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Title: Surface ionization microscope

Abstract

A surface ionization microscope was developed for the study of cesium ionization on porous refractory metal structures. The microscope consists of an ionizer-cesium reservoir unit, electrostatic immersion lens, an ionelectron image converter, and a phosphor screen. The ionizer can be heated to 1400 deg C. The cesium reservoir has a separate heater and thermocouple probe. The ionizer surface forms the first element of a three element electrostatic immersion lens. The second and third elements are part of a fixture which can be moved along the optical axis of the system. By adjusting the position and the voltage ratios of the elements magnifications of the ionizer from 25 to 200x are obtained. A traversing mechanism is employed to move the ionizer and permit scanning over the ionizer surface. All these adjustments can be made during operation of the microscope. The ion-electron converter is an electro-formed nickel screen, held at ground potential. It is placed in front of an aluminized phosphor which is maintained at +10 kv. lons incident on the nickel screen produce secondary electrons which are pulled through the open areas and accelerated into the phosphor by the electrostatic field. The microscope was used to observe both ion emission andmore » electron emission from various ionizers. Results from tungsten wire bundles and commercial sintered tungsten powder are presented. Both show wide variations in surface ion emission. The wire bundle is seen to operate under three conditions simultaneously. An analytical solution which explains this phenomenon is pointed out. The ion microscope gives a picture which immediately shows the distribution and uniformity of ion emission from a surface ionizer and allows one to observe the effects of pore size, crystal orientation, gas adsorption, braze penetration, and other pertinent characteristics. (auth) H03 H0236135 An electric discharge tube, which is provided with an H replenisher, and a method of manufacturing it are patented. The tube and electrodes are degassed, and the H-replenisher component is then coated with a finely divided metal by atomization in a rare-gas glow discharge or by vaporization in a rare-gas atmosphere. The finely divided metal may be Zr or Ti and is capable of reversibly absorbing H. After being coated on the H replenisher, which is a thinwalled metal sheath surrounding a heater, it is saturated with H, and any excess gas is removed from the discharge tube. The H replenisher is particularly useful in a neutron generator, which is divided into 2 parts by an apertured partition, each part being provided with a replenisher. (M.P.G.)« less

Authors:
; ;
Publication Date:
Sponsoring Org.:
Sponsor not identified
OSTI Identifier:
4876235
Report Number(s):
CONF-10-30; Preprint-63018
NSA Number:
NSA-17-036134
Resource Type:
Conference
Resource Relation:
Conference: AIAA Electric Propulsion Conference, Colorado Springs, CO (United States), 11-13 Mar 1963
Country of Publication:
United States
Language:
English
Subject:
INSTRUMENTS AND INSTRUMENTATION; ADSORPTION; ALUMINUM; BRAZING; CESIUM; CRYSTALS; DISTRIBUTION; EFFICIENCY; ELECTRIC POTENTIAL; ELECTRONS; ELECTROSTATICS; EMISSION; GASES; HEATING; IMAGES; IONIZATION; IONS; LENSES; LUMINESCENCE; MECHANICAL STRUCTURES; MICROSCOPY; MOTION; NICKEL; OPERATION; PHOSPHORS; PLATES; POROSITY; REFRACTORIES; SINTERED MATERIALS; SURFACES; THERMOCOUPLES; TUNGSTEN; WIRES

Citation Formats

Marchant, A. B., Kuskevics, G., and Forrester, A. T. Surface ionization microscope. United States: N. p., 1963. Web.
Marchant, A. B., Kuskevics, G., & Forrester, A. T. Surface ionization microscope. United States.
Marchant, A. B., Kuskevics, G., and Forrester, A. T. 1963. "Surface ionization microscope". United States. https://www.osti.gov/servlets/purl/4876235.
@article{osti_4876235,
title = {Surface ionization microscope},
author = {Marchant, A. B. and Kuskevics, G. and Forrester, A. T.},
abstractNote = {A surface ionization microscope was developed for the study of cesium ionization on porous refractory metal structures. The microscope consists of an ionizer-cesium reservoir unit, electrostatic immersion lens, an ionelectron image converter, and a phosphor screen. The ionizer can be heated to 1400 deg C. The cesium reservoir has a separate heater and thermocouple probe. The ionizer surface forms the first element of a three element electrostatic immersion lens. The second and third elements are part of a fixture which can be moved along the optical axis of the system. By adjusting the position and the voltage ratios of the elements magnifications of the ionizer from 25 to 200x are obtained. A traversing mechanism is employed to move the ionizer and permit scanning over the ionizer surface. All these adjustments can be made during operation of the microscope. The ion-electron converter is an electro-formed nickel screen, held at ground potential. It is placed in front of an aluminized phosphor which is maintained at +10 kv. lons incident on the nickel screen produce secondary electrons which are pulled through the open areas and accelerated into the phosphor by the electrostatic field. The microscope was used to observe both ion emission and electron emission from various ionizers. Results from tungsten wire bundles and commercial sintered tungsten powder are presented. Both show wide variations in surface ion emission. The wire bundle is seen to operate under three conditions simultaneously. An analytical solution which explains this phenomenon is pointed out. The ion microscope gives a picture which immediately shows the distribution and uniformity of ion emission from a surface ionizer and allows one to observe the effects of pore size, crystal orientation, gas adsorption, braze penetration, and other pertinent characteristics. (auth) H03 H0236135 An electric discharge tube, which is provided with an H replenisher, and a method of manufacturing it are patented. The tube and electrodes are degassed, and the H-replenisher component is then coated with a finely divided metal by atomization in a rare-gas glow discharge or by vaporization in a rare-gas atmosphere. The finely divided metal may be Zr or Ti and is capable of reversibly absorbing H. After being coated on the H replenisher, which is a thinwalled metal sheath surrounding a heater, it is saturated with H, and any excess gas is removed from the discharge tube. The H replenisher is particularly useful in a neutron generator, which is divided into 2 parts by an apertured partition, each part being provided with a replenisher. (M.P.G.)},
doi = {},
url = {https://www.osti.gov/biblio/4876235}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1963},
month = {3}
}

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