Accession Number:

ADA636512

Title:

Considerations of Rod-Pinch Diode Operation in Negative Polarity For Radiography

Descriptive Note:

Conference paper

Corporate Author:

NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV

Report Date:

2003-06-01

Pagination or Media Count:

5.0

Abstract:

Negative polarity diode geometries are investigated from 2 - 10 MV with 2D PIC simulations for application to radiography. Rod-pinch RP diodes with non-reentrant blunt tip anodes anode does not pass through a cathode aperture are investigated and compared to self-magnetically-pinched SMP diodes with similar geometries. At lower voltages, reentrant RP geometries are needed so that the space-charge-limited SCL current will exceed the critical current. Once self-pinching is achieved, the electron flow patterns in both types of diodes are similar, but it is speculated that RP diodes will maintain their small spot size for the duration of the pulse. At higher voltage, negative polarity non-reentrant RP designs can take advantage of smaller spot sizes, larger forward-going dose, reduced ion losses, and resistance to gap closure by decoupling the spot from the diode impedance. Reduced ion currents increase the electron current on the high-Z target which could increase the dose by about 40 compared to a positive polarity RP geometry.

Subject Categories:

  • Electrical and Electronic Equipment
  • Operations Research
  • Electricity and Magnetism
  • Nuclear Physics and Elementary Particle Physics

Distribution Statement:

APPROVED FOR PUBLIC RELEASE