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Proceedings Paper

Intense nanosecond duration source of x rays for resolving cavitation-induced trauma in human tissue
Author(s): Craig Nelson Boyer; Glenn E. Holland; John F. Seely
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Paper Abstract

A pulsed nanosecond x-ray generator based on an actively pumped field emission x-ray tube is described. The x-ray source is based on a high voltage Marx generator that drives a field emission tube without the need for an intermediate energy store. The Marx generator stores 12 Joules in ceramic capacitors and produces a voltage pulse > 380 kilovolts with a rise time of < 4 nanoseconds from an equivalent generator-impedance of 52 W. A numerical model is used in which the x-ray tube's cathode width and anode-cathode gap (AK) are permitted to change with time while electron current between the cathode and anode is treated as non relativistic and space-charge-limited (SCL). By coupling this model to an equivalent circuit representation of the Marx generator a calculation of the cathode current, anode-cathode potential and the output x-ray spectrum can be made. The radiation dose is 55 millirems at 30.4 cm from the anode of the x-ray tube and is Gaussian in shape with a 35 nanosecond (full width at half maximum) FWHM. The measured x-ray dose, pulse shape and width are consistent with model predictions. The source was successfully used to study high-velocity projectile induced cavatation in human tissue.

Paper Details

Date Published: 3 November 2004
PDF: 12 pages
Proc. SPIE 5537, X-Ray Sources and Optics, (3 November 2004); doi: 10.1117/12.558797
Show Author Affiliations
Craig Nelson Boyer, Praxis Inc. (United States)
Glenn E. Holland, Sachs Freeman Associates (United States)
John F. Seely, Naval Research Lab. (United States)

Published in SPIE Proceedings Vol. 5537:
X-Ray Sources and Optics
Carolyn A. MacDonald; Albert T. Macrander; Tetsuya Ishikawa; Christian Morawe; James L. Wood, Editor(s)

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