Electron beam in the gun!

On Thursday 19 January a technological breakthrough was made at the MAX IV project. For the first time an electron beam found its way from the new photo cathode radio frequency gun (photo cathode RF gun for short) to the first Yttrium Aluminium Garnet screen (YAG) in the radio frequency test bed (se picture below). The photo cathode RF gun shall be used in the MAX IV 3 GeV ring's injector, and it will give an electron beam for the short pulse facility and free electron laser applications.

A lot of heat can be produced by long radio frequency pulses in time and high pulse repetition frequency (100 Hz, PRF), and we want to avoid that. For the first time, a SLED-system is used to compress the radio frequency pulse before it feeds the gun with radio frequency pulse. That implies that we will get the correct electric field in the gun in less of one third of the time that is needed without compression.

The gun that is tested will eventually be moved to MAX IV, and it is completely developed and produced by us here at the MAX IV Laboratory. Dionis Kumbaro is the project manager of this project, and he has together with several coworkers at the MAX IV Laboratory developed and constructed the radio frequency gun test bed to be able to test the new technology. Since the gun is tested and adjusted now, we will save time when it will be installed at MAX IV.

The photo cathode RF gun that will be used for short pulse and free electron laser experiments is one of two RF guns that will be used at MAX IV. The other gun is a so called thermionic RF gun, and it will be used for the storage rings. The thermionic RF gun at MAX IV will be developed by us at the MAX IV Laboratory as well, and it will be constructed in June this year. But before that more testing of the photo cathode RF gun remains to achieve the right electron charge, electron energy, and the demanded emittance.