K-Te photocathodes deposited on a Mo substrate have been successfully used as an electron source in the free electron laser of University of Twente. Long lifetimes have been measured: after more than 20 h of operation in the accelerator a K-Te cathode with 4.75% initial quantum efficiency still displays a 1.1% quantum efficiency at 259 mm. Moreover, the quantum efficiency of this cathode versus operation time can be fitted by an exponential decay curve, which saturates asymptotically to a 1.03% value, suggesting that a quantum efficiency close to 1% could be sustained for very long operation times. Films degraded by use can be recovered to a quantum efficiency which is close To the initial value, by heating the substrate al temperatures between 100 and 330 degrees C. A new procedure to obtain K-Te cathodes with high (up to 11%) quantum efficiencies is described. (C) 1997 American Institute of Physics.

K-Te photocathodes: A new electron source for photoinjectors

BISERO, Diego;
1997

Abstract

K-Te photocathodes deposited on a Mo substrate have been successfully used as an electron source in the free electron laser of University of Twente. Long lifetimes have been measured: after more than 20 h of operation in the accelerator a K-Te cathode with 4.75% initial quantum efficiency still displays a 1.1% quantum efficiency at 259 mm. Moreover, the quantum efficiency of this cathode versus operation time can be fitted by an exponential decay curve, which saturates asymptotically to a 1.03% value, suggesting that a quantum efficiency close to 1% could be sustained for very long operation times. Films degraded by use can be recovered to a quantum efficiency which is close To the initial value, by heating the substrate al temperatures between 100 and 330 degrees C. A new procedure to obtain K-Te cathodes with high (up to 11%) quantum efficiencies is described. (C) 1997 American Institute of Physics.
Bisero, Diego; B. M., Vanoerle; G. J., Ernst; J. W. J., Verschuur; W. J., Witteman
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11392/1677325
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