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This presentation outlines the analysis of 188 preproduction tanks to monitor detector performance, focusing on key quantities such as anode and dynode baselines, VEM area, and dynode/anode ratios. The study examines the stability of these parameters over time and temperature variations, identifying peculiar behaviors and compliance with quality assurance specifications. Results indicate issues with some tanks, highlighting the impact of temperature on detector performance and the need for continuous monitoring and recalibration in detector systems.
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David Barnhill UCLA Detector Stability Analysis Using MoRI Data
Motivation • Monitor detector performance of key quantities: • Anode and Dynode Baselines • VEM Area and Area/Peak • Dynode Anode ratio • Detect any peculiar behavior as a function of temperature and/or time • Check Quality Assurance specifications suggested in November meeting
Method • We analyzed 188 preproduction tanks from January to February this year • We used LS Calibration Data (MoRI) • We analyzed RMS over this period for Anode and Dynode baselines and RMS/Mean for Dynode/Anode, VEM Area, and Area/Peak for each tank • We also looked at behavior over time and as a function of temperature • * In the next slides: • Then = September – October 2003 • Now = January – February 2004
Then Now Typical Baselines vs. Time
Then Anode Baseline RMS 3 out of spec – 2.2% Now 45 over 2 channel RMS 15 are due to pedestal readjustments 30 out of spec – 5.3%
Then Dynode Baseline RMS 1 out of spec – 0.7% Now 32 over 2 channel RMS 8 are due to pedestal readjustments 24 out of spec – 4.3%
Baseline RMS vs. Station ID Anode Dynode
Baseline Problems All 6 channels => FE problems? (~10 tanks)
Temperature Coefficients - Baselines Anode Then Now
Temperature Coefficients - Baselines Dynode Then Now
LS VEM Area Then 6 out of spec – 4.4% Now 29 over 5% 11 due to recalib. 18 out of spec – 3.2%
Then Now Tank 205 (Mage) VEM Area PMT 1 seems to be decaying
Temperature – LS VEM Area LS VEM Area Then Now
Temperature Problem • As documented in Bugzilla: • http://bugzilla.auger.org.ar/ • There is a known problem with temperature causing jumps in certain quantities • Tanks 116, 147 and possible 158 and 167 • Problem is known, but cause and solution are unknown
Then Now Tank 147 VEM Area
Then Now Tank 116 VEM Area
Then Now Typical LS VEM Area/Peak vs. Time
LS VEM Area/Peak Then All 3 PMTs in each tank affected 35 over 5% -> 6.2% 2 out of spec – 1.5% Now
Temperature - LS VEM Area/Peak Then Now
Then Now Typical Dynode/Anode Ratio
Then Dynode/Anode 7 out of spec -> 5.1% Now 8 out of spec -> 1.4%
Temperature – Dynode Anode Ratio Then Now
Then Now Tank 128 (Vatly) Dynode/Anode No entries in bugzilla
Then Now Dynode/Anode Spiky Behavior - Gone
Quality Assurance Specifications THEN NOW
Stability Conclusions • Pedestals: • All due to ~10 tanks with varying pedestals on all 6 channels • Area/Peak: • All 3 PMTs in a tank affected when one goes bad ~13 tanks • Statistics looks bad, but roughly divide 6.2% by 3 = ~2% problem • Dynode Anode ratio is more consistent and stable, 3 PMTs with bad D/A problem only • VEM Area • Temperature correlation issues ~7 PMTs • Other problems ~3 PMTs • Tanks with PMTs failing multiple specs: • 102, 193, 214, 262