ELBE SRF Gun I – The World’s First SRF Gun Operating for a LINAC, 2007 – 2014

In 2004 the project for the ELBE SRF gun was launched. The goals of this project are to build a new electron source[1] with 1 mA average current in cw-operation and with low emittance for the ELBE superconducting linear accelerator, as well as to demonstrate the capability for the future applications in FEL light sources and energy recovery linacs. The injector together with the UV driver laser system and the diagnostic beam line were developed and constructed in collaboration with the German institutes DESY, HZB, MBI, and the project was one task in the Coordinated Accelerator Research in Europe (CARE) activity supported by the European Commission. Furthermore there has been a strong financial support by the German Federal Ministry of Education and Research. The SRF gun project at HZDR has two main goals: the installation of a high-brightness photo-injector for ELBE, and contributing to the SRF gun development as a promising future technology.

old gun whole

The ACC 300 cavity

The heart of this first SC photo injector for ELBE is a 3.5-cell niobium cavity[2]. The cavity named ACC300 was designed at HZDR and produced by the company ACCEL Instruments (now RI Research Instruments).


  • In summer 2007 the SRF gun was installed in the ELBE accelerator hall.
  • On November 12, 2007, the first accelerated electron beam was generated which was extracted from a Cu photo cathode. (first beam 12.11.2007)
  • In March 2008 the cathode transfer system was mounted and the first set of Cs2Te photo cathodes was produced. Since May 2008 the gun has been operated with these cathodes.[3]
  • In the winter shutdown 2009/10 the connection beam line was installed, which now allows to inject the electron beam into the ELBE accelerator.
  • In February 2010 the SRF gun beam was injected into ELBE for the first time.[4]
  • In September 2011production of x-ray by means of a Thomson backscattering experiment with DRACO laser beam and the electron beam injected by SRF gun in ELBE.
  • In April 2013 the first lasing with the SRF gun electron beam and the ELBE far-infrared free-electron laser.[5]


[1] A. Arnold, et al., Development of a superconducting radio frequency photo injector, Nucl. Instr.and Meth. A 577 (2007) 440-454

[2] J. Teichert, et al., A superconducting photo-injector with a 3 ½ cell cavity for the ELBE LINAC, Proceedings of EPAC 2004, Lucerne, Switzerland, p. 333-335

[3] J. Teichert, et al., Initial Commissioning Experience with the Superconducting RF Photoinjector atELBE, Proceedings of FEL´08, August 24 -29, 2008, Gyeongju, Korea

[4] R. Xiang, et al., The elbe accelerator facility starts operation with the superconducting rf gun, Proceedings of IPAC’10, Kyoto, Japan, 23-28.05.2010.

[5] J. Teichert, et al., Free-electron laser operation with a superconducting radio-frequency photoinjector at ELBE, Nuclear Instruments and Methods in Physics Research A 743 (2014) 114-120