Performance Analysis of LGAD Sensors for the CMS MIP Timing Detector at the HL-LHC
HL-LHC 환경에서의 CMS MIP 타이밍 검출기용 LGAD 센서 성능 분석
- 주제(키워드) 도움말 HL-LHC , CMS , MTD , ETL , LGAD , irradiation , test beam , radiation damage , time resolution
- 발행기관 국립강릉원주대학교 일반대학원
- 지도교수 도움말 Minsuk Kim
- 발행년도 2025
- 학위수여년월 2026. 2
- 학위명 석사
- 학과 및 전공 도움말 일반대학원 물리학과
- 실제URI http://www.dcollection.net/handler/kangnung/000000012336
- UCI I804:42001-000000012336
- 본문언어 영어
초록/요약 도움말
At the High Luminosity-LHC (HL-LHC), roughly 200 pile-up interactions occur simultaneously in each bunch crossing, creating substantial spatial and temporal overlap that complicates event-reconstruction. To address this challenge, the CMS Phase-2 upgrade implements the MIP Timing Detector (MTD), whose Endcap Timing Layer (ETL) uses Low-Gain Avalanche Diode (LGAD sensors to deliver 30–40 ps timing resolution. Because the ETL relies on LGAD sensors and will face integrated fluences up to approximately , pre- and post-irradiation evaluation is required. In this study, LGAD sensors were irradiated with 15 MeV and 13.5 MeV protons at KOMAC and tested at the CERN SPS H6 beamline. Unirradiated sensors met the required performance, whereas irradiated devices showed fluence-dependent degradation. These results identify the practical operating limits of LGAD sensors under HL-LHC conditions and offer essential guidance for future LGAD-based timing detector development.
more목차 도움말
Ⅰ. Introduction 1
Ⅱ. Technical Background 3
1. MIP Timing Detector 3
2. LGAD Sensor Structure 7
3. LGAD Performance Metrics 9
1) Signal Formation in LGAD 11
2) Collected Charge 12
3) Time Resolution 14
(1) Sensor Contributions 15
(2) Front-End Contributions 17
4. LGAD Temperature Effects 17
5. Radiation Damage Mechanisms 18
1) Non Ionizing Energy Loss 18
2) Acceptor Removal Effect 20
3) LGAD-Specific Acceptor Removal Effect 22
4) Neutron vs Proton Damage 24
(1) Defect Production : Neutrons vs Protons 24
(2) Experimental observations 25
(3) Implications for NIEL scaling 25
Ⅲ. Irradiation and Test Beam Experiments 26
1. Proton Irradiation at KOMAC 26
1) Irradiated Sample 27
2) Proton Fluence Estimation 29
3) Irradiation Setup 32
4) Irradiation Procedure 35
5) Irradiation Campaign History 37
(1) Campaign 1-3: 15 MeV 37
(2) Campaign 4: 13.5 MeV 38
2. CERN SPS Test Beam 40
1) Setup 40
2) Experimental procedure 44
Ⅳ. Data Analysis Method 47
1. Event Selection 47
2. Collected Charge Calculation 49
1) Charge definition 49
2) Integration window 50
3) Numerical integration 51
4) Charge-distribution fit 53
3. Time Resolution Calculation 54
1) UFSD-K2 Calculation 56
2) HPK5 Calculation 56
3) UFSD-K1 Calculation 57
Ⅴ. Results 58
1. Sensor Test result 58
1) Collected Charge 60
2) Time Resolution 60
2. UFSD-K1 irradiation result 61
Ⅵ. Conclusion 64
