Nasr, Amgad: Space charge effect measurements for a multi-channel ionization chamber used for synchrotron radiation. 2012
Inhalt
- Abstract
- Zusammenfassung
- Contents
- Chapter 1 Introduction
- 1. Introduction
- 1.1. K-edge digital subtraction imaging:
- 1.2. Detector geometry
- 1.3. Detectors characteristics and limitations:
- 1.4. Time structure
- Chapter 2 Theoretical background
- 2. Introduction
- 2.1. Basic principle
- 2.2. Pulsed shape
- 2.2.1. The interaction position near the cathode
- 2.2.2. The interaction position near the anode
- 2.2.3. The interaction position in the center
- 2.3. Space charge effect
- 2.4. Drift velocity
- 2.5. Recombination
- 2.6. Diffusion
- 2.7. Repulsion
- 2.8. Signal formation
- Chapter 3 Numerical simulation
- 3. Introduction
- 3.1. Chamber geometry
- 3.2. Simulated synchrotron photon flux spectrum
- 3.3. Absorption and calculation
- 3.4. Applied electric field
- 3.5. Drift velocity of electrons
- 3.6. Drift velocity of ions
- 3.7. Charge movements
- 3.8. Recombination
- 3.9. Chopper system for the time resolved measurements
- 3.10. Simulated output signal
- 3.11. Simulation flowchart:
- Chapter 4 Chamber design
- 4. Introduction
- 4.1. The Multi-channel ionization chamber design
- 4.2. Readout electronics
- 4.2.1. Current to voltage converter
- 4.2.2. Differential line driver
- 4.2.3. Differential line receiver
- 4.3. Noise measurement with styroflex capacitors
- Chapter 5 Experimental setup
- 5. Introduction
- 5.1. Setup 1. X-ray spectrum
- 5.2. Setup 2. Linearity and saturation current measurement:
- 5.3. Setup 3. Position resolution measurement:
- 5.4. Setup 4. Time response measurement
- Chapter 6 Results and analysis
- 6. Introduction
- 6.1. X-ray spectrum
- 6.2. Linearity
- 6.3. Saturation current
- 6.4. Position resolution measurement:
- 6.5. Space charge effect
- 6.5.1. Measurement with ArCH4 gas mixture
- 6.5.2. Measurements with Nitrogen gas
- 6.5.3. Residual effect
- 6.6. Comparison measurements with simulation
- Chapter 7 Discussion and conclusion
- 7. Space charge effects
- 7.1.1. Ions density distribution
- 7.1.2. Electron density distribution
- 7.1.3. Electric field distribution
- 7.1.4. Distribution of electrons and ions drift velocities
- 7.2. Conclusion and outlook
- 7.3. Summary
- Appendix A
- Appendix B:
- Reference:
- Acknowledgement