Purity Monitor Update and Plan Ilsoo Seong, Jianming Bian (UCI) Andrew Renshaw (UH) Nov 27, 2018
<latexit sha1_base64="JP1DYS63el45ciIQr/ghOQ/oLx4=">ACMXicbVBNS8NAFNz4WetX1aOXxSJ40JqIoBeh6MWjgrVCU8tm86KLm03YfRFLyF/y4j8RLx4U8eqfcFsL1taBhWHmPd7OBKkUBl31ZmYnJqemS3NlecXFpeWKyurlybJNIcGT2SirwJmQAoFDRQo4SrVwOJAQjO4O+n5zXvQRiTqArsptGN2o0QkOEMrdSqn53cR3hAHedMJSEUBT2iQ6IdvO3L/jaF63wHf61QiwiLYtdHlhWdStWtuX3QceINSJUMcNapPthwrMYFHLJjGl5bortnGkUXEJR9jMDKeN37AZalioWg2n/cQF3bRKSKNE26eQ9tXhjZzFxnTjwE7GNoAZ9Xrif14rw+iwnQuVZgiK/xyKMkxob36aCg0cJRdSxjXwv6V8lumGUdbctmW4I1GHieXezXPrXn+9X68aCOElknG2SLeOSA1MkpOSMNwskjeSFv5N15cl6dD+fzZ3TCGeyskT9wvr4BuIesWA=</latexit> <latexit sha1_base64="JP1DYS63el45ciIQr/ghOQ/oLx4=">ACMXicbVBNS8NAFNz4WetX1aOXxSJ40JqIoBeh6MWjgrVCU8tm86KLm03YfRFLyF/y4j8RLx4U8eqfcFsL1taBhWHmPd7OBKkUBl31ZmYnJqemS3NlecXFpeWKyurlybJNIcGT2SirwJmQAoFDRQo4SrVwOJAQjO4O+n5zXvQRiTqArsptGN2o0QkOEMrdSqn53cR3hAHedMJSEUBT2iQ6IdvO3L/jaF63wHf61QiwiLYtdHlhWdStWtuX3QceINSJUMcNapPthwrMYFHLJjGl5bortnGkUXEJR9jMDKeN37AZalioWg2n/cQF3bRKSKNE26eQ9tXhjZzFxnTjwE7GNoAZ9Xrif14rw+iwnQuVZgiK/xyKMkxob36aCg0cJRdSxjXwv6V8lumGUdbctmW4I1GHieXezXPrXn+9X68aCOElknG2SLeOSA1MkpOSMNwskjeSFv5N15cl6dD+fzZ3TCGeyskT9wvr4BuIesWA=</latexit> <latexit sha1_base64="JP1DYS63el45ciIQr/ghOQ/oLx4=">ACMXicbVBNS8NAFNz4WetX1aOXxSJ40JqIoBeh6MWjgrVCU8tm86KLm03YfRFLyF/y4j8RLx4U8eqfcFsL1taBhWHmPd7OBKkUBl31ZmYnJqemS3NlecXFpeWKyurlybJNIcGT2SirwJmQAoFDRQo4SrVwOJAQjO4O+n5zXvQRiTqArsptGN2o0QkOEMrdSqn53cR3hAHedMJSEUBT2iQ6IdvO3L/jaF63wHf61QiwiLYtdHlhWdStWtuX3QceINSJUMcNapPthwrMYFHLJjGl5bortnGkUXEJR9jMDKeN37AZalioWg2n/cQF3bRKSKNE26eQ9tXhjZzFxnTjwE7GNoAZ9Xrif14rw+iwnQuVZgiK/xyKMkxob36aCg0cJRdSxjXwv6V8lumGUdbctmW4I1GHieXezXPrXn+9X68aCOElknG2SLeOSA1MkpOSMNwskjeSFv5N15cl6dD+fzZ3TCGeyskT9wvr4BuIesWA=</latexit> <latexit sha1_base64="JP1DYS63el45ciIQr/ghOQ/oLx4=">ACMXicbVBNS8NAFNz4WetX1aOXxSJ40JqIoBeh6MWjgrVCU8tm86KLm03YfRFLyF/y4j8RLx4U8eqfcFsL1taBhWHmPd7OBKkUBl31ZmYnJqemS3NlecXFpeWKyurlybJNIcGT2SirwJmQAoFDRQo4SrVwOJAQjO4O+n5zXvQRiTqArsptGN2o0QkOEMrdSqn53cR3hAHedMJSEUBT2iQ6IdvO3L/jaF63wHf61QiwiLYtdHlhWdStWtuX3QceINSJUMcNapPthwrMYFHLJjGl5bortnGkUXEJR9jMDKeN37AZalioWg2n/cQF3bRKSKNE26eQ9tXhjZzFxnTjwE7GNoAZ9Xrif14rw+iwnQuVZgiK/xyKMkxob36aCg0cJRdSxjXwv6V8lumGUdbctmW4I1GHieXezXPrXn+9X68aCOElknG2SLeOSA1MkpOSMNwskjeSFv5N15cl6dD+fzZ3TCGeyskT9wvr4BuIesWA=</latexit> 2 11/27/18 University of California, Irvine Purity Monitors at NP04 • Three Purity Monitors (PrMs) installed at the different depths • Measure the charges on the cathode and anode, and the time of drifting e- in the PrM • Applied HV on the cathode and anode to drift electrons Top PrM e- lifetime ! is calculated with • Q anode = Q cathode e − t drift / τ Mid PrM • Managing the drift time (t_drift) allows to Bot PrM measure the reliable lifetime in different ranges
3 11/27/18 University of California, Irvine Purity Monitor History at NP04 We are taking data since August 21 st • • We took the data smoothly while filling and recirculating LAr • The Bot PrM seems to have an issue with the electronics At the beginning, the lifetime was 45 us, and On Nov 19 th , we achieved the lifetime 6.3 ms • • To achieve the lifetime a few ms level we apply the transparency correction • PrM system alerted the NP04 system twice which helps to take early action to prevent any potential issues • Filter and recirculation issues
4 11/27/18 University of California, Irvine First Report: Aug. 31 st On August 31 st , the cathode signals are dropped and the anode signals are disappeared • • Before this issue, the lifetime was about 45 us • The filter was saturated, the lifetime was dropped to around 35 us. Issue found recirculation start
5 11/27/18 University of California, Irvine Another Report: Oct. 29 th On October 29 th , PrMs saw the lifetime drop • • Unfortunately, the PrM system had an issue, we couldn’t measure the lifetime for 1.5 days • Once we fixed the PrM system, we measured the lifetime 3 ms dropped from 6 ms • The recirculation pump was off à saved the beam runs beam run beam run
6 11/27/18 University of California, Irvine Transparency Correction • Typically, configure the HV to achieve 100% transparency on the ground-grid • When the QA/QC ratio close to 1, the uncertainty on the lifetime becomes larger à lower HV à longer drift time à lower QA/QC ratio • We change the HV setting à low transparency à lose electrons on the ground-grid • Applied the correction factors to recover the charge lose: first attempt • This new method enables us to measure the lifetime longer than 6 ms 6.6 ms
7 11/27/18 University of California, Irvine PrM Data in DQM • Now the lifetime history plot and results can be found at the DQM webpage: p3s-content.cern.ch/Monitor/PRM/ (this link is only working at CERN) • If you want to access it outside from CERN, please check https://wiki.dunescience.org/wiki/D QM_Shifter_Manual
8 11/27/18 University of California, Irvine Future Plans for DUNE-FD • With the NP04 system, study to receive the trigger signal from the detector to operate the PrMs between the trigger intervals • will enable to do real-time measurement • Design 3 different lengths of PrM to achieve the larger lifetime range • From a few us to > 10 ms • Future PrM system R&D • Study the degradations of photo-cathode and optical fiber for long-term use: 10+ years • Systematic study of transparency correction method • Study electron recombination in LAr for different electric fields
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