Humidity and Temperature measurement in the ID volume A. Robichaud Véronneau, Richard Brenner, Didier Ferrère, Steve McMahon...
Outline Control of the ID environment ID Sensors: original, existing and extra About the Sensors Installation and Readout This talk will focus on the ID volume, not on the SCT. For more details about SCT humidity measurement, see S. D'Auria's talk in SCT plenary 2
ID environment Control of the dew point inside the ID volume is crucial for commissioning (avoid condensation on cables and connectors) New installation plan will require new ways of controlling the humidity Retrofitted Sensors > Gain experience about our ignorance... Will be important to monitor this carefully during M5 3
ID Sensors location (1) Originally, 18 Xeritron sensor+ntc 'packages' planned to be installed at various locations in the cryostat (see next slide): 2 packages at z=0 (top and bottom) [2a] 4 packages in the heat spreader plates (top and bottom on each side) [2b] 4 packages at PPF1 (135o and 315 o on each side) [2c] 4 packages on the ID end plate (top and bottom on each side) [2d] 4 packages at Pixel PP1 (135o and 315 o on each side) [2e] Of that, 4 are currently installed At z=0, one at the top and and one at the bottom On the cryostat wall (next to PPB1) between Barrel and EC, one on each side We are now left with 14 2 = 12 packages (no more free channels) 4
ID Sensors location (1) c'ted 5
ID Sensors location (2) More measurements were needed in cold areas with active material (earlier this year) 2 Honeywell sensors installed between the SCT HSP (one on each side coupled with a NTC) 1 Honeywell sensor installed in a dry air pipe connected to the SCT Barrel on the A side (believed to be an exhaust) These sensors showed us how little we knew about the environment between the HSP. => Need to know more about what is going on where pipes (or heaters) are installed and cables are located! 6
ID Sensors location (3) In view of the revealing/disturbing measurements we made of the HSP environment, new sensors were installed in this area 2 more Honeywell sensors installed between the SCT HSP (on each side) 2 Xeritron sensors installed next to them (on each side) All of these are coupled with NTC. None of these sensors are connected yet, but they will be plugged into the SCT EC PPF1. 7
ID Sensors location (3) c'ted With the far end heater installation, it becomes clear that we need to monitor the humidity differently than planned originally for the ID. 6 Xeritron sensors per side will be installed (if PPF1 accessible) 2 Honeywell sensors per quadrant per side will be installed The goal is to use these sensors to monitor the HEX, the heaters and the pipes leading to/coming from them. All these sensors will be coupled with NTCs. 8
ID Sensors location (3) c'ted Preliminary installation plan for the new ID sensors (to be installed): Cryostat Side view (not to scale!!) Honeywell Xeritron Hex TRT Hex Heaters Heaters SCT Heaters Heaters Hex Hex 9
What about the sensors? Hygrometrix Xeritron (from datasheet and observation) Radiation hard sensor made of organic and inorganic crystals Slow response on decreasing humidity but fast on increasing humidity Good linearity (+/ 2% over the full range) Accuracy: +/ 1 3% (including linearity) Honeywell HiH 4000 (from datasheet and observation) Non radiation hard sensor made of thermoset polymer capacitive sensing element Fast response on changing humidity Sensible to electrical and mechanical damage Accuracy: +/ 3.5% 10
Dew Point Each humidity sensor should be coupled to a thermistor to make a correct calculation of the dew point. T dp = (((17.08085*T)/(234.175+T)+ln(RH/100))*234.175)/(17.08085 ((17.08085*T)/(234.175+T)+ln(RH/100))) Accuracy The dew point accuracy is driven by the humidity accuracy and does not depend significantly on temperature At very low humidity, with an accuracy of 3%, crude calculation gives up to 30 C error on dew point but the calculated value being so low, it is still way inside the acceptable range. e.g. T=0 C, RH=0.1+/ 3% gives T dp = 67.5 +/ 28 C 11
DCS data All the ID sensor presented here are routed through the SCT DCS Envr hardware readout. The raw data (voltages) from the ELMB are converted to temperatures and humidities (with proper calibration) in the SCT DCS Envr OPC server. Then, the SCT DCS sends this information to the ID DCS Envr project (using scattered project connection). Dew Point calculation should be done on the ID side. The ID DCS Envr project will (in the near future) take care of archiving this data to the Oracle DB (currently done in the SCT DCS). 12
Conclusions The ID environment is already partially monitored for humidity (around the SCT Barrel) The repositioning of the heater and the experience of cooling operation required a change in humidity sensor locations (want to know what happens next to the Hex/heaters) The new sensors are to be installed and/or connected before M5 and will be integrated in the software right after their connection Careful monitoring of these new sensors in cool operations will be extremely important for the SCT and the ID in general 13