skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: An Improved Charged Particle Model in CALEICF

Abstract

Modeling ICF capsules and test problems involving thermonuclear plasmas requires modeling the charged particles produced by the thermonuclear reactions. The charged particles escaping from an ICF capsule are one of the main diagnostics of capsule performance. Caleicf can locally deposit the charged particle energy into the electron and ion fields instantaneously or track them using a Monte Carlo algorithm. Test problems revealed that Caleicf's charged particle package needed improvement. The package has been enhanced to include the thermal energy of the reacting particles and to model the created particles energy distribution. The thermal energy of the reacting particles is accounted for as described in Ballabio, et al. [Ballabio et al., 1998] and Warshaw [Warshaw, 2001] . This energy is removed from the background ion energy and distributed between the created particles. The particle energy distributions are modeled with an approximation used by Ballabio, et al. This distribution is a modified Gaussian (based on the square root of the energy) that has a functional form similar to the exact distribution (see Warshaw). The skewness of the distribution matches that of the exact distribution within 1-2%. The thermal energy and the parameters of the distribution can be calculated using ({sigma}{nu}) and itsmore » first two derivatives with respect to temperature. The new model will be compared with the original one for several test problems and ICF calculations.« less

Authors:
Publication Date:
Research Org.:
Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
900089
Report Number(s):
UCRL-CONF-227316
TRN: US0702163
DOE Contract Number:
W-7405-ENG-48
Resource Type:
Conference
Resource Relation:
Conference: Presented at: Nuclear Explosives Code Developers Conference 2006, Los Alamos, NM, United States, Oct 23 - Oct 27, 2006
Country of Publication:
United States
Language:
English
Subject:
45 MILITARY TECHNOLOGY, WEAPONRY, AND NATIONAL DEFENSE; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; 70 PLASMA PHYSICS AND FUSION TECHNOLOGY; APPROXIMATIONS; ASYMMETRY; CHARGED PARTICLES; DISTRIBUTION; ELECTRONS; ENERGY SPECTRA; FUNCTIONALS; NUCLEAR EXPLOSIVES; PERFORMANCE; SIMULATION; STATISTICS; THERMONUCLEAR REACTIONS

Citation Formats

Managan, R A. An Improved Charged Particle Model in CALEICF. United States: N. p., 2007. Web.
Managan, R A. An Improved Charged Particle Model in CALEICF. United States.
Managan, R A. Wed . "An Improved Charged Particle Model in CALEICF". United States. doi:. https://www.osti.gov/servlets/purl/900089.
@article{osti_900089,
title = {An Improved Charged Particle Model in CALEICF},
author = {Managan, R A},
abstractNote = {Modeling ICF capsules and test problems involving thermonuclear plasmas requires modeling the charged particles produced by the thermonuclear reactions. The charged particles escaping from an ICF capsule are one of the main diagnostics of capsule performance. Caleicf can locally deposit the charged particle energy into the electron and ion fields instantaneously or track them using a Monte Carlo algorithm. Test problems revealed that Caleicf's charged particle package needed improvement. The package has been enhanced to include the thermal energy of the reacting particles and to model the created particles energy distribution. The thermal energy of the reacting particles is accounted for as described in Ballabio, et al. [Ballabio et al., 1998] and Warshaw [Warshaw, 2001] . This energy is removed from the background ion energy and distributed between the created particles. The particle energy distributions are modeled with an approximation used by Ballabio, et al. This distribution is a modified Gaussian (based on the square root of the energy) that has a functional form similar to the exact distribution (see Warshaw). The skewness of the distribution matches that of the exact distribution within 1-2%. The thermal energy and the parameters of the distribution can be calculated using ({sigma}{nu}) and its first two derivatives with respect to temperature. The new model will be compared with the original one for several test problems and ICF calculations.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Wed Jan 10 00:00:00 EST 2007},
month = {Wed Jan 10 00:00:00 EST 2007}
}

Conference:
Other availability
Please see Document Availability for additional information on obtaining the full-text document. Library patrons may search WorldCat to identify libraries that hold this conference proceeding.

Save / Share:
  • As the typical feature size of silicon integrated circuits, such as in VLSI technology, has become smaller, the surface cleanliness of silicon wafers has become more important. Hence, detection of trace impurities introduced during the processing steps is essential. A novel technique, consisting of a ``Charged Particle Energy Filter (CPEF)`` used in the path of the scattered helium ions in the conventional Rutherford Backscattering geometry, is proposed and its merits and limitations are discussed. In this technique, an electric field is applied across a pair of plates placed before the detector so that backscattered particles of only a selected energymore » range go through slits to strike the detector. This can be used to filter out particles from the lighter substrate atoms and thus reduce pulse pileup in the region of the impurity signal. The feasibility of this scheme was studied with silicon wafers implanted with 1{times}10{sup 14} and 1{times}10{sup 13} {sup 54}Fe/cm{sup 2} at an energy of 35 keV, and a 0.5 MeV He{sup +} analysis beam. It was found that the backscattered ion signals from the Si atoms can be reduced by more than three orders of magnitude. This suggests the detection limit for contaminants can be improved by at least two orders of magnitude compared to the conventional Rutherford Backscattering technique. This technique can be incorporated in 200--300 kV ion implanters for monitoring of surface contaminants in samples prior to implantation.« less
  • No abstract prepared.
  • The theory behind track detector response to neutrons is important to the calculation of dose equivalent, and the factors involved in track formation are diverse. We have envisioned a process by which individual parameters important to track interpretation would be identified, quantified, and categorized for use in model development and Monte Carlo calculations to establish dose equivalent algorithms. This paper focuses on just a few of the interactions under investigation in pursuit of empirical model development.
  • Charged-particle transport systems consisting of magnetic quadrupole lenses have been employed in recent years in the study of (n, charged particle) reactions. We have completed a new transport system that is based both on magnetic lenses as well as electrostatic fields. The magnetic focusing of this charged-particle guide is provided by six magnetic quadrupole lenses arranged in a CDCCDC sequence (in the vertical plane). The electrostatic field is produced by a wire at high voltage which stretches the length of the guide and is physically at the center of the magnetic axis. The magnetic lenses are used for charged particlesmore » above 5 MeV; the electrostatic guide is used for lower energies. This hybrid system possesses the excellent focusing and background rejection properties of other magnetic systems. For low energy charged-particles, the electrostatic transport avoids the narrow band-passes in charged-particle energy which are a problem with purely magnetic transport systems. This system is installed at the LLNL Cyclograaff facility for the study of (n, charged particle) reactions at neutron energies up to 35 MeV.« less