National Technical Reports Library

The National Technical Information Service acquires, indexes, abstracts, and archives the largest collection of U.S. government-sponsored technical reports in existence. The NTRL offers online, free and open access to these authenticated government technical reports. Technical reports and documents in its repository may be available online for free either from the issuing federal agency, the U.S. Government Publishing Office’s Federal Digital System website, or through search engines.

Details

DE2007917249

Publication Date	2007
Personal Author	Grames, J.; Poelker, M.; Adderley, P.; Brittian, J.; Clark, J.
Page Count	8
Abstract	This work extends past research at Jefferson Lab aimed at better appreciating the mechanisms that limit photocathode operational lifetime at high current (> 1 mA). Specifically, the performance of an improved 100 kV DC high voltage load locked photogun will be described. Although difficult to measure directly, we believe the new gun has better vacuum conditions compared to the original gun, as indicated by enhanced photocathode lifetimes exceeding 2000 C using a 1.55 mm diameter drive laser spot at the photocathode. In addition, the dependence of the lifetime on the laser spot size at the photocathode was measured and a charge density lifetime exceeding 10(caret)6 C/cm(caret)2 was measured with a 0.32 mm laser spot diameter.
Keywords	Photocathodes Beam currents Lifetime Vaccum systems Measurement High voltages Performance Gallium arsenides Photogun Drive lasers
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Thomas Jefferson National Accelerator Facility, Newport News, VA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200806

Measurements of Photocathode Operational Lifetime at Beam Currents up to 10 mA using an Improved DC High Voltage GaAs Photogun.

Measurements of Photocathode Operational Lifetime at Beam Currents up to 10 mA using an Improved DC High Voltage GaAs Photogun.
DE2007917249

Publication Date	2007
Personal Author	Grames, J.; Poelker, M.; Adderley, P.; Brittian, J.; Clark, J.
Page Count	8
Abstract	This work extends past research at Jefferson Lab aimed at better appreciating the mechanisms that limit photocathode operational lifetime at high current (> 1 mA). Specifically, the performance of an improved 100 kV DC high voltage load locked photogun will be described. Although difficult to measure directly, we believe the new gun has better vacuum conditions compared to the original gun, as indicated by enhanced photocathode lifetimes exceeding 2000 C using a 1.55 mm diameter drive laser spot at the photocathode. In addition, the dependence of the lifetime on the laser spot size at the photocathode was measured and a charge density lifetime exceeding 10(caret)6 C/cm(caret)2 was measured with a 0.32 mm laser spot diameter.
Keywords	Photocathodes Beam currents Lifetime Vaccum systems Measurement High voltages Performance Gallium arsenides Photogun Drive lasers
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Thomas Jefferson National Accelerator Facility, Newport News, VA.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200806