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Title: Charge Lifetime Study of K2CsSb Photocathode Inside a JLAB DC High Voltage Gun

Abstract

Two photocathodes are frequently considered for generating high average current electron beams and/or beams with high brightness for current and future accelerator applications: GaAs:Cs and K2CsSb. Each photocathode has advantages and disadvantages, and need to demonstrate performance at 'production' accelerator facilities. To this end a K2CsSb photocathode was manufactured at Brookhaven National Lab and delivered to Jefferson Lab within a compact vacuum apparatus at pressure {approx} 5 x 10{sup -11} Torr. This photocathode was installed inside a dc high voltage photogun biased at voltages up to 200 kV, and illuminated with laser light at 440 or 532 nm, to generate beams up to 20 mA. Photocathode charge lifetime measurements indicate that under some conditions this cathode has exceptionally high charge lifetime, without measurable QE decay, even from the center of the photocathode where operation using GaAs photocathodes is precluded due to ion bombardment. These studies also suggest a complex QE decay mechanism likely related to chemistry and localized heating via the laser beam.

Authors:
; ; ; ; ;
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE SC OFFICE OF SCIENCE (SC)
OSTI Identifier:
1041511
Report Number(s):
BNL-96532-2011-JA
KA-04; TRN: US1202664
DOE Contract Number:  
DE-AC02-98CH10886
Resource Type:
Journal Article
Journal Name:
Proceedings of IPAC2011
Additional Journal Information:
Conference: IPAC2011; San Sebastian, Spain; 20110904 through 20110909
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; 46 INSTRUMENTATION RELATED TO NUCLEAR SCIENCE AND TECHNOLOGY; ACCELERATOR FACILITIES; ACCELERATORS; BRIGHTNESS; CATHODES; CHEMISTRY; DECAY; ELECTRON BEAMS; HEATING; LASERS; LIFETIME; PERFORMANCE; PHOTOCATHODES; PRODUCTION

Citation Formats

Mammei, R, Rao, T, Suleiman, R, Poelker, M, Smedley, J, and McCarter, J L. Charge Lifetime Study of K2CsSb Photocathode Inside a JLAB DC High Voltage Gun. United States: N. p., 2011. Web.
Mammei, R, Rao, T, Suleiman, R, Poelker, M, Smedley, J, & McCarter, J L. Charge Lifetime Study of K2CsSb Photocathode Inside a JLAB DC High Voltage Gun. United States.
Mammei, R, Rao, T, Suleiman, R, Poelker, M, Smedley, J, and McCarter, J L. Sat . "Charge Lifetime Study of K2CsSb Photocathode Inside a JLAB DC High Voltage Gun". United States.
@article{osti_1041511,
title = {Charge Lifetime Study of K2CsSb Photocathode Inside a JLAB DC High Voltage Gun},
author = {Mammei, R and Rao, T and Suleiman, R and Poelker, M and Smedley, J and McCarter, J L},
abstractNote = {Two photocathodes are frequently considered for generating high average current electron beams and/or beams with high brightness for current and future accelerator applications: GaAs:Cs and K2CsSb. Each photocathode has advantages and disadvantages, and need to demonstrate performance at 'production' accelerator facilities. To this end a K2CsSb photocathode was manufactured at Brookhaven National Lab and delivered to Jefferson Lab within a compact vacuum apparatus at pressure {approx} 5 x 10{sup -11} Torr. This photocathode was installed inside a dc high voltage photogun biased at voltages up to 200 kV, and illuminated with laser light at 440 or 532 nm, to generate beams up to 20 mA. Photocathode charge lifetime measurements indicate that under some conditions this cathode has exceptionally high charge lifetime, without measurable QE decay, even from the center of the photocathode where operation using GaAs photocathodes is precluded due to ion bombardment. These studies also suggest a complex QE decay mechanism likely related to chemistry and localized heating via the laser beam.},
doi = {},
url = {https://www.osti.gov/biblio/1041511}, journal = {Proceedings of IPAC2011},
number = ,
volume = ,
place = {United States},
year = {2011},
month = {10}
}