DIAMOND AMPLIFIED PHOTOCATHODES.
High-average-current linear electron accelerators require photoinjectors capable of delivering tens to hundreds of mA average current, with peak currents of hundreds of amps. Standard photocathodes face significant challenges in meeting these requirements, and often have short operational lifetimes in an accelerator environment. We report on recent progress toward development of secondary emission amplifiers for photocathodes, which are intended to increase the achievable average current while protecting the cathode from the accelerator. The amplifier is a thin diamond wafer which converts energetic (few keV) primary electrons into hundreds of electron-hole pairs via secondary electron emission. The electrons drift through the diamond under an external bias and are emitted into vacuum via a hydrogen-terminated surface with negative electron affinity (NEA). Secondary emission gain of over 200 has been achieved. Two methods of patterning diamond, laser ablation and reactive-ion etching (RIE), are being developed to produce the required geometry. A variety of diagnostic techniques, including FTIR, SEM and AFM, have been used to characterize the diamonds.
- Research Organization:
- Brookhaven National Lab. (BNL), Upton, NY (United States)
- Sponsoring Organization:
- Doe - Office Of Science
- DOE Contract Number:
- DE-AC02-98CH10886
- OSTI ID:
- 922243
- Report Number(s):
- BNL-79737-2008-CP; R&D Project: 07032; KA-04; TRN: US0801028
- Resource Relation:
- Conference: MATERIALS RESEARCH SOCIETY FALL MEETING; BOSTON, MASSACHUSETTS; 20071126 through 20071130
- Country of Publication:
- United States
- Language:
- English
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Diamond Amplifier For Photocathodes
DIAMOND AMPLIFIER FOR PHOTOCATHODES.