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Title: Post-Removal Examination of GTF Cathode #2

Abstract

This photo-cathode (PC), GTF Cathode No.2, was removed from the GTF in October, 2000. It was characterized in September, 1999 by G. Mulhollan and me (Report entitled ''A Brief Report on a Brief Examination of the Electropolished GTF Cathode'', LCLS-TN-99-10). The cathode conditions and results of that exam were: (1) The cathode was conventionally machined and cleaned in the SLAC Plating Shop. (2) The machining process left a central defect (400 microns diameter) which was not removed by electropolishing. (3) The electropolished surface was ''orange-peeled'', typical of excessive polishing. (4) Secondary electron microscopy (SEM) examination showed numerous 10 micron-diameter etch pits and a small number of copper surface particles. Operation of this cathode in the GTF exhibited ''hollow-beam'' behavior, suggesting that the central defect may have been responsible for non-normal emergence of the photo-emitted beam. No laser cleaning of the cathode was done, so all arc features are due to breakdowns. Post-removal analysis consisted of low-magnification digital camera pictures (taken with glancing-incidence tungsten white light illumination, to emphasize particles/pitting) and SEM. All images are available in digital (TIFF) form. Also available is a Power Point presentation of the results. Contact me for either. These image files are high-resolution and, thus,more » large in size. A 200K low-resolution contact sheet of a few images is attached to this report. Images are referred to by file name.« less

Authors:
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC), Menlo Park, CA
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
839648
Report Number(s):
SLAC-TN-05-005
TRN: US0503491
DOE Contract Number:  
AC02-76SF00515
Resource Type:
Technical Report
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; CAMERAS; CATHODES; CLEANING; COPPER; DEFECTS; ELECTRON MICROSCOPY; ELECTROPOLISHING; ILLUMINANCE; LASERS; MACHINING; PLATING; POLISHING; STANFORD LINEAR ACCELERATOR CENTER; TUNGSTEN

Citation Formats

Kirby, R. Post-Removal Examination of GTF Cathode #2. United States: N. p., 2005. Web. doi:10.2172/839648.
Kirby, R. Post-Removal Examination of GTF Cathode #2. United States. doi:10.2172/839648.
Kirby, R. Wed . "Post-Removal Examination of GTF Cathode #2". United States. doi:10.2172/839648. https://www.osti.gov/servlets/purl/839648.
@article{osti_839648,
title = {Post-Removal Examination of GTF Cathode #2},
author = {Kirby, R},
abstractNote = {This photo-cathode (PC), GTF Cathode No.2, was removed from the GTF in October, 2000. It was characterized in September, 1999 by G. Mulhollan and me (Report entitled ''A Brief Report on a Brief Examination of the Electropolished GTF Cathode'', LCLS-TN-99-10). The cathode conditions and results of that exam were: (1) The cathode was conventionally machined and cleaned in the SLAC Plating Shop. (2) The machining process left a central defect (400 microns diameter) which was not removed by electropolishing. (3) The electropolished surface was ''orange-peeled'', typical of excessive polishing. (4) Secondary electron microscopy (SEM) examination showed numerous 10 micron-diameter etch pits and a small number of copper surface particles. Operation of this cathode in the GTF exhibited ''hollow-beam'' behavior, suggesting that the central defect may have been responsible for non-normal emergence of the photo-emitted beam. No laser cleaning of the cathode was done, so all arc features are due to breakdowns. Post-removal analysis consisted of low-magnification digital camera pictures (taken with glancing-incidence tungsten white light illumination, to emphasize particles/pitting) and SEM. All images are available in digital (TIFF) form. Also available is a Power Point presentation of the results. Contact me for either. These image files are high-resolution and, thus, large in size. A 200K low-resolution contact sheet of a few images is attached to this report. Images are referred to by file name.},
doi = {10.2172/839648},
journal = {},
number = ,
volume = ,
place = {United States},
year = {2005},
month = {1}
}

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