Output details
15 - General Engineering
Brunel University London
The effect of pulse rate on vacuum phototriodes response and the use of an LED pulser to improve stability
The Endcap Electromagnetic Calorimeter of the CMS detector at the LHC, CERN uses vacuum phototriodes (VPTs), which operate in a 3.8T magnetic field, to detect fast scintillation light from lead tungstate crystals. The response of production VPTs was investigated in three independent studies: one by the author at Brunel. Good VPTs stability is demonstrated with a regime for operating a light pulser that minimises variations in response. A pulser rate of 100Hz is sufficient to stabilise the VPT response to <0.2%. This work was funded by an STFC grant and has led to further support (ST/K001639/1).