ProtoDUNE-SP Purity Monitor Operation Jianming Bian, Isloo Seong (UCI) Casandra Morris, Andrew Renshaw (UH) Stephen Pordes (FNAL)
ProtoDUNE-SP Purity Monitors Top PrM M. Adamowski et al., JINST 9, P07005 (2014). Middle PrM Individual PrMon: Xe flash lamp light source • • Al-Ti-Au photocathode for drift Bottom PrM electron generation Cathode/anode gates for charge • screening at readout Internal cable shields tied to • PrMon cage and flange
ProtoDUNE-SP Purity Monitors PrM Electronics Xenon Light Source Top PrM Top Flange Middle PrM Bottom PrM Fiber Protector
Purity Monitor Operation • July 23, purging started • Turned on purity monitors at ~15:50 pm, July 25, in Ar Gas • August 7, Start to fill LAr • August 21, Bottom PrM submerged by LAr • August 31, PrM anode signals reduced in size considerably due to filters beginning to saturate, regenerate filter • September 6, top PrM submerged by LAr • September 19, start to recirculate LAr
July 25, in Ar Gas, -30V,300V
After cooling down (Aug 3), -30V,300V
August 21, Bottom PrM submerged by LAr,-300V,3000V first LAr signal, lifetime = 45 us 45us,
August 31, PrM anode signals reduced in size considerably due to filters beginning to saturate, regenerate filter e-lifetime dropped from 45us to ~30us, anode signal significantly reduced
Use cathode signal to estimate lifetime
Use cathode signal to estimate lifetime
September 6-19, before LAr recirculation In GAr
Summary • We see cathode and anode signals on the three purity monitors • All three purity monitors and the xenon light source work properly • Purity monitor DAQ works well • Found filter saturation at early stage • Start to monitor purity during LAr recirculation
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