Project: Photo-Catch, SPIN

Description:

Gallium arsenide (GaAs) photocathode-based electron sources can be used to generate high intensity spin-polarized electron beams for a variety of applications. In this process, the GaAs surface is covered by a thin layer, typically consisting of cesium and an oxidant, to achieve negative electron affinity (NEA). This results in a higher quantum yield. This highly reactive layer will degrade even in good vacuum conditions due to storage and beam operation. For the most effective and smooth operation of such an electron source at a particle accelerator, the longest possible layer lifetime is essential. Both the quantum yield and the layer lifetime depend on the fabrication procedure of the NEA layer.

In this work, such an activation procedure will be optimized on the Photo-CATCH test stand with respect to quantum yield and lifetime. In addition, activations with lithium insertion will be investigated within the scope of this work. Thus, a reproducible optimal procedure for the formation of the NEA layer shall be determined.

Techniques: LabVIEW, Datenauswertung, Vakuumtechnik, Lasersysteme

Contact: Maximilian Herbert, Yuliya Fritzsche

Resources

• LabVIEW