NASA/TM-209762, Nunes, Jr., A.C. and Russell, C.K. and Zimmerman, F.R. and Fragomeni*, J.M., Low-Pressure Gas Effects on the Potency of an Electron Beam Against Ceramic Cloth, Materials and Processes Laboratory, Science and Engineering Directorate, NASA Marshall Space Flight Center, AL 35812, *Ohio University, Athens, Ohio, November 1999, pp. 28, Format(s): PDF 310k |
An 8-kv electron beam with a current in the neighborhood of 100 mA from the Ukrainian spacewelding "Universal Hand Tool" (UHT) burned holes in Nextel AF-62 ceramic cloth designed to withstand temperatures up to 1,427 C degrees. The burnthrough time was on the order of 8 sec at standoff distances between UHT and cloth ranging from 6-24 in. At both closer (2 in.) and farther (48 in.)standoff distances the potency of the beam against the cloth declined and the burnthrough time went up significantly. Prior to the test it had been expected that the beam would lay down a static charge on the cloth and be deflected without damaging the cloth. The burnthrough is thought to be an effect of partial transmission of beam power by a stream of positive ions generated by the high-voltage electron beam from contaminant gas in the "vacuum" chamber. A rough quantitative theoretical computation appears to substantiate this possibility
| Keywords: | electron beam, welding, damage |
|---|---|
| Subjects: | Engineering: Engineering (General) |
| ID Code: | 499 |
| Deposited On: | 24 July 2002 |