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A flat-cathode thermionic injector for the PHERMEX Radiographic Facility

Conference ·
OSTI ID:6480673
; ; ; ; ;  [1];  [2]
  1. Los Alamos National Lab., NM (United States)
  2. Mission Research Corp., Albuquerque, NM (United States)

The PHERMEX (Pulsed High-Energy Radiographic Machine Emitting X-rays) standing-wave linear accelerator is a high-current electron beam generator used for flash-radiography. An improved electron gun has been designed employing a flat-thermionic cathode to replace the existing Pierce-geometry gun. The flat cathode yields increased current with the same applied voltage and cathode area as the Pierce gun. The ISIS code simulations indicate a beam current of 1.5 kA at 600 kV. The new geometry also reduces the probability for high voltage breakdown in the A-K gap. A reentrant magnet captures the expanding electron beam and a bucking coil nulls cathode-tinge field. A third coil is used to optimize the extraction field profile and reduce the effect of nonlinear space charge on the beam emittance. Time-resolved measurements of beam current and voltage have been made. In addition, a streak camera was used to measure beam emittance and spatial profile. Comparisons of measurements with simulations are presented.

Research Organization:
Los Alamos National Lab., NM (United States); Mission Research Corp., Albuquerque, NM (United States)
Sponsoring Organization:
DOE; USDOE, Washington, DC (United States)
DOE Contract Number:
W-7405-ENG-36
OSTI ID:
6480673
Report Number(s):
LA-UR-93-1715; CONF-930511--104; ON: DE93014584
Country of Publication:
United States
Language:
English