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 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 Corrections Drift Points Drift points taken every 20 mins during runs Correct all ADC values back to a reference point for each strip end to remove gain drift Correction 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/( 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

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 End Write Strip-to-Strip Normalisation Factors to Database: Users can obtain charge in Normalised “CalDet” ADC units Typically 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 muons 20 o Vertical Angle Cut  Cosmic muon sample

Results using Cosmic Muons Light output in NPEs at 23 o C: Green: 3.6 pes Clear: 4.5 pes Light output variations: Green: 13.0% Clear: 16.4%

Aside: Gains Gains Green: 75 ADCs Clear: 75 ADCs Width Green: 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 Hits Summed Corrected ADC Dist for electron events narrows slightly <1% Corrections “washed out” by summing

Scintillator Strip Response Short 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 Response Long 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 runs Light 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 muons Not 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 muons Can see that…

Use high energy, straight muons to measure plane alignment Fix hit in first plane of detector (for each orientation), fit straight line to rest of track  alignment wrt first plane Plot (expected hit strip – actual hit strip) for each plane: Alignment

Offsets w.r.t. first plane ================= Even: Mean ~ 0.1cms RMS ~ 0.2 cms Odd: Mean ~ cms RMS ~ 0.4 cms

Summary & Future CalDet Calibration running within Framework Scintillator Light Output Variations Understood T7 running unable to shed light on MC/T11 Range differences Add Attenuation Corrections Compare Alignment Measurements with Offline Package – use misalignment info during track reconstruction/path length & attenuation corrections