The ATLAS Pixel Detector

1. The ATLAS Pixel Detector A CERN Summer Student’s-Eye View Tom Whyntie University of Cambridge

2. SLAC, USA Cerne Abbas Man, UK Stone Henge, UK White Horse, UK Tom Whyntie University of Cambridge

3. Where is the Pixel Detector? 1.3m long, 33cm diameter, 1.7m2 active detector area Tom Whyntie University of Cambridge

4. Pixel Detector Requirements • Spatial resolution: 10mm • Temporal resolution: 25ns • Radiation hardness: 3 x 1014 cm-2 NE per year Tom Whyntie University of Cambridge

5. Silicon Detectors – The Basics Extra holes (III) p-type Silicon Extra electrons (V) n-type Silicon Tom Whyntie University of Cambridge

6. Silicon Detectors – The Basics p-type Silicon Depletion Zone Induced Electric Field n-type Silicon Tom Whyntie University of Cambridge

7. Applied Voltage Silicon Detectors – The Basics p-type Silicon Depletion Zone Active Detector Area n-type Silicon Reverse biased pn-junction Tom Whyntie University of Cambridge

8. Silicon Detectors – The Basics p-type Silicon Depletion Zone Applied Voltage Active Detector Area n-type Silicon Tom Whyntie University of Cambridge

9. To readout Silicon Detectors – The Basics p-type Silicon Depletion Zone Applied Voltage Active Detector Area n-type Silicon Tom Whyntie University of Cambridge

10. The Pixel Module 2D array of sensors Module Controller Chip (MCC) Front End (FE) electronics chips: 160 x 18 = 2889 pixels per chip 16 chips per module Circuit board Silicon sensor “Bump bonds” 1744 modules  ~ 80 million pixels! Tom Whyntie University of Cambridge

11. What Does a Pixel Module Need? High Voltage (HV) supply – depletes the silicon  600V Data Opto board supplies  2 V Temperature sensor resistor (NTC) readings For Interlock Low Voltage (LV) supplies – powers the FE electronics  2.5 V Tom Whyntie University of Cambridge

12. $ $ $ $ $ $ $ $ My Project – The Problem • Pixel modules are expensive • Supply kit can be badly designed / made • Need a “module substitute” • Number of supply lines: ~7500 Test Box Tom Whyntie University of Cambridge

13. My Project – The Solution Tom Whyntie University of Cambridge

14. HV Power (VDET) ISEG Power Supply High Voltage (HV) HV PP4 PP2 HV Wiener Power Supply LV Power VDD, VDDA Low Voltage (LV) LV PP4 Regulator Board VVDC Sense lines LV Opto Power Opto Power • PP3 • OPTO • BBM • BBIM SCOLink Power Supply VISET, VPIN, OPTO_RST NTC / Optoboard NTC, NTC_OPTO NTC lines Interlock NTC Opto Cabling: Type IV Type III Type II The Implementation Tom Whyntie University of Cambridge

15. HV HV HV The Implementation 26 x VDET 2 x SAFE 2 x DRAIN DCS HV Test Box 26 x VDET PC AWG26 (from LEMO cable) GPIB 13 x VDET 26 x VDET 2 x SAFE 2 x DRAIN Keithley 7708 40 Channels HV Test Box 13 x VDET AWG26 (from LEMO cable) Keithley 2700 Scanning DMM Max 300V 26 x VDET 2 x SAFE 2 x DRAIN 26 x VDET HV Test Box Keithley 7708 40 Channels AWG26 (from LEMO cable) AWG22 (for7708 screw terminals) Tom Whyntie University of Cambridge

16. LV NTC/ Opto The Implementation 2 x Keithley 7166 2 x 1 x 10 Channels Keithley 7001 Switching Matrix Agilent N3300A Active Load Mainframe 7001’s, Agilent and Scanning DVM connect to PC (via GPIB), which then connects to the DCS… • Challenges: • Physical • Connections • Test Conditions • Simulation • Automation 7 x VDD 7 x VDDA 1 x VVDC AWG26 (LEMO cable) Resistors (Type 0 and 1 cables) 5 x Agilent N3302A: Load Modules 7 x SENSE_VDD 7 xSENSE_ VDDA 1 x SENSE_VVDC 13 x NTC 2 x NTC_OPTO AWG22 (recommended) 13 x NTC 2 x NTC_OPTO 6 x Opto Voltages Keithley 7011S 4 x 1 x 10 Channels Keithley 7001 Switching Matrix NTC/Opto Test Box 2 x VISET 2 x VPIN 2 x OPTO_RST Scanning DMM AWG26 (LEMO cable) Tom Whyntie University of Cambridge

17. Actual Use of the Test System Tom Whyntie University of Cambridge

18. Conclusions • Outcomes for CERN: • Pixel Services Test System designed • Will be implemented in near future;  At least the Pixel Detector will work • Outcomes for me: • Not massively physics-based… • But learnt a lot about everything else. • Appreciation of the scale of CERN • Engineering effort, collaborations, etc. Tom Whyntie University of Cambridge

19. Tom Whyntie University of Cambridge

20. Thanks for listening! • Acknowledgements: • CERN • The Summer Student team – thanks for a great programme! • ATLAS Pixel Detector Group • Kevin Einsweiler (LBNL), Project Leader • Sidney Sussex College, University of Cambridge • And last, but not least… • Markus Keil (CFTP Lisbon), Summer Project Supervisor Tom Whyntie University of Cambridge