Carbon ribbon gauge for electron beam diagnostics
Abstract
Large carbon and graphite monofilaments have been investigated for applications as an in-line diagnostic for pulsed electron beam irradiations of materials. The energy absorbed by the carbon ribbon causes a change in resistance which is measured a few microseconds after energy deposition. The measurement is therefore completed before there are any thermal losses or before the ribbon is broken by debris (from either specimen or anode materials). Both laboratory resistance and pulsed electron beam heating tests were made on carbon and graphitized carbon ribbon, and on Poco graphite rods. The first two materials survived doses up to 2000 cal/g; their resistance decreased with energy and they are suitable as a beam diagnostic up to 800 cal/g specific energy, above which their resistance change was insensitive to energy deposition. The Poco graphite resistance decreases by about 40% at doses of 200-400 cal/g, then increases at about 2-3% per 100 cal/g. This material would be a suitable beam monitor for doses from 400 cal/g to 1200 cal/g, and probably to 1700 cal/g and above. Additional work is required relating resistance change for these materials to absorbed ribbon dose, and determination of the maximum dose for which the Poco graphite can be used.
- Publication:
-
Carbon ribbon gauge for electron beam diagnostics AFWL
- Pub Date:
- May 1976
- Bibcode:
- 1976crge.rept.....K
- Keywords:
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- Carbon Fibers;
- Electron Beams;
- Measuring Instruments;
- Pulsed Radiation;
- Diagnosis;
- Radiation Counters;
- Radiation Tolerance;
- Thermodynamics;
- Nuclear and High-Energy Physics