The Development of a Neutron Evaporation Theory Code for the Thermal Fission of Uranium-235

reportActive / Technical Report | Accession Number: ADA156593 | Open PDF

Abstract:

The thermal fission of Uranium-235 has been studied by developing a computer code that used evaporation theory based on the Weisskopf model for neutron emission from individual fission fragments. This computer code calculates a prompt neutron spectrum for the thermal fission of Uranium-235, calculates the total gamma ray energy for the fission of Uranium-235, and calculates the average prompt neutron kinetic energy. Until now, evaporation theory codes used average values of mass and energy in determining prompt neutron spectra, and this code was developed to use all possible fission fragment combinations in order to eliminate this averaging. This approach is necessary to compute certain measured data such as the probability that 0,1,2,.. . neutrons are emitted per fission. This code uses subroutines to calculate rest masses, corrects the calculated rest mass to agree with experiment, and to determine the emitted neutron kinetic energies. Evaporation theory codes have predicted low total gamma energy release in fission, but agree quite favorably with experiments in predicting the average prompt neutron kinetic energy. The prompt neutron spectrum obtained in this code has a high tail region, that is, below 0.5 MeV. The average kinetic energy of the neutrons agree very well with experiment, and the total gamma energy is lower than experiment, as previous evaporation theory codes have been. Keywords Fission Prompt neutron spectrum Uranium-235, Liquid drop model Semi-empirical mass formula. Theses

Author(s):
Rosener, Thomas J.
Author Organization(s):
ARMY MILITARY PERSONNEL CENTER ALEXANDRIA VA
Descriptive Note:
Final rept.
Supplementary Note:
Master's thesis.
Pagination:
0115

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release
Distribution Statement:
Approved For Public Release; Distribution Is Unlimited.

RECORD

Collection: TR
Identifying Numbers
Monitor Series:
MILPERCEN
 Subject Terms
Joint Capability Areas:
JCA_3.2_Engagement; JCA_3_Force Application; JCA_3.2.1_Kinetic Means; JCA_6.3.3_Spectrum Management; JCA_6.3_Net Management; JCA_6_Net Centric; JCA_1.2.7_Experimentation; JCA_1_Force Support; JCA_5_Command and Control; JCA_4.5.4_Requirements Definition; JCA_4.5_Operational Contract Support; JCA_5.3_Planning; JCA_1.2.5_Lessons Learned; JCA_1.2_Force Preparation; JCA_1.3_Human Capital Management; JCA_1.4.2_Health Service Delivery; JCA_1.4_Force Support
Modernization Areas:
Microelectronics; Quantum Science and Computing
Communities of Interest:
No COI(s) Identified
Descriptor(s):
*COMPUTER PROGRAMS, *NEUTRON SPECTRUM, *PROMPT NEUTRONS, *URANIUM, CODING, EMISSION, ENERGY, ENERGY TRANSFER, EVAPORATION, FISSION, FISSION PRODUCTS, FORMULATIONS, GAMMA EMISSION, GAMMA RAYS, KINETIC ENERGY, MASS, NUCLEAR ENERGY, NUCLEAR MODELS, RADIOACTIVE ISOTOPES, REST, SUBROUTINES, THEORY, THESES
Field(s)/Group(s):
Nuclear Physics and Elementary Particle Physics
Keyword(s):
URANIUM 235, WEISSKOPF MODEL, EVAPORATION THEORY CODES, LIQUID DROP MODELS
Report Date:
1985 May 03