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

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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.

Author(s):
Cooperstein, G. ; Swanekamp, S. B. ; Schumer, J. W. ; Ottinger, P. F. ; Commisso, R. J.
Author Organization(s):
NAVAL RESEARCH LAB WASHINGTON DC PLASMA PHYSICS DIV
Descriptive Note:
Conference paper
Supplementary Note:
Prepared in collaborarion with Titan-JAYCOR Division, McLean, VA. Presented at 2003 IEEE Pulsed Power Conference (14th), PPC-2003, in Dallas, TX on 15-18 Jun 2003 and published in proceedings of the same, p975-978; 0-7803-7915-2/03. See also ADM002371, 2013 IEEE Pulsed Power Conference, Digest of Technical Papers 1976-2013, and Abstracts of the 2013 IEEE International Conference on Plasma Science. The original document contains color images.
Pagination:
0005

Security Markings

DOCUMENT & CONTEXTUAL SUMMARY

Distribution:
Approved For Public Release
Distribution Statement:
Approved For Public Release; Distribution Is Unlimited.

RECORD

Collection: TR
Identifying Numbers
Monitor Series:
DOE
 Subject Terms
Joint Capability Areas:
JCA_3.2_Engagement; JCA_3_Force Application; JCA_1.2.7_Experimentation; JCA_3.2.2_Non-Kinetic Means; JCA_8_Building Partnerships
Communities of Interest:
Energy and Power Technologies
Descriptor(s):
*RADIOGRAPHY, COMPARISON, DIODES(ELECTRON TUBES)
Field(s)/Group(s):
Electrical and Electronic Equipment, Operations Research, Electricity and Magnetism, Nuclear Physics and Elementary Particle Physics
Keyword(s):
ROD PINCH DIODES, SELF MAGNETICALLY PINCHED DIODES, NEGATIVE POLARITY, ELECTRON FLOW PATTERNS
Report Date:
2003 Jun 01
Creation Date:
2016 Sep 07