Impedance collapse and beam generation in a high power planar diode

Journal Article · Tue Jul 01 04:00:00 EDT 2008 · Journal of Applied Physics

DOI:https://doi.org/10.1063/1.2951743· OSTI ID:21137391

Roy, Amitava; Menon, R; Mitra, S; Kumar, D D. P.; Kumar, Senthil; Sharma, Archana; Mittal, K C; Nagesh, K V; Chakravarthy, D P ^[1]

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1. Accelerator and Pulse Power Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400 085 (India)

Intense relativistic electron beam generation studies were carried out in a planar diode configuration to investigate the effect of the plasma expansion on the impedance characteristics of the diode. The typical electron beam parameter was 280 kV, 18 kA, 100 ns, with a few hundreds of A/cm{sup 2} current density. The diode voltage and current waveforms were analyzed with the bipolar space-charge limited flow model. The anode and cathode plasma expansion velocities were calculated using the perveance data. The plasma expands at 9.5 cm/{mu}s for 31 mm anode-cathode gap and the plasma velocity decreases for smaller gap. It was found that the electron emission is more uniform for 25 mm anode-cathode gap as compared to 31 mm gap. Effect of a nylon sheet on the anode plate has been studied with respect to the impedance characteristic of the diode. It was found that the diode closes at a faster rate in the presence of nylon sheet on anode. Nylon materials are released into the diode region due to the electron beam bombardment and get deposited on the cathode. This deposition affects the subsequent electron beam generation.

• OSTI ID: 21137391
• Journal Information: Journal of Applied Physics, Journal Name: Journal of Applied Physics Journal Issue: 1 Vol. 104; ISSN JAPIAU; ISSN 0021-8979
• Country of Publication: United States
• Language: English

Related Subjects

71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ANODES
CATHODES
CURRENT DENSITY
ELECTRIC POTENTIAL
ELECTRON BEAMS
ELECTRON EMISSION
FLOW MODELS
IMPEDANCE
NYLON
PLASMA
PLASMA EXPANSION
RELATIVISTIC RANGE
SPACE CHARGE
THERMIONIC DIODES
WAVE FORMS