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U.S. Department of Energy
Office of Scientific and Technical Information

Computational support for ITS, ECTOR, PIXY, and PHERMEX. Annual report

Technical Report ·
DOI:https://doi.org/10.2172/510545· OSTI ID:510545
;  [1];  [2]
  1. Mission Research Corp., Albuquerque, NM (United States)
  2. Los Alamos National Lab., NM (United States); and others

This report describes calculations carried out in the past year to assist in the design and understanding of experiments on the ITS, ECTOR, PIXY and PHERMEX machines at LANL. The main results are summarized as follows. ITS: Transport calculations were carried out for Milestone 4, modeling the beam all the way from the cathode surface to the target, and gave good agreement with measurements. The LAMDA transport code was upgraded to compute the focusing effect of the accelerating gaps more accurately, and to remove some approximations in the treatment of space-charge. The code is currently being used in the analysis of the Milestone 5 BBU experiments. ECTOR and PIXY: Beam focusing in the gas cell was studied in detail. The focal length was found to progressively shorten during the pulse. As a result, the minimum spot-size was significantly smaller than the time-averaged value. One may be able to exploit this using shaped converters. The beam distribution at the converter was used as input for the MCNP radiation transport code to obtain a radiographic spot-size. The result agrees reasonably well with experimental data from ECTOR. PHERMEX: The new diode using a flat cathode has almost triple the perveance (current/voltage{sup 3/2}) of the old Pierce diode. The current is somewhat lower than that originally predicted by simulation because the cathode has a small inset from the surrounding electrode. When this effect is included, the calculated current agrees quite well with the experiment.

Research Organization:
Los Alamos National Lab., NM (United States)
Sponsoring Organization:
USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
510545
Report Number(s):
LA-SUB--97-26; ON: DE97008388
Country of Publication:
United States
Language:
English