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Title: Modeling blur in various detector geometries relevant to DARHT

Authors:
 [1];  [1];  [1]
  1. Los Alamos National Laboratory
Publication Date:
Research Org.:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1352435
Report Number(s):
LA-UR-17-23188
DOE Contract Number:
AC52-06NA25396
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English

Citation Formats

Winch, Nicola M., Watson, Scott Avery, and Hunter, James F. Modeling blur in various detector geometries relevant to DARHT. United States: N. p., 2017. Web. doi:10.2172/1352435.
Winch, Nicola M., Watson, Scott Avery, & Hunter, James F. Modeling blur in various detector geometries relevant to DARHT. United States. doi:10.2172/1352435.
Winch, Nicola M., Watson, Scott Avery, and Hunter, James F. 2017. "Modeling blur in various detector geometries relevant to DARHT". United States. doi:10.2172/1352435. https://www.osti.gov/servlets/purl/1352435.
@article{osti_1352435,
title = {Modeling blur in various detector geometries relevant to DARHT},
author = {Winch, Nicola M. and Watson, Scott Avery and Hunter, James F.},
abstractNote = {},
doi = {10.2172/1352435},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2017,
month = 9
}

Technical Report:

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  • Investigates the optimization of light capture efficiency in a two scintillation cell radiation detector
  • This report describes the US Stockpile Stewardship Program which is meant to sustain and evaluate nuclear weapon stockpile with no underground nuclear tests. This research will focus on DARHT, the Dual Axis Radiographic Hydrodynamic Test facility.
  • The U.S. Stockpile Stewardship Program [1] is designed to sustain and evaluate the nuclear weapons stockpile while foregoing underground nuclear tests. The maintenance of a smaller, aging U.S. nuclear weapons stockpile without underground testing requires complex computer calculations [14]. These calculations in turn need to be verified and benchmarked [14]. A wide range of research facilities have been used to test and evaluate nuclear weapons while respecting the Comprehensive Nuclear Test-Ban Treaty (CTBT) [2]. Some of these facilities include the National Ignition Facility (NIF) at Lawrence Livermore National Laboratory, the Z machine at Sandia National Laboratories, and the Dual Axismore » Radiographic Hydrodynamic Test (DARHT) facility at Los Alamos National Laboratory. This research will focus largely on DARHT (although some information from Cygnus and the Los Alamos Microtron may be used in this research) by modeling it and comparing to experimental data. DARHT is an electron accelerator that employs high-energy flash x-ray sources for imaging hydro-tests. This research proposes to address some of the issues crucial to understanding DARHT Axis II and the analysis of the radiographic images produced. Primarily, the nature of scatter at DARHT will be modeled and verified with experimental data. It will then be shown that certain design decisions can be made to optimize the scatter field for hydrotest experiments. Spectral effects will be briefly explored to determine if there is any considerable effect on the density reconstruction caused by changes in the energy spectrum caused by target changes. Finally, a generalized scatter model will be made using results from MCNP that can be convolved with the direct transmission of an object to simulate the scatter of that object at the detector plane. The region in which with this scatter model is appropriate will be explored.« less
  • An investigation was carried out on the effects of different cathode shroud geometries of the DARHT Axis-1 diode using the Trak ray tracing software. Pierce angles of 20, 30, 45, 60, and 67.5 degrees were investigated. For each geometry the current density with respect to radial position will be presented as it evolves in the longitudinal direction. In addition the emittances for each geometry are compared and this information is used to determine the optimal geometry from the selected angles. These results are compared to the baseline geometry currently employed at DARHT of a simple 2.5mm recessed velvet cathode. Ofmore » the selected angles it was found that 45 degrees produced the lowest normalized emittance value, whereas 60 degrees produced the most uniform current density profile at 1cm away from the emission surface. For the purpose of this investigation the effects of the bucking coil and solenoid around the hollow anode of the DARHT Axis I injector are neglected.« less