A Testing System For The LHCb Outer Tracker High-Voltage Boards

LHCb is one of the four physics experiments at CERN's Large HadronCollider(LHC). In the LHCb Outer Tracker Front-End Electronics, the high voltageboards hold the high voltage capacitors which distribute high voltage to the strawtubes and read signal out. The traditional high voltage boards place the high voltagecapacitors on the surface, so the spark on the high voltage capacitors caused by thevapor or dust becomes a very important reason that leads to the detector's instability.The high voltage capacitors in the LHCb experiment are buried into the high voltageboards to reduce the room they occupy and the influence to the leakage current fromthe environment such as temperature and humidity. Because of the un-normalproduction procedure, they are very easy to be hurt. Tiny split will come into beingwhen jointing and they are too tiny to be detected at beginning by normal electrictesting method. Once produced, the split will grow slowly and leads to theinvalidation after a term.1950(including 10% for spare) high voltage boards are needed, serving morethan 50000 channels of detectors. These boards should be tested strictly before theyare mounted into the front-end electronics box, monitoring the capacitor parameterssuch as leakage current and capacitance during burn-in and thermal cycling under2500V high voltage. Because of the huge number of the boards and 32 capacitors ineach high voltage board, an automatic testing system is needed instead of testing themmanually.According to the experiments on prototype of the high voltage board, this articleis mainly to design a testing system for high voltage boards, and verify theperformance by some experiments, then gives out the system calibration scheme andtesting solution.