Plasma-Filled Diode for High Dose-Rate Bremsstrahlung
Abstract
A plasma-filled diode (PFD) can produce high dose-rate (>2 1012 rad/s) bremsstrahlung over small areas (100 cm2) on the Saturn generator at Sandia. A PFD was developed for this purpose using the Gamble II generator at NRL. The maximum dose-rate was obtained with a conduction time of 40 ns, after which the voltage increased to 1.8 MV and the total current in the diode was 0.5 MA. The 3.6-Ohm maximum impedance is the same as for a hypothetical vacuum diode with an AK gap of 0.6 mm. The x-ray pulse width (FWHM) was 8 ns, much less than the typical 50 ns FWHM with a vacuum diode. This PFD was adapted to the higher-current (6-8 MA) Saturn generator by making a 10-cm diameter circular array of 6- 12 isolated PFDs. Higher dose rates were obtained using fewer PFDs; about 1 1012 rad/s with the 12-PFD array, 2 1012 with 9 PFDs and 4 1012 with 6 PFDs. Analyses based on electrical and radiation diagnostics indicate that 40-75% of the electrical current produces radiation at the time of maximum dose rate. The x-ray pulse width was typically 12-15 ns, about half of the pulse width for standard (vacuum) bremsstrahlung diodes on Saturn. This system, with improvements in reproducibility at high dose rate, could provide a high dose-rate, small-area testing capability for Saturn.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jun 01, 2003
- Accession Number
- ADA636162
Entities
People
- Bruce V. Weber
- David D. Hinshelwood
- Donald P. Murphy
- Stavros J. Stephanakis
Organizations
- United States Naval Research Laboratory