Daya Bay RPC Gas System Installation and Commissioning
Daya Bay RPC Gas System Installation and Commissioning Changguo Lu, Kirk Mc. Donald Princeton University (Jan. 2, 2012) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 1
April, 2011 finished EH 1 gas system installation and started commissioning; September, 2011 finished EH 2 gas system installation and started commissioning; November, 2011 finished EH 3 gas system installation and started commissioning. So far, all three systems are working properly, providing Daya Bay RPC gas mixture to all 195 RPC modules (1560 RPCs) plus RPC telescopes. January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 2
RPC Gas System Hardware Installation Gas distribution crates (EH#1) Gas distribution crates January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 3
RPC Gas Distribution Crates Parked at Dwarf Hall of EH#2 RPC gas distribution crates January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 4
RPC Gas System – Gas Distribution Crates (EH#3) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 5
RPC Gas Room in EH#2 Gas chromatograph system and digital bubbler readout PC. Gas cylinder manifold Gas control crates Isobutane gas cabinet January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 6
Digital Bubblers Measure Gas Flow Rate We monitor the bubbling rates for all 2 x 108 gas channels in two near halls and 162 channels in the far hall. There is no channel that is not bubbling, though the bubbling rates are not so uniform. EH 1 bubbling rate and the rate fluctuation The red curve shows rate fluctuation (sigma) for each individual channel, it reflects the variation of their “breathing”. Larger sigma indicates heavier “breathing”. January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 7
Different “Breathing” Behavior among Gas Channels 15 10 5 0 1 11 21 31 41 51 Sample # 61 71 81 91 51 sample # 61 71 81 91 BD 01 C 2 Rate (Hz) These two channels are “breathing” heavily. Rate (Hz) BD 01 C 1 15 10 5 0 1 11 21 31 41 Saturated maximum bubbling rate in digital bubbler 6 4 2 0 1 11 21 31 41 51 sample # BD 01 C 16 Rate (Hz) These two channels are “breathing” lighter. Rate (Hz) BD 01 C 15 6 4 2 0 1 11 January 7 - 10, 2012 21 31 41 51 sample # Daya Bay Workshop, Daya Bay, China 8
EH #1 Bubbling Rate (w/o RPC Modules) To make sure the rate variation among the gas channels is not due to gas flow resistors, we also plot the bubbling rate for these channels without RPCs (which were replaced by short tubes). This plot shows the variation of gas flow resistors among 108 channels. January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 9
EH #2 Bubbling Rate (with RPC Modules) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 10
EH #2 Bubbling Rate (w/o RPC Modules) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 11
EH #3 Bubbling Rate (with RPC Modules) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 12
Gas Chromatograph Analysis of Gas Mixing Ratio (EH#1) Nominal Daya Bay RPC gas mixing ratio is Isob/Ar/R 134 A/SF 6 (4/65. 5/30/0. 5), the GC-tested mixing ratio is stable and quite close to nominal. January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 13
Gas Chromatograph Analysis of Gas Mixing Ratio (EH#3) January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 14
DCS History Plot of the Gas Flow Rate EH #1 Ran out of R 134 A gas, gas system was shut off in this period. October 22, 2011 Presentation to the Do. E 15
History Plot of the Gas Cylinder Weights (EH 1) From the decreasing slope of weight vs. time we can tell the gas consumption rate. Running out of R 134 A gas, gas system was shut off in this period. 16
Summary of RPC Gas System Status The Princeton RPC gas system has been delivered and commissioned within the Daya Bay experiment’s aggressive schedule; So far, all three gas systems are working properly, providing the proper gas mixture and flow rate to the RPC modules; The IHEP gas team lead by Hansheng Sun has made big contributions to the installation and continue to be in charge of daily operations; We at Princeton have been able to monitor the gas system operation remotely. If there is any gas system problem we can communicate with on-site IHEP relevant personal (Mengyun Guan, Qingmin Zhang, Jilei Xu and Zhe Ning) to solve it in time. So far, this has worked out well. We would like to thank Victor Pec and Czech group, Logan Lebanowski, Shih-kai Lin, and many other Collaboration members for their help during the installation and commissioning. Special thanks to LIMs for their strong and efficient support. January 7 - 10, 2012 Daya Bay Workshop, Daya Bay, China 17
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