Radiation Tolerance of Programmable Voltage Supply and High Galvanic Insulation Readout Electronics Used by CERN’s LHC Cryogenics

Two new types of electronic cards have been tested in CERN's CHARM irradiation facility. The cards are a complete redesign of a programmable voltage power supply and a revision of a conditioning card used for resistance temperature sensors. The power supply is adjustable between 0 to 60 Vdc and 0 to 4 A; in the ac mode power is adjusted by using a Pulse Width Modulation technique with 230 Vac and 6 A as maximum ratings. The design is based mostly on Commercial Off The Shelf (COTS) integrated circuits that were individually qualified and selected with a TID withstand level target of 1 kGy(Si). The conditioning card is designed to provide galvanic insulation for the temperature sensors that are referred to the LHC magnets power supplies. These cards are mainly located in low radiation areas where Single Event Effects (SEE) can be problematic, the new design mitigates the SEU susceptibility and is capable of withstanding more than 2.5 kV on individual high voltage tests. The card foresees the use of either commercial or rad-hard voltage regulators in order to increase the TID lifetime.