Linear Accelerator Conference LINAC2010 - List of Authors (Pasky, S.J.)

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Pasky, S.J.

Paper	Title	Page
THP107	Experimental Investigation of Pulsed Laser Heating of Thermionic Cathodes of RF Guns	983
	N. Sereno, M. Borland, K.C. Harkay, Y.L. Li, R.R. Lindberg, S.J. Pasky ANL, Argonne
	One proposed injector for the X-ray Free Electron Laser Oscillator* uses a 100 MHz thermionic rf gun to deliver very small emittances at a 1 MHz rate. Since the required beam rate is only 1 MHz, 99\% of the beam must be dumped. In addition, back-bombardment of the cathode is a significant concern. To address these issues, we propose* using a laser to quickly heat the surface of a cathode in order to achieve gated thermionic emission in an rf gun. We have investigated this concept experimentally using an existing S-band rf gun with a thermionic cathode. Our experiments confirm that thermal gating is possible and that it shows some agreement with predictions. Operational issues and possible cathode damage are discussed. K. J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008) P. N. Ostroumov et al., Proc. Linac08, 676-678. **M. Borland et al., these proceedings.

Paper

Title

Page

THP107

Experimental Investigation of Pulsed Laser Heating of Thermionic Cathodes of RF Guns

983

N. Sereno, M. Borland, K.C. Harkay, Y.L. Li, R.R. Lindberg, S.J. Pasky
ANL, Argonne

One proposed injector for the X-ray Free Electron Laser Oscillator* uses a 100 MHz thermionic rf gun to deliver very small emittances at a 1 MHz rate**. Since the required beam rate is only 1 MHz, 99\% of the beam must be dumped. In addition, back-bombardment of the cathode is a significant concern. To address these issues, we propose*** using a laser to quickly heat the surface of a cathode in order to achieve gated thermionic emission in an rf gun. We have investigated this concept experimentally using an existing S-band rf gun with a thermionic cathode. Our experiments confirm that thermal gating is possible and that it shows some agreement with predictions. Operational issues and possible cathode damage are discussed.

*K. J. Kim et al., Phys. Rev. Lett. 100, 244802 (2008)
**P. N. Ostroumov et al., Proc. Linac08, 676-678.
***M. Borland et al., these proceedings.