X-Ray Dose and Spot Size Calculations for the DARHT-II Distributed Target
The baseline DARHT-II converter target consists of foamed tantalum within a solid-density cylindrical tamper. The baseline design has been modified by D. Ho to further optimize the integrated line density of material in the course of multiple beam pulses. LASNEX simulations of the hydrodynamic expansion of the target have been performed by D. Ho (documented elsewhere). The resulting density profiles have been used as inputs in the MCNP radiation transport code to calculate the X-ray dose and spot size assuming a incoming Gaussian electron beam with {sigma} = 0.65mm, and a PIC-generated beam taking into account the ''swept'' spot emerging from the DARHT-II kicker system. A prerequisite to these calculations is the absorption spectrum of air. In order to obtain this, a separate series of MCNP runs was performed for a set of monoenergetic photon sources, tallying the energy deposited in a volume of air. The forced collision feature was used to improve the statistics since the photon mean free path in air is extremely long at the energies of interest. A sample input file is given below. The resulting data for the MCNP DE and DF cards is shown in the beam-pulse input files, one of which is listed below. Note that the DE and DF cards are entered in column format for easy reading.
- Research Organization:
- Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)
- Sponsoring Organization:
- US Department of Energy (US)
- DOE Contract Number:
- W-7405-ENG-48
- OSTI ID:
- 15005549
- Report Number(s):
- UCRL-ID-145186; TRN: US0305541
- Resource Relation:
- Other Information: PBD: 5 Apr 2001
- Country of Publication:
- United States
- Language:
- English
Similar Records
Hydrodynamic Modeling of a Multi-Pulse X-Ray Converter Target for DARHT - II
Eliminating the Spot Dilution Due to Kicker Switching in DARHT-II