Current densities and closure rates in diodes containing laser-driven, cesium-coated thermionic cathodes
Journal Article
·
· J. Appl. Phys.; (United States)
Cathodes emitting electron current pulses of 10/sup 2/--10/sup 3/ A/cm/sup 2/ for durations of longer than 1 ..mu..s, with very low emittance, are desirable for free electron laser and high-power microwave tube applications. Not all of these criteria can be satisfied by either dispenser thermionic cathodes or plasma forming field emitters. However, pulse-laser heated smooth cesiated refractory metal surfaces have the potential to achieve these conditions. In this paper, test results from low-voltage (2--20 kV) diodes containing cesiated tungsten cathodes are discussed. Space-charge-limited current densities of up to 30 A/cm/sup 2/ were obtained in fields with maximum strengths of 40 kV/cm. Plasma closure rates at these currents were measured to be 0.17--0.4 cm/..mu..s. Such slow velocity fronts are postualted to be due to the domination of the plasma by massive cesium ions generated from species desorbed from the cathode, rather than to light hydrogen ions (as in the case of field-emission-type cathodes).
- Research Organization:
- Thermo Electron Corporation, 85 First Avenue, Waltham, Massachusetts 02254
- OSTI ID:
- 5526495
- Journal Information:
- J. Appl. Phys.; (United States), Journal Name: J. Appl. Phys.; (United States) Vol. 58:5; ISSN JAPIA
- Country of Publication:
- United States
- Language:
- English
Similar Records
Program to research laser-driven thermionic electron sources for free-electron lasers. Final report
A high current H{sup {minus}} radio frequency volume ion source
BASIC RESEARCH IN THERMIONICS. PART I. CESIUM PERMEATION THROUGH TANTALUM. Summary Report No. 1, November 1, 1961 to October 31, 1962
Technical Report
·
Thu Dec 31 23:00:00 EST 1987
·
OSTI ID:7199850
A high current H{sup {minus}} radio frequency volume ion source
Journal Article
·
Thu Jun 01 00:00:00 EDT 1995
· Review of Scientific Instruments
·
OSTI ID:56012
BASIC RESEARCH IN THERMIONICS. PART I. CESIUM PERMEATION THROUGH TANTALUM. Summary Report No. 1, November 1, 1961 to October 31, 1962
Technical Report
·
Mon Dec 31 23:00:00 EST 1962
·
OSTI ID:4640491
Related Subjects
36 MATERIALS SCIENCE
360104* -- Metals & Alloys-- Physical Properties
42 ENGINEERING
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
ALKALI METALS
BEAMS
CATHODES
CESIUM
CURRENT DENSITY
DATA
DIODE TUBES
ELECTRODES
ELECTRON BEAMS
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EMISSION
ENERGY RANGE
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
FREE ELECTRON LASERS
INFORMATION
KEV RANGE
KEV RANGE 01-10
KEV RANGE 10-100
LASERS
LEPTON BEAMS
METALS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
NUMERICAL DATA
PARTICLE BEAMS
THERMIONIC DIODES
THERMIONIC EMISSION
THERMIONIC TUBES
TRANSITION ELEMENTS
TUNGSTEN
VELOCITY
360104* -- Metals & Alloys-- Physical Properties
42 ENGINEERING
420800 -- Engineering-- Electronic Circuits & Devices-- (-1989)
ALKALI METALS
BEAMS
CATHODES
CESIUM
CURRENT DENSITY
DATA
DIODE TUBES
ELECTRODES
ELECTRON BEAMS
ELECTRON TUBES
ELECTRONIC EQUIPMENT
ELEMENTS
EMISSION
ENERGY RANGE
EQUIPMENT
EXPERIMENTAL DATA
FABRICATION
FREE ELECTRON LASERS
INFORMATION
KEV RANGE
KEV RANGE 01-10
KEV RANGE 10-100
LASERS
LEPTON BEAMS
METALS
MICROWAVE EQUIPMENT
MICROWAVE TUBES
NUMERICAL DATA
PARTICLE BEAMS
THERMIONIC DIODES
THERMIONIC EMISSION
THERMIONIC TUBES
TRANSITION ELEMENTS
TUNGSTEN
VELOCITY