Muons at CalDet Introduction

1. Muons at CalDetIntroduction • Track Finder Package • ADC Corrections • Drift Points • Path Length • Attenuation • Strip-to-Strip Calibration • Scintillator Response with • Temperature • Time • Off Beam Energy Muons • Alignment

2. 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

3. Event Display - Muon

4. Event Display - Pion

5. Event Display - Electron

6. ADC CorrectionsDrift 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

7. 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

8. Attenuation – Uncorrected ADC Versus Position along Strip

9. Attenuation – Characterization (Ryan Nichol)

10. Attenuation – Corrected ADC Versus Position along Strip

11. Attenuation – Corrected ADC Versus Position along Strip

12. 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

13. Results using Cosmic Muons • Angular Distributions of non-beam runs clearly show contribution from PS muons • 20o Vertical Angle Cut  Cosmic muon sample

14. 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%

15. Aside: Gains • Gains Green: 75 ADCs Clear: 75 ADCs • Width Green: 10% Clear: 10%

16. 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

17. 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

18. 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

19. 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 runs • Light output appears to be stable on this timescale

20. 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

21. Off Beam Energy Muons • Look at distribution of vertical strip hit in first plane vs horizonal angle for through-going muons • Can see that…

22. Alignment • 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:

23. Alignment Offsets w.r.t. first plane ================= Even: Mean ~ 0.1cms RMS ~ 0.2 cms Odd: Mean ~ -0.74 cms RMS ~ 0.4 cms

24. 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