Using the EUDET pixel telescope for resolution studies on silicon strip sensors with fine pitch Thomas Bergauer for the SiLC R&D collaboration 21. May.

Using the EUDET pixel telescope for resolution studies on silicon strip

sensors with fine pitch

Thomas Bergauerfor the SiLC R&D collaboration

21. May 2008

Aim of the effort

The goal of this testbeam:• Evaluate the best strip geometry of silicon strip sensors

with 50 micron pitch to achieve the highest possible spatial resolution

• For this purpose we are using a dedicated mini sensor with different zones, each with a different strip geometry:– Different strip widths– 0, 1 or 2 intermediate strips

• We are using the fine resolution of the EUDET pixel telescope to get high precision tracks to determine the residuals for our DUTs [Devices under Test]

3

DUT Sensors

Last sensor order at HPK from SiLC collaboration contains a multi-geometry mini sensor:

• 256 strips with 50um pitch • 16 zones with 16 strips each• Layout constant within each zone• Strip width and number of

intermediate strips vary between the zones

TESTAC:

DUT Sensors

• DUT sensors have been intensively tested in Vienna, e.g.:

• IV curves on all sensors• CV curves to determine full

depletion voltages– approx. 60V

• Measurement of the interstrip capacitance reveal different values for each zone:– Capacitance scales linearly

with strip width– Different offset for region with

one or two intermediate strips

0 100 200 300 400 500 600 700 800

100n

1µ

10µ

curr

en

t

voltage

01 02 03 04 05 06 07 10 12 13 17 19 20 21 23 24 26 27 28 29 30 31 32 34 35 36 37 38

DUT Module

Front side: Back side:

9 modules have been built in Vienna:

8 Modules screwed together

beam

Arrangement on Telescope

• Stack of 8 DUT modules are mounted onto XYZ-stage of telescope by the help of a small adapter table:

DUTs

DUTs

• Since motorized stage allows also rotations of the DUT we will rotate one of the modules within the beam

Front End Hybrid with APV25

DAQ for the APV25 chip

• Frontend (FE) Hybrids are connected to Repeater Boards (REBO)• HV is coming from Keithley Source-meter via small board directly to FE (not shown)• Two 9U VME Boards with FADCs are reading data and digitalize them• NECO Board is the controller and distributes clock and trigger (via SVD3_Buffer board)• PC running CVI (LabWindows) is used for online monitoring and to store data

NECO board has LVDS I/O to directly read trigger and timestamp data from TLU box

(Thanks to David Cussins for providing a TLU box for testing this feature already weeks ago)

DAQ Hardware and Software

• DAQ Hard- and Software (including predecessors) has already been used for more than 10 testbeams in the past.

• Thus, everything is pretty stable.

Timing

• Trigger is distributed from TLU box to telescope and our setup

• Clock (40MHz) is generated locally by NECO• Latency can be adjusted by both NECO and APV

chips• APV25 chip has 50ns shaping time and analog

pipeline of 192 cells (corresponds to approx. 4us delay)

• Additional delays introduced by cables• DAQ online monitoring allows easy live

adjustment of timing

Data Analysis

Offline data analysis of DUT data:– Pedestal subtraction– Common mode correction– Hit finding, Clustering– Peak time reconstruction– Track Reconstruction (non existing)

We have three possibilities for tracking:– Use EUDET software as proposed by Ingrid

• Need to transfer our data into LCIO format

– Use SiLC (Prague group) analysis software written in ROOT• Transfer data from telescope and DUT to ROOT files

– Include tracking algorithms in Vienna Analysis code• Transfer data from telescope into proprietary ROOT files

} Existing software

Summary

• We will test the spatial resolution of a mini sensor with different geometric zones using the EUDET telescope as reference

• The testbeam starts next week (May 30th)• We feel well prepared for Data Taking

– Everything is ready and source tests have been performed on the lab test bench in Vienna (successfully)

– Will be transferred to CERN beginning of next week– TLU integration has already been successfully tested

• Offline Analysis: Vienna Analysis code works up to cluster finding and zero suppression

• Different options for Track Reconstruction– We have a diploma student in Vienna who will perform this

analysis