Green light for photocathodes – BMBF funds joint German-Russian collaboration on the physics of photocathodes for high brightness electron beams (PCHB)

The photocathode electron injector is a significant enabling concept for light sources based on the Energy Recovery Linac (ERL) and Free Electron Lasers. Successful operation of such sources require photocathodes with reliable, uniform and long lifetime high quantum efficiency, low thermal emittance and low dark current. The BMBF funded project will investigate options for cathodes which fulfill the requirements asked for and uncover correlations between cathode preparation and electron beam parameters.

 
The unique close interaction of specialists in the fields of semiconductor theory, experimental physicist in the fields of accelerator physics and surface science and the possibility to test the new materials in established and novel electron injectors opens an exceptional platform for cathode research and development. Being wide-ranged the project is offering the possibility to perform exceptional, interdisciplinary and international research and therefore take on a role in the education of students and young scientist.


The five partners of the three-year project are from the German side as lead laboratory Helmholtz-Zentrum Berlin (HZB, project leader: Dr. Thorsten Kamps), Johannes-Gutenberg University Mainz (JGU, Dr. Kurt Aulenbacher) and Helmholtz-Zentrum Dresden Rossendorf (HZDR, Dr. Jochen Teichert), from the Russian site Saint-Petersburg State Polytechnic University (SPSPU, Prof. Dr. Yuri Mamev) and Skobeltsyn Institute of Nuclear Physics Lomonosow Moscow State University (MSU, Dr. Vasily Shvedunov) are participating.


Heinrich Hertz observed in 1887 that electrodes illuminated with ultraviolet light create electric sparks more easily. The mathematical description of how the photoelectric effect was caused by photons (quanta of light) won Albert Einstein the Nobel Prize in Physics in 1921. We know that electrons are dislodged from the atomic hosts, but there is still much to learn on the details on how they are liberated. The understanding of this will be the base for a theoretical model which allows us to predict beam properties for the next generation of photocathodes.

Thorsten Kamps