CERN Accelerating science

Article
Title	Dark Current and Multipacting in the Photocathode RF Guns at PITZ
Author(s)	Hui-Han, Jang ; Bähr, J W ; Flöttmann, Klaus ; Grabosch, H J ; Hartrott, Michael ; Krasilnikov, Mikhail ; Michelato, Paolo ; Miltchev, Velizar ; Monaco, Laura ; Oppelt, Anne ; Petrosyan, Bagrat ; Riemann, S ; Roensch, Juliane ; Schreiber, Siegfried ; Sertore, Daniele ; Staykov, Lazar ; Stephan, Frank
Affiliation	(BESSY GmbH, Berlin) ; (DESY Zeuthen, Zeuthen) ; (DESY, Hamburg) ; (INFN/LASA, Segrate (MI) ; (Uni HH, Hamburg)
Publication	2005
In:	21st IEEE Particle Accelerator Conference, Knoxville, TN, USA, 16 - 20 May 2005, pp.895
Subject category	Accelerators and Storage Rings
Abstract	For photocathode rf guns, the amount of dark current depends on the cavity surface and the photocathodes. Smooth conditioning reduces the amount of dark current. Mechanical damages of the cathodes induce high dark current and chemical pollution changes emission properties of the cathode. Multipacting in the gun cavity changes the surface status of the cathodes and sometimes makes the gun operation impossible due to vacuum interlocks. In this paper, dark current and multipacting features of the rf gun are presented including experimental and simulation studies.