observables to the FREYA input distributions. Patrick Talou generated 1000 different yield functions, Y(A,Z,TKE), for 252Cf(sf) based on fits to available data on the yields as a function of fragment mass, Y(A), and the total kinetic energy distribution as a function of heavy fragment mass, TKE(AH), and its width, σTKE(AH), to obtain Y(A,TKE). These results are augmented by Wahl systematics to include the fragment charge. We have so far found that the neutron observables do not depend strongly on the yield functions. We also found that the yield functions, constrained by data, are not sufficient to constrain the average neutron multiplicity within the evaluated uncertainty. A paper on this is in progress. We began working on a paper on photofission with the University of Michigan while on a Consortium for Verification Technology fellowship. This is an important paper because they have measured the neutron multiplicity distribution, the prompt fission neutron spectrum, and the energy correlation of two neutrons as a function of angle of separation for the first time in photofission of 235U. We have made FREYA calculations to compare with the data, but the paper is still in progress sincemore » the student left and other researchers have had to take over the analysis. We expect to submit the paper in the next several months, after the analysis is complete.« less

Authors:
 [1]
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  1. Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1335789
Report Number(s):
LLNL-TR-706739
TRN: US1701389
DOE Contract Number:
AC52-07NA27344
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
73 NUCLEAR PHYSICS AND RADIATION PHYSICS; F CODES; FISSION NEUTRONS; PHOTOFISSION; FUNCTIONS; CALIFORNIUM 252; SPONTANEOUS FISSION; FISSION FRAGMENTS; ENERGY SPECTRA; URANIUM 235; YIELDS; KINETIC ENERGY; NEUTRON SPECTRA; DISTRIBUTION; MASS; MULTIPLICITY; CORRELATIONS; SENSITIVITY; PROMPT NEUTRONS

Citation Formats

Vogt, R. FREYA Developments 2015-2016. United States: N. p., 2016. Web. doi:10.2172/1335789.
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Vogt, R. FREYA Developments 2015-2016. United States. doi:10.2172/1335789.
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Vogt, R. Mon . "FREYA Developments 2015-2016". United States. doi:10.2172/1335789. https://www.osti.gov/servlets/purl/1335789.
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@article{osti_1335789,
title = {FREYA Developments 2015-2016},
author = {Vogt, R.},
abstractNote = {We have been studying the sensitivity of neutron observables to the FREYA input distributions. Patrick Talou generated 1000 different yield functions, Y(A,Z,TKE), for 252Cf(sf) based on fits to available data on the yields as a function of fragment mass, Y(A), and the total kinetic energy distribution as a function of heavy fragment mass, TKE(AH), and its width, σTKE(AH), to obtain Y(A,TKE). These results are augmented by Wahl systematics to include the fragment charge. We have so far found that the neutron observables do not depend strongly on the yield functions. We also found that the yield functions, constrained by data, are not sufficient to constrain the average neutron multiplicity within the evaluated uncertainty. A paper on this is in progress. We began working on a paper on photofission with the University of Michigan while on a Consortium for Verification Technology fellowship. This is an important paper because they have measured the neutron multiplicity distribution, the prompt fission neutron spectrum, and the energy correlation of two neutrons as a function of angle of separation for the first time in photofission of 235U. We have made FREYA calculations to compare with the data, but the paper is still in progress since the student left and other researchers have had to take over the analysis. We expect to submit the paper in the next several months, after the analysis is complete.},
doi = {10.2172/1335789},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon Oct 24 00:00:00 EDT 2016},
month = {Mon Oct 24 00:00:00 EDT 2016}
}
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DOI:  10.2172/1335789
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