Euromedim 2006 :1st European Conference on Molecular Imaging Technology

LHCb calorimeters HV system

10 May 2006, 14:00

1h

Palais du Pharo, Marseille

poster • Electronics, read out, data acquisition Poster session : detection modules and electronics

Speaker

Anatoli Konoplyannikov (CERN, Geneva, Switserland)

Description

The calorimeter system in LHCb aims to identify electrons, photons and hadrons. The system plays also a major role for the first level triggers. All calorimeters are equipped with Hamamatsu photo tubes as devices for light to signal conversion. Eight thousand R7899-20 tubes are used for electromagnetic and hadronic calorimeters and two hundred 64 channels multi-anode R7600 -00-M64 for Scintillator-Pad/Preshower detectors. In the same time in Molecular Imaging applications the similar photodetectors are widely used too. Requirements for the calorimeter HV system • Individual control of each detector channel; • Minimizing the number of the HV cables is desired; • The system has to operate in a radiation hard environment; • Minimizing power consumption is important; • Easy connection to Experimental Control System (ECS); • Optimisation of the overall cost. The calorimeter HV system is based on a Cockroft Walton (CW) voltage converter and distributed on detector control boards connected to ECS by the SPECS serial bus. For the ECAL and HCAL the base of each photomultiplier tube (PMT) is built with a high voltage converter and constructed on individual printed circuit board, using compact surface mount components. The base is attached directly on the PMT. There are no HV cables in the system. A Field Programmable Gate Array (rad-tolerant FPGA) is used as an interface between the ECS and the 200 control channels which are supplied by each high voltage control signal distribution board. The motherboard contains an FPGA with a SPECS interface, which is connected to the Actel HV Control FPGA via a parallel bus. The role of the HV Control FPGA is to distribute signals from the SPECS bus to the electronics mounted on the motherboard and control voltage generation daughterboards. The aim of the presentation is to describe the HV system architecture, some technical details of the electronics implementation and summarize the system performance. The presented safety and very low power consumption HV electronic system for the photomultiplier tubes can be used for various biomedical apparatus.