Rod pinch diodes have shown considerable capability as high-brightness flash x-ray sources for penetrating dynamic radiography. The rod pinch diode uses a small diameter (0.4–2 mm) anode rod extended through a cathode aperture. When properly configured, the electron beam born off of the aperture edge can self-insulate and pinch onto the tip of the rod creating an intense, small x-ray source. Sandia’s SABRE accelerator (2.3 MV, 40 Ω, 70 ns) has been utilized to optimize the source experimentally by maximizing the figure of merit (dose/spot diameter2) and minimizing the diode impedance droop. Many diode parameters have been examined including rod diameter, rod length, rod material, cathode aperture diameter, cathode thickness, power flow gap, vacuum quality, and severity of rod–cathode misalignment. The configuration producing the greatest figure of merit uses a 0.5 mm diameter gold rod, a 6 mm rod extension beyond the cathode aperture (diameter=8 mm), and a 10 cm power flow gap to produce up to 3.5 rad (filtered dose) at 1 m from a 0.85 mm x-ray on-axis spot (1.02 mm at 3° off axis). The resultant survey of parameter space has elucidated several physics issues that are discussed.

1.
G.
Cooperstein
,
J. R.
Boller
,
R. J.
Commisso
,
D. D.
Hinshelwood
,
D.
Mosher
,
P. F.
Ottinger
,
J. W.
Schumer
,
S. J.
Stephanakis
,
S. B.
Swanekamp
,
B. V.
Weber
, and
F. C.
Young
,
Phys. Plasmas
8
,
4618
(
2001
).
2.
R. A.
Mahaffey
,
J.
Golden
,
S. A.
Goldstein
, and
G.
Cooperstein
,
Appl. Phys. Lett.
33
,
795
(
1978
).
3.
P. R. Menge, J. Gustwiller, D. L. Johnson, J. E. Maenchen, I. Molina, D. C. Rovang, R. Shear, S. Cordova, D. Droemer, E. Hunt, E. Ormand, L. Woo, R. J. Commisso, G. Cooperstein, S. B. Swanekamp, B. V. Oliver, D. V. Rose, and D. R. Welch, in Conference Records—Abstracts, 2000 IEEE International Conference on Plasma Science, New Orleans, Louisiana, 4–7 June, 2000 (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 2000), IEEE Catalog No. 00CH37087, p. 232.
4.
J. P. Corley, J. A. Alexander, P. J. Pankuch, C. E. Heath, D. L. Johnson, J. J. Ramirez, and G. J. Denison, in Proceedings of the 8th IEEE International Pulsed Power Conference, San Diego, California, 16–19 June, 1991, edited by R. White and K. Prestwich (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 1991), IEEE Catalog No. 91CH3052-8, p. 920.
5.
J. J. Ramirez, D. E. Hasti, J. P. Corley, R. D. Genuario, H. N. Nishimoto, J. J. Fockler, I. D. Smith, P. D. A. Champney, K. E. Nielsen, L. G. Schlitt, and P. W. Spence, in Proceedings of the 5th IEEE Pulsed Power Conference, 10–12 June, 1985, edited by M. F. Rose and P. J. Turchi (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 1985), IEEE Catalog No. 85C2121-2, p. 143.
6.
J. J. Ramirez, K. R. Prestwich, E. L. Burgess, J. P. Furaus, R. A. Hamil, D. L. Johnson, T. W. L. Sanford, L. O. Seamons, L. X. Schneider, and G. A. Zawadzkas, in Proceedings of the 6th IEEE Pulsed Power Conference, 29 June–1 July, 1987, edited by P. J. Turchi and B. H. Bernstein (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 1987), IEEE Catalog No. 87CH2522-1, p. 294
7.
D. V. Rose, D. R. Welch, B. V. Oliver, R. E. Clark, J. E. Maenchen, C. L. Olson, P. R. Menge, D. C. Rovang, R. J. Commisso, G. Cooperstein, J. W. Schumer, and S. B. Swanekamp, in Conference Records—Abstracts, 2000 IEEE International Conference on Plasma Science, New Orleans, Louisiana, 4–7 June, 2000 (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 2000), IEEE Catalog No. 00CH37087, p. 232.
8.
D. V.
Rose
,
D. R.
Welch
,
B. V.
Oliver
,
R. E.
Clark
,
D. L.
Johnson
,
J. E.
Maenchen
,
P. R.
Menge
,
C. L.
Olson
, and
D. C.
Rovang
,
J. Appl. Phys.
91
,
3328
(
2002
).
9.
W. A. Stygar, R. B. Spielman, H. C. Ives, W. B. S. Moore, J. F. Seamen, A. W. Sharpe, T. C. Wagoner, T. L. Gilliland, R. S. Broyles, J. A. Mills, T. A. Dinwoodie, J. S. Slopek, K. W. Struve, and P. G. Reynolds, in Proceedings of the 11th IEEE International Pulsed Power Conference, Baltimore, Maryland, 29 June–2 July, 1997, edited by G. Cooperstein and I. Vitkovitsky (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 1997), IEEE Catalog No. 97CH36127, p. 1258.
10.
J. C. Dainty and R. Shaw, Image Science (Academic, New York, 1974), Chap. 6.
11.
J. M.
Creedon
,
J. Appl. Phys.
48
,
1070
(
1977
).
12.
M. E. Cuneo, J. W. Poukey, C. W. Mendel, S. E. Rosenthal, D. L. Hanson, J. R. Smith, J. E. Maenchen, D. F. Wenger, and M. A. Bernard, in Proceedings of the 9th IEEE International Pulsed Power Conference, Albuquerque, NM, 21–23 June, 1993, edited by K. Prestwich and W. Baker (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 1993), IEEE Catalog No. 93CH3350-6, p. 423.
13.
B. V. Oliver, T. C. Genoni, D. V. Rose, and D. R. Welch, in Proceedings of the 13th IEEE International Pulsed Power Conference, Las Vegas, NV, 17–22 June, 2001, edited by R. E. Reinovsky and M. A. Newton (Institute of Electrical and Electronic Engineers, Piscataway, NJ, 2001), IEEE Catalog No. 01CH37251, p. 458.
14.
I.
Langmuir
and
K.
Blodgett
,
Phys. Rev.
22
,
347
(
1923
).
15.
M. E.
Cuneo
,
IEEE Trans. Dielectr. Electr. Insul.
6
,
469
(
1999
).
16.
P. R.
Menge
and
M. E.
Cuneo
,
IEEE Trans. Plasma Sci.
25
,
252
(
1997
).
17.
D. R.
Welch
,
M. E.
Cuneo
,
C. L.
Olson
, and
T. A.
Mehlhorn
,
Phys. Plasmas
3
,
2113
(
1996
).
This content is only available via PDF.
You do not currently have access to this content.