February
Picture of the Month - February 2019
Here you see current insights into the research of the LaMa groups. A collection of the former pictures can be found in the Gallery.
Increased quantum efficiency of photo multiplier tubes – materials science meets Quarks and Co
In the short wavelength region, the quantum efficiency (QE) of photo multiplier tubes is limited by the transparency of the window material. In order to increase this efficiency, wavelength-shifting (WLS) films consisting of organic molecules which absorb light in the UV-region but re-emit photons in the visible range of the electromagnetic spectrum were optimized in the Dürr-labs. They were then applied on multi anode photo multiplier tubes (MAPMT) which are used in the Ring Imaging Cherenkov (RICH) detectors of the HADES and CBM experiments at GSI/FAIR. Most recently, 48 of the coated MAPMTs were installed during an upgrade of the HADES detector which is now taking the first data.
The photograph (G. Otto, GSI) shows most of the 428 MAPMTs of the HADES-RICH detector with the inner 48 MAPMTs being covered by a WLS film. The increased QE is shown in the graph which we published most recently in collaboration with the CBM-/HADES-RICH groups [Adamczewski-Musch et al., Nucl. Instrum. Meth. A (2019). DOI: 10.1016/j.nima.2019.01.093].
This picture was submitted by Prof. Dr. Michael Dürr.