Performance of a DC GaAs photocathode gun for the Jefferson lab FEL

Conference · Sat Dec 01 00:00:00 EST 2001

OSTI ID:954829

Grippo, Albert; Yunn, Byung; Sinclair, Charles; Bohn, Courtlandt; Douglas, David; Bullard, Donald; Krafft, Geoffrey; Gubeli, Joseph; Siggins, Timothy

The performance of the 320kV DC photocathode gun has met the design specifications for the 1kW IR Demo FEL at Jefferson Lab. This gun has shown theability to deliver high average current beam with outstanding lifetimes. The GaAs photocathode has delivered 135pC per bunch, at a bunch repetition rate of37.425MHz, corresponding to 5mA average CW current. In a recent cathode lifetime measurement, 20h of CW beam was delivered with an average currentof 3.1mA and 211C of total charge from a 0.283cm2 illuminated spot. The cathode showed a 1/e lifetime of 58h and a1/e extracted charge lifetime of 618C.We have achieved quantum efficiencies of 5% from a GaAs wafer that has been in service for 13 months delivering in excess 2400C with only three activationcycles.

• Research Organization: Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
• Sponsoring Organization: USDOE
• DOE Contract Number: AC05-84ER40150
• OSTI ID: 954829
• Report Number(s): JLAB-ACC-01-46; TRN: US1004617
• Resource Relation: Conference: Talk compiled for 22nd International Free Electron Laser Conference And 7th FEL Users Workshop, 13-18 Aug 2000, Durham, North Carolina
• Country of Publication: United States
• Language: English

Related Subjects

43 PARTICLE ACCELERATORS
CATHODES
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