1. TIMEPIX TESTBEAM TELESCOPE FOR AIDA
Paula Collins – LHCb
Slides taken from Richard Plackett
VERTEX 09 presentation

2. Medipix2
Single photon counting readout provides low noise, high contrast images with very high dynamic range
55um pixel matrix (256 by 256) reading Si, 3D, CdTe, GaAs sensors
Configurable ‘shutter’ allows many different applications

3. Timepix Timepix is a derivative of Medipix2
Addition of a global clock (up 100MHz) which is propagated to every pixel
Originally conceived for GEM foil detectors
The clock can be used for Time of Arrival (ToA) and Time over Threshold (ToT) modes.
Threshold
Time of Arrival Mode
Counts from passing threshold to closing shutter
Allows accurate timing of hits in individual pixels

4. silicon edge just 7 mm from beam!
LHCb VELO Upgrade
Closest LHC detector to the beam
Currently 21 perpendicular two sided strip planes
Upgrade to strip or pixel system
Upgraded device must withstand 0.8x1016 neq (400 MRad TID)
silicon edge just 7 mm from beam!

5. Potential Module Design
Silicon (1-3 pieces) 55x55 mm pixels, 800 mm pixels in areas under chip periphery
Diamond thermal plane with
cutouts immediately above TSV regions
10 Timepix chips
(periphery indicated in white)
Cooling channel
Power strips and
signal routing area
With a Pixel VELO we can have a low scattering module with high resolution and no strip detector ambiguities

6. Prototype Strip Developments
Prototype Strip detectors with 40 MHz readout being built at USC with support from Glasgow
Order being finalised with Hamamatsu for n-in-p prototypes
These will need testbeam evaluation

7. Urgent and continuing testbeam needs
Required to demonstrate suitability for tracking
Measure efficiency and resolution
Provide information for VELOPIX design
3 testbeams at CERN SPS with 120GeV Pions
June: as Medipix Group to test Telescope concept
July: Running parasitically from CMS SiBit telescope
August: Running parasitically from EUDET/LCFI testbeam
Significant improvements to telescope design at each testbeam

8. Timepix Telescope 4 Timepix, 2 Medipix planes in telescope
Symmetric positioning of planes around Timepix DUT
Telescope planes mounted at nine degrees in x and y
DUT position and angle controlled remotely by stepper motors
Measurements of resolution with angle, threshold, sensor bias, 3D sensor and timewalk

9. Angled Planes to Boost Resolution
Hits that only affect one pixel have limited resolution (30um pixel region)
Angling the sensor means all tracks charge share and use the ToT information
55um
300um
10o
Timepix (ToT) tracked position vs cluster reconstructed position

10. Results – Resolution Vs Track Angle
Rotation about Y axis
2.5um Estimated track contribution to residual
PRELIMINARY: UNCALIBRATED DATA!!
The tracking uncertainty of the telescope around 2 um (and falling)
40 million tracks acquired during 2 weeks running

11. Results – 3D Sensors Efficiency Glasgow double sided CNM sensor
Perpendicular particles passing through a doped hole will deposit less charge in the silicon
The sub-pixel resolution of the telescope allows us to see the efficiency losses due to the anode and cathode holes in the silicon.
Special acknowledgement to Marco Gersabeck who produced this plot and the 3D group at Glasgow who provided the sensor

12. Next step: incorporate new readout system
high REsolution Large Area X-ray Detector
Designed to tile large areas, currently PAN and NIKHEF flavors due to parallel FPGA development
~0.15 kHz readout over ethernet
75,000 tracks per second very reasonable goal for telescope
Prototype (PAN) already functional, final delivery ~6 months

13. Upgraded Timepix Telescope Proposal
New Readout
New Readout
Timing Unit
Timing Signals collected by a timing unit provide flexible software synchronisation
LHC readout board
Telescope arms and timing unit read back to PC via Ethernet or USB 2.0

14. New ‘Single’ PCBs
Data IO – Backward compatibility with current chipboards
Serial IO – connecting boards as a ‘quad’ to be read out together
Sensor Bias – moved to a more convenient place
On board voltage regulators to ensure stable operation
Sutter Output – An easy connector for monitoring and measuring the actual shutter signal
Cutout behind chip to reduce scattering
Mounting Holes to accurately position chipboard
Chip positioning guides to ensure accurate mounting

15. Match to AIDA proposal
The telescope is designed for a staged implementation. The first stage upgrade will build on what was achieved in the summer. The main characteristics are
First Stage
Time stamping to 1ns
Track extrapolation precision to ~ 1 micron
data rates up to 75,000 tracks per second
Automatic integration for testing of 40 MHz electronics
Sensitive area 1.4x1.4 cm
Second Stage
Time stamping to ps
Increase x 4 active area

16. Match to AIDA Proposal The deliverable:
Standalone telescope arms available on short timescale
Ethernet readout
capable of independent operation
At a later stage Control and timing unit to synchronise with DUT, scintillators, etc.
Cheap system designed for testing of 40 MHz electronics
Efficiency and resolution key primary goals
Guarantee that the DUT is live during the telescope readout (this was a headache for the EUDET system)
Resolution is suitable for LHC needs
Telescope would be CERN based, but available to test any system
successfully used at SPS already
available for FEI4 testing, strips etc.
Readout software based on PIXELMAN plus plugins
Very intuitive and easy use
Compatible with future EUDET integration

17. Complementarity to EUDET
Timepix arm can be eventually integrated with EUDET
Development is ~ 15 months and a rough estimate, once the system is designed and built, to reproduce each arm is CHF 20,000
Staged development means that telescope arms will be continuously available from now to completion
Builds gradually on previous success
Support required for development of key items
New PCB
Timing and control unit
mechanics
Software (~ 3 months)
Plugs the gap between what is needed in the immediate future for LHC prototyping and the final EUDET implementation, which also includes ILC requirements