muons at caldet introduction
DESCRIPTION
Muons at CalDet Introduction. Track Finder Package ADC Corrections Drift Points Path Length Attenuation Strip-to-Strip Calibration Scintillator Response with Temperature Time Off Beam Energy Muons Alignment. Track Finder. Track each plane orientation separately - PowerPoint PPT PresentationTRANSCRIPT
Muons at CalDetIntroduction
Track Finder PackageADC Corrections Drift Points Path Length Attenuation
Strip-to-Strip CalibrationScintillator Response with Temperature Time
Off Beam Energy Muons Alignment
Track Finder
Track each plane orientation separately
Follow track through each plane of detector by looking for hit strips within a user specified range
No more than 2 hits in any plane on the track
Event Display - Muon
Event Display - Pion
Event Display - Electron
ADC CorrectionsDrift Points
Drift points taken every 20 mins during runsCorrect all ADC values back to a reference point for each strip end to remove gain driftCorrection hidden from end user – procedure fully “framework-ized” at CalDet
Path Length Correction
Average path length for finite strip width:
ds = (ds/dz) . [4.05/(4.05 + dT/dz)]
Calculate path length from local track angles
Attenuation – Uncorrected ADC Versus Position along Strip
Attenuation – Characterization (Ryan Nichol)
Attenuation – Corrected ADC Versus Position along Strip
Attenuation – Corrected ADC Versus Position along Strip
Strip-to-Strip Calibration
Currently only apply Drift and Path Length Corrections to Track Hits (Attenuation to come…)Histogram Double Ended Hits and Find 90% Truncated Means per Strip EndWrite Strip-to-Strip Normalisation Factors to Database: Users can obtain charge in Normalised “CalDet” ADC unitsTypically enough muons to update strip-to-strip corrections each run (to remove temperature variations in strip light output)CandDigit::Reco slow - not feasible so far
Results using Cosmic Muons
Angular Distributions of non-beam runs clearly show contribution from PS muons20o Vertical Angle Cut Cosmic muon sample
Results using Cosmic Muons
Light output in NPEs at 23oC:Green: 3.6 pes
Clear: 4.5 pes
Light output variations:Green: 13.0%
Clear: 16.4%
Aside: Gains
GainsGreen: 75 ADCs
Clear: 75 ADCs
WidthGreen: 10%
Clear: 10%
Calibration Check: Muons
Apply Strip-to-Strip Calibration to All Muon Hits Expect RMS/Mean to decrease by: [(Gain Spread)2 + (Light Output Spread)2]0.5 ~ 25% Green
25% Clear
Calibration Check: Electrons
Apply Strip-to-Strip Calibration to All Electron HitsSummed Corrected ADC Dist for electron events narrows slightly <1%Corrections “washed out” by summing
Scintillator Strip ResponseShort Term Variations
Now have Temperature probe at CalDet! (UTexas)
Measure Fractional Changes in Light Output with Time
Compare with Shifts expected due to Temperature
Scintillator Strip ResponseLong Term Variations
Using Temperature Measurements from HARP experiment (also in PS East Hall) can compare light output from 6 month old cosmic runs with recent runsLight output appears to be stable on this timescale
Off Beam Energy Muons
Looking at Track Range for 2 GeV run:Expect a peak at plane ~55 …Instead seem to get a spread of energies + many higher energy muonsNot useful for understanding MC/T11 Range differences
Off Beam Energy Muons
Look at distribution of vertical strip hit in first plane vs horizonal angle for through-going muonsCan see that…
Use high energy, straight muons to measure plane alignmentFix hit in first plane of detector (for each orientation),fit straight line to rest of track alignment wrt first planePlot (expected hit strip – actual hit strip) for each plane:
Alignment
Alignment
Offsets w.r.t. first plane=================Even:Mean ~ 0.1cmsRMS ~ 0.2 cms
Odd:Mean ~ -0.74 cmsRMS ~ 0.4 cms
Summary & Future
CalDet Calibration running within FrameworkScintillator Light Output Variations UnderstoodT7 running unable to shed light on MC/T11 Range differencesAdd Attenuation CorrectionsCompare Alignment Measurements with Offline Package – use misalignment info during track reconstruction/path length & attenuation corrections