Diamond Detectors for Ionizing Radiation - HEPHY

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CHAPTER 8. DETECTOR GEOMETRIES 54 Figure 8.6: The CMS diamond pixel detector with 125 125 m 2 unit cell size (100 100 m 2 electrodes). The indium pearls, which form the contact in the bump-bonding process, are visible in the close-up to the right. Figure 8.7: The ATLAS diamond pixel detector with 50 536 m 2 cell size.
Chapter 9 Summary The possible application of radiation detectors based on CVD diamond has been demonstrated. Similar to semiconductor detectors such as silicon, the Bethe-Bloch and Landau theories are ecient tools to describe the behavior of diamond detectors. The polycrystalline structure of CVD diamond implies its inhomogeneity. A linear model over the detector thickness describes the relationship between local and average collection distances. This model satises experimental data. High quality CVD diamond is obtained by removing material with poor charge collection properties from the substrate side. The growth process has been successfully applied to grow large area detectors. Excellent progress has been achieved over the past years by the RD42 collaboration. The charge collection distance of diamond has been increased, now reaching 230 m (corresponding to 8300 e) with a sample 432 m thick and slightly more with thicker samples. A compact characterization station was built in Vienna, which has been successfully used for pulse height measurements. Due to my contribution and optimization, it has a very low noise gure (ENC = 270 e). Moreover, I was involved in the pion irradiation of CVD diamond samples, which was carried out by the HEPHY in the autumns of 1995, 1996 and 1997. I made essential contributions in preparation, realization and data analysis including further studies such as the calculation of electric eld distributions in diamond samples. In agreement with the linear model we could show that diamond samples with higher initial collection distance are more aected by irradiation than those with lower d c . Similar, we have demonstrated that the upper (Landau) tail of the signal distribution suers more from radiation than the low signal region, which remains almost unaected. This implies that the eciency of applications with a moderate threshold (a few thousand electrons) will be less aected by radiation than the mean value of the distribution. Furthermore, the radiation hardness of diamond has been demonstrated for all major particles. Simplifying the results of the irradiation experiments, diamond is expected to survive a hadronic uence of at least 10 15 particles cm ,2 , corresponding to the projected charged hadron uence at a radius of 7cm from the vertex in the LHC accelerator at CERN over 10 years. This is ten times more than present silicon detectors allow. Diamond micro-strip detectors were successfully tested with both slow (VA2) and fast (SCT128AHC) electronics. With the best diamond sample available, most probable 55
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Diploma Thesis Diamond Detectors fo
Page 3 and 4: CONTENTS 3 7 Radiation Hardness 37
Page 5 and 6: CHAPTER 1. SYNOPSIS 5 primarily sil
Page 7 and 8: CHAPTER 2. INTRODUCTION 7 Figure 2.
Page 9 and 10: Chapter 3 Material Properties 3.1 G
Page 11 and 12: CHAPTER 3. MATERIAL PROPERTIES 11 Q
Page 13 and 14: CHAPTER 3. MATERIAL PROPERTIES 13 d
Page 15 and 16: Chapter 4 Solid State Detector Theo
Page 17 and 18: CHAPTER 4. SOLID STATE DETECTOR THE
Page 19 and 20: CHAPTER 4. SOLID STATE DETECTOR THE
Page 21 and 22: CHAPTER 5. DETECTOR MATERIAL COMPAR
Page 27 and 28: CHAPTER 6. CHARACTERIZATION 27 6.1.
Page 29 and 30: CHAPTER 6. CHARACTERIZATION 29 and
Page 31 and 32: CHAPTER 6. CHARACTERIZATION 31 Lid
Page 33 and 34: CHAPTER 6. CHARACTERIZATION 33 Figu
Page 35 and 36: CHAPTER 6. CHARACTERIZATION 35 300
Page 37 and 38: Chapter 7 Radiation Hardness 7.1 Ra
Page 39 and 40: CHAPTER 7. RADIATION HARDNESS 39 7.
Page 41 and 42: CHAPTER 7. RADIATION HARDNESS 41 Ca
Page 43 and 44: CHAPTER 7. RADIATION HARDNESS 43 ev
Page 45 and 46: CHAPTER 7. RADIATION HARDNESS 45 2
Page 47 and 48: CHAPTER 7. RADIATION HARDNESS 47 no
Page 49 and 50: CHAPTER 8. DETECTOR GEOMETRIES 49 F
Page 51 and 52: CHAPTER 8. DETECTOR GEOMETRIES 51 S
Page 53: CHAPTER 8. DETECTOR GEOMETRIES 53 i
Page 57 and 58: Acknowledgements First of all, I am
Page 59 and 60: APPENDIX A. ABBREVIATIONS AND SYMBO
Page 61 and 62: APPENDIX A. ABBREVIATIONS AND SYMBO
Page 63 and 64: Bibliography [1] Austrian Academy o
Page 65: BIBLIOGRAPHY 65 [29] A. Hrisoho, Fr
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Diamond Detectors for Ionizing Radiation - HEPHY

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