WG-C, August 7, 2007
Present: Kuchler, Huedem, Gaddi, Herve, Parker, Burrows, Damerell, Enomoto, Asiri, Oriunno, Markiewicz, Garbincius, Lackowski, Sugimoto, Seryi (+possibly other colleagues)
Emil Huedem presented brief list of HVAC requirements implemented at CDF. (attached)
In particular, +-1 deg C is required.
Comments: T stability needed to keep detector calibration stable.
CMS comment: also plan to keep +-1deg C, and also worry about humidity: require to keep Dew point below 13 deg C anywhere in the cavern, since there are cold pipes at -30 deg C, they are insulated, but there were concerns about condensation.
Discussion whether there is difference for HVAC and heat for detector on beam line and off beamline.
Comments from CERN colleagues: in CMC have decided that each source of heat on the detector will have the heat intercepted by water. In this case there is no difference with detector ON or OFF.
Important to keep both detectors (on beamline and off beamline) at the same temperature.
Discussed air T stratification in long vertical shaft. In CMS in addition to the top cover there is metallic structure at the bottom that block the shaft.
Discussed temperature stability of detector iron. The large mass of iron has very long time constant. In CMS have water pipes connected to the yoke to keep it temperature to about 18 deg C, this is a better way than to control it via air temperature.
Next week: identify what is in IR cost now.