1. The ATLAS Pixel Detector
Looking at about 15 minutes with questions…
One slide per minute -> ~15 slides (16 inc. title)
But remember, way the way to think about it is to come up with the story first, then work out the visual aids I’ll need, then work the story back around the visual aids…
A CERN Summer Student’s-Eye View
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

2. SLAC, USA White Horse, UK Stone Henge, UK Cerne Abbas Man, UK
As you probably know, this is the SLAC accelerator…
(Click) This might not be so familiar… carved into the hillside
It was an attempt by early British man to
You can see where this is going... (Click) Yeah, that’s right. SLAC is basically the physicist’s way of expressing
It took you Yanks a little longer, but you got there in the end…
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

3. Where is the Pixel Detector?
1.3m long, 33cm diameter, 1.7m2 active detector area
CERN Summer School
15th August 2006
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
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

5. Silicon Detectors – The Basics
Extra holes (III)
p-type Silicon
Extra electrons (V)
n-type Silicon
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

6. Silicon Detectors – The Basics
p-type Silicon
Induced Electric Field
Depletion Zone
n-type Silicon
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

7. Silicon Detectors – The Basics
p-type Silicon
Applied Voltage
Depletion Zone
Active Detector Area
n-type Silicon
Reverse biased pn-junction
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

8. Silicon Detectors – The Basics
p-type Silicon
Depletion Zone
Applied Voltage
Active Detector Area
n-type Silicon
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

9. Silicon Detectors – The Basics
To readout
p-type Silicon
Depletion Zone
Applied Voltage
Active Detector Area
n-type Silicon
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

10. The Pixel Module 1744 modules  ~ 80 million pixels!
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!
CERN Summer School
15th August 2006
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
CERN Summer School
15th August 2006
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
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

13. My Project – The Solution
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

14. The Implementation ISEG High Voltage (HV) PP2 Low Voltage Wiener (LV)
Power Supply
LV PP4 LV
High Voltage
(HV)
ISEG
HV PP4 HV
PP2
Regulator
Board
NTC /
Optoboard
SCOLink
NTC
Opto
PP3
OPTO
BBM
BBIM
HV Power (VDET)
LV Power
Opto Power
VISET, VPIN, OPTO_RST
NTC, NTC_OPTO
Sense lines
VVDC
VDD, VDDA
NTC lines
Interlock
Type IV
Type III
Type II
Cabling:
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

15. The Implementation DCS HV Test Box PC Keithley 7708 40 Channels
26 x VDET
2 x SAFE
2 x DRAIN
DCS
HV Test Box HV
26 x VDET PC
AWG26
(from LEMO cable)
GPIB
26 x VDET
2 x SAFE
2 x DRAIN
13 x VDET
HV Test Box
Keithley Channels HV
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 HV
Keithley Channels
AWG26
(from LEMO cable)
CERN Summer School
15th August 2006
AWG22
(for7708 screw terminals)
Tom Whyntie
University of Cambridge

16. The Implementation Challenges: Physical Simulation Automation
7001’s, Agilent and Scanning DVM connect to PC (via GPIB), which then connects to the DCS…
2 x Keithley 7166
2 x 1 x 10 Channels
Keithley 7001 Switching Matrix
Agilent N3300A
Active Load Mainframe
Challenges:
Physical
Connections
Test Conditions
Simulation
Automation
7 x VDD
7 x VDDA
1 x VVDC
AWG26
(LEMO cable) LV
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
NTC/Opto
Test Box
Keithley 7001 Switching Matrix
2 x VISET
2 x VPIN
2 x OPTO_RST
NTC/
Opto
Scanning DMM
AWG26
(LEMO cable)
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

17. Actual Use of the Test System
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

18. Conclusions Outcomes for CERN: Outcomes for me:
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.
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge

19. CERN Summer School
15th August 2006
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
So, how do you get around this problem?
CERN Summer School
15th August 2006
Tom Whyntie
University of Cambridge