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Bochum, 17.3.2009 Marius C. Mertens

Application of a

Versatile Digital Readout System

for the PANDA Micro Vertex Detector

James Ritman, Tobias Stockmanns

HK 30.5

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Outline

Introduction

The PANDA MVD in a Nutshell

Silicon Pixel Detector Characterization

Experimental Setup

Digital Readout System

Readout of the Atlas FE-I3

Verification of Base Functionality

Pixel Characterization

Threshold Tuning

TOT Response

Connection to the PANDA ToPiX Prototype

Summary

PANDA and the MVD

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Antiproton – Proton

fixed target experiment in the

charm mass energy regionDetails:

Group Report HK 40.1, T. Stockmanns

Antiproton Beam

Target

Silicon Pixel Detector Characterization

Microvertex detector: Silicon pixel and strip sensors

Pixel detector frontend electronics

FE-I3 used in Atlas detector

ToPiX custom electronics under development

Individual TOT measurement circuit per single pixel cell

Accuracy improvement (charge sharing), dE measurement

Characteristic parameters: Threshold, noise

Operation parameters controlled by on-chip registers

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Details on ToPiX:

HK 40.2, D. Calvo

Charge

Time

Threshold

Silicon Pixel Detector Characterization

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ChargeThreshold

Hit %

Hit detection by discriminator Ideal pixel response

Reality:

Noise charge + Signal charge

Noise: Gaussian distribution

Pixel response: Error function

(Convolution of Gaussian + Heaviside)

Charge deposition > Threshold

Injected Charge (a.u.)

En

trie

s

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Experimental Setup: Digital Readout System

Philips HD 7810/60 Senseo II

Optical Link to PC SiS1100 Digital Readout Board Atlas FE-I3

Adapter Board

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Verification of Base Functionality

FE-I3 test panel and results

Atlas FE-I3 register test:Comparison: Known data Returned data

Shift register + latches

1. Transmission of known data (shift register)

2. Configuration of latches

3. Shift register flush

4. Readback of latches (to shift register)

5. Readback of shift register

6. Data comparison

green light test passed

red light test failed

Silicon Pixel Detector Characterization

Noise σ and Threshold μ

Characteristics determination Threshold scan

Repeated injection of a set of known charges

Record response % as function of injected charge

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Threshold: 324

Noise: 8.8

En

trie

s

Injected Charge (a.u.)

Threshold Distribution (Untuned FE-I3)

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Mean: 179,5

Sigma: 43,1

En

trie

s

Threshold (a.u.)

Pixel Column Index

Pix

el R

ow

Ind

ex

Th

resh

old

(a.u

.)

Threshold Tuning (Quick Tune)

Threshold tuning via per-pixel TDAC setting

Intervall halving method

One Iteration per TDAC bit

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0

200

400

600

800

1000

1200

0 20 40 60 80 100 120 140

Target Threshold

Th

resh

old

(a.u

.)

TDAC Setting

Threshold Distribution (After Quick Tune)

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En

trie

s

Threshold (a.u.)

Pixel Column Index

Pix

el R

ow

Ind

ex

Th

resh

old

(a.u

.)

Mean: 199,6

Sigma: 3,9

Quick Tune Limitations Fine Tune

Quick tune: Pixel must be out of noise at first tuning step

Fine tune: Analyzes slope within window

needs more measuring points

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0

200

400

600

800

1000

1200

0 20 40 60 80 100 120 140

Target Threshold

TDAC Setting

Th

resh

old

(a.u

.)

Threshold Distribution (After Fine Tune)

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En

trie

s

Threshold (a.u.)

Pixel Column Index

Pix

el R

ow

Ind

ex

Th

resh

old

(a.u

.)

Mean: 200,1

Sigma: 1,2

Compare: Initial Threshold Distribution

Mean: 179,5

Sigma: 43,1

TOT Response

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Mean: 0,052

Sigma: 0,003

Slope distribution of

TOT Charge

response functions

(full chip)

TOT Data for injected charges

(single pixel)

TO

T V

alu

e

Injected Charge (a.u.)

En

trie

s

Slope

Connection to the ToPiX Prototype

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ToPiX FE

mounted on DUT support

Adapter Board

Summary

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Details on the digital

readout system:

HK 67.98

Silicon pixel detector characterization: Threshold & noise

Measurements with the digital readout system

Verification of frontend chip‘s base functionality

Individual pixel‘s response to charge injection

Theshold distribution of on-chip pixels

Threshold tuning to target value

TOT Response to charge injection

Connection to the PANDA ToPiX Prototype