1. Photoemission characterization of N-polar III-nitride photocathodes as candidate bright electron beam sources for accelerator applications.
- Author
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Cultrera, L., Rocco, E., Shahedipour-Sandvik, F., Bell, L. D., Bae, J. K., Bazarov, I. V., Saha, P., Karkare, S., and Arjunan, A.
- Subjects
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ELECTRON sources , *ELECTRON beams , *ELECTRON affinity , *PHOTOEMISSION , *PHOTOCATHODES , *QUANTUM efficiency - Abstract
We report on the growth and characterization of a new class of photocathode structures for use as electron sources to produce high brightness electron beams for accelerator applications. The sources are realized using III-nitride materials and are designed to leverage the strong polarization field, which is characteristic of this class of materials when grown in their wurtzite crystal structure, to produce a negative electron affinity condition without the use of Cs, possibly allowing these materials to be operated in radio frequency guns. A Quantum Efficiency (QE) of about 1 × 10 − 3 and an emitted electrons' Mean Transverse Energy (MTE) of about 100 meV are measured at a wavelength of 265 nm. In a vacuum level of 3 × 10 − 10 Torr, the QE does not decrease after more than 24 h of continuous operation. The lowest MTE of about 50 meV is measured at 300 nm along with a QE of 1.5 × 10 − 5 . Surface characterizations reveal a possible contribution to the MTE from surface morphology, calling for more detailed studies. [ABSTRACT FROM AUTHOR]
- Published
- 2022
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