Generating Soft X-Ray Spectra Using the SPEED Pentaxial Diode

摘要

At 70 kV charge voltage and three anode-cathode (A-K) gaps, 2.0, 2.5, and 3.0 mm, SPEED and the pentaxial diode provide bremsstrahlung-x-ray exposures with peak electron voltages of 350 +- 60, 490 +- 50, and 590 +- 50 kV. At these voltages, the pentax delivers peak dose rates of 0.16 +- 0.06, 0.33 +- 0.08, and 0.57 +- 0.10 . 10 sup 12 rad(CaF sub 2 )/s, respectively. The 4.4 cm radius opening in a steel clamp ring defines the high-exposure area of 60 cm sup 2 , 2.1 cm from the tantalum converter. The peak dose occurs at a radius of 1.9 cm, with the axial dose reaching about 80% of the peak. The dose falls to about 70% of peak at 3.8 cm radius. We used the normal pentaxial diode hardware and charged the SPEED Marx generator to 70 kV instead of the normal 90 or 95 kV. A 30 cm diameter and 30 cm deep re-entrant bellows on the vacuum chamber contains the exposure area and maintains a normal atmosphere around the test object. Thermoluminescent dosimeters (TLDs) measured the dose to CaF sub 2 , and silicon PIN diodes measured the radiation pulse width. (ERA citation 12:046061)