Publication
Monitoring humidity and temperature in silicon-based high-energy physics (HEP) detectors is indispensable but challenging due to space restrictions, radiation, sub-zero temperatures, and strong magnetic fields. This manuscript presents humidity and temperature monitoring systems with radiation compensation suitable for integration in HEP environments. The humidity monitoring system is based on the MK33-W sensor, which exhibits linear output capacitance change with accumulated fluence. The sensor is insensitive to strong magnetic field variations, and its temperature dependence is compensated using the inverse second-degree calibration function. The designed readout circuit is based on commercial off-the-shelf (COTS) components that are not radiation/magnetic field immune and must be placed far away (~100 m) from the sensor. Passive and active shielding methods are applied to minimize the parasitic capacitance introduced by the cables. Furthermore, the readout unit effectively nullifies the sensor internal parasitic resistance. The Pt1000 Resistance Temperature Detector (RTD) is chosen for temperature monitoring due to its high radiation tolerance. The change in resistance of an RTD is equivalent to 2.3 °C after accumulating a dose of 4 · 1016 protons/cm2 which is the highest expected dose in the HL-LHC experiments after 10 years of operation. A cost-effective, embedded-based solution for a massive-temperature readout system that conditions up to 24 RTDs is proposed.