Upgrade of the HADES RICH photon detector and first performance analyses / vorgelegt von Jörg Förtsch. Wuppertal, 28. Juli 2021
Inhalt
- Abstract
- Contents
- 1 Introduction
- 1.1 Motivation for this thesis
- 1.2 Outline
- 1.3 The HADES spectrometer
- 1.3.1 START VETO detectors and the target area
- 1.3.2 Mini Drift Chambers and the magnet
- 1.3.3 TOF and RPC
- 1.3.4 Trigger setup and data acquisition (DAQ)
- 1.4 Cherenkov radiation and RICH detectors
- 1.5 The HADES RICH
- 1.6 Sources of electrons relevant in following analyses
- I Testing the HADES RICH hardware by means of laboratory measurements
- 2 The upgraded photon detector of the HADES RICH
- 2.1 The H12700 MultiAnode PhotoMultiplier Tube
- 2.2 Testing procedure and the test bench
- 2.3 Long term behavior of MAPMT characteristics
- 2.3.1 Explanation of the analysis
- 2.3.2 Time stability of dark-rate
- 2.3.3 Time stability of afterpulse-probability
- 2.3.4 Time stability of gain
- 2.3.5 Time stability of photon detection efficiency
- 2.3.6 Summary
- 2.4 Development of H12700 MAPMT characteristics over production time
- 2.4.1 Explanation of the visualization method
- 2.4.2 Dark-rate versus production time
- 2.4.3 Efficiency-Index versus production time
- 2.4.4 Effective area versus production time
- 2.4.5 Homogeneity/skewness versus production time
- 2.4.6 Gain versus production time
- 2.4.7 Afterpulse-probability versus production time
- 2.4.8 Summary
- 2.5 MAPMT grouping for the HADES RICH
- 3 Software framework for DIRICH control and first measurements
- 3.1 Introduction to the DiRICH readout chain setup
- 3.2 Procedure for baseline determination
- 3.2.1 Impact of input capacitance on the noise band width
- 3.2.2 Impact of the DC/DC converter on the noise band width
- 3.2.3 Noise band width and baseline stability in the HADES RICH
- 3.3 Amplitude spectra from rate scans at varying thresholds
- II Tuning the RICH detector's performance on basis of beam data
- 4 Introduction to the HYDRA analysis chain
- 5 Preparatory Studies
- 5.1 Impact of magnetic stray field on efficiency
- 5.2 Scintillation light from radiator gas and CaF2 window
- 6 Derivation and impact of time and ToT cuts
- 6.1 Basic LE time and ToT cuts
- 6.2 Discussion of features in the LE time vs. ToT spectra
- 6.3 Derivation and analysis of sharp LE time cuts
- 6.4 Summary
- 7 Timing precision of the DiRICH readout chain in HADES
- 7.1 Leading Edge timing precision for narrow bins in ToT
- 7.2 Influence of WLS coating on LE timing precision
- 7.3 Summary
- 8 Using ToT information for background suppression
- 8.1 Uncalibrated ToT sum as proxy for photon multiplicity in single hits
- 8.2 Discussion of ToT spectra on basis of single channels
- 8.3 Deriving a ToT calibration per channel
- 8.4 Calibrated ToT sum as proxy for photon multiplicity in single hits
- 8.5 Summary
- 9 Analytical transformation procedures for the RICH in HADES
- 10 Summary and outlook
- 10.1 Testing the HADES RICH hardware by means of laboratory measurements
- 10.2 Tuning the RICH detector's performance on basis of beam data
- 10.3 Outlook
- List of Figures
- List of Tables
- Appendices
- A Additional figures
- A.1 Additional figures for Chapter 1
- A.2 Additional figures for Chapter 2
- A.3 Additional figures for Chapter 3
- A.4 Additional figures for Chapter 5
- A.5 Additional figures for Chapter 6
- A.6 Additional figures for Chapter 7
- A.7 Additional figures for Chapter 8
- A.8 Additional figures for Chapter 9
- B Detailed explanations
- B.1 Differentiation procedure for integrated rate spectra
- B.2 Procedure to build raw hits from single edges in HYDRA
- B.3 Hit track matching for RICH (photon) hits
- B.4 Estimation on average number of photons per pixel
- B.5 Approximation of the best possible ring matching resolution
- B.6 Detailed derivation of a coordinate transformation xold/yold to xnew/ynew unifying ring radii
- References
- Acknowledgements
- Declaration