Spectrally resolved quantum efficiency of Potassium-cesium-antimony



Spectrally resolved quantum efficiency is a fundamental means for characterizing multi alkali photocathodes ( such as K2CsSb ) which are used as electron sources in particle accelerators such as MESA (Mainz Energy-Recovering Superconducting Accelerator) and BerlinPRO.

The quantum efficiency displays the ratio between the generated photocurrent and the incident spectral flux over a wavelength bandwidth of 400-600nm. The gathered information is used to understand the internal transport mechanisms of these semiconductor materials.


A spectrometer with a lightsource and a monochromator is put into operation and existing or self-made photocathodes are measured.

Project scope :

- Construction of a test facility to measure the spectral quantum efficiency (Xe lamp / monochromator / channeltron)

- Integration into an existing setup for the production of photocathodes or in the test source PKAT

- Production of photocathodes on different substrates

- Analysis of the spectrally resolved quantum yield

- knowledge of vacuum technology, semiconductor physics and accelerator physics will be taught