Phys. Rev. Lett. 100, 064801 (2008) [4 pages]Laser-Photofield Emission from Needle Cathodes for Low-Emittance Electron BeamsReceived 24 August 2007; published 13 February 2008 Illumination of a ZrC needle with short laser pulses (16 ps, 266 nm) while high voltage pulses (-60 kV, 2 ns, 30 Hz) are applied, produces photo-field emitted electron bunches. The electric field is high and varies rapidly over the needle surface so that quantum efficiency (QE) near the apex can be much higher than for a flat photocathode due to the Schottky effect. Up to 150 pC (2.9 A peak current) have been extracted by photo-field emission from a ZrC needle. The effective emitting area has an estimated radius below 50 μm leading to a theoretical intrinsic emittance below 0.05 mm mrad. © 2008 The American Physical Society URL:
http://link.aps.org/doi/10.1103/PhysRevLett.100.064801
DOI:
10.1103/PhysRevLett.100.064801
PACS:
29.25.Bx, 41.60.Cr, 79.70.+q, 85.45.Db
|
|
About | Terms and Conditions | Subscriptions | Search | Help
Use of the American Physical Society websites and journals implies that the user has read and agrees to our Terms and Conditions and any applicable Subscription Agreement. Physical Review®, Physical Review Letters®, Reviews of Modern Physics®, and Physical Review Special Topics® are trademarks of the American Physical Society.