From EP-DT-FS group we got the following news regarding humidity sensors:
- Honeywell HIH-4000 (datasheet here) to be readout using a raspberry pi would require a similar board as the one used currently to readout the gas flow
- Other sensors by "sensiron" (here) to be understood if they can be used since it was reported by some company that it could interact with SF6
In any case we have to find a "smart" way to install those sensors inside a gas tight box to be inserted in series to the gas lines
For what concerns the measurements of the leakage current there is no news at the moment, we are still looking into it