Test of the MAPS add-on board

S. Amar-Youcef, M. Deveaux, D. Doering, C. Müntz, S. Seddiki, P. Scharrer, Ch. Schrader, J. Stroth, T. Tischler

Outline

• Test setup– Mi 20 – Sensor

• Data analysis• Results: Test MAPS add-on board• Summary

CBM Collaboration meeting Split 2009 2 / 16

Test setupTest setupOnly acquisition board changed in contrast to reference systemOnly acquisition board changed in contrast to reference system

Mimosa20 (2008)

Auxiliary board, power supply, signal processing, data transfer

HADES-DAQ compatible, no dead time, big RAM space for data storage or buffering, 50MHz readout clock;Data processing:digitalization, sparsification

Analysis

Sensor

Frontend board (PCB)

MAPS add-on boardon TRB2 (TRBnet)

PC

Data transfer:I/O card or OP-link

Monitoring

Analog signals Sync. signals

CBM Collaboration meeting Split 2009 3 / 16

Mimosa 20 - SensorMimosa20 (2008):Mimosa20 (2008):

•Differential analog output •2 banks•10 submatrices•Multiplexed onto 2 outputs•50 MHz •200 kPixels•30 µm pixel-pitch•SB pixels

30 µm

Cparasitic

Recharge diode

Collecting diode

Output

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Properties SB-pixel

Cparasitic

Recharge diode

Collecting diode

OutputIrecharge

Ileakage

Potential at output:

Equilibrium: Irecharge =Ileakage

CDS (Correlated Double Sampling):

Noise

CBM Collaboration meeting Split 2009

Potentiometer

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Chip slow controlChip slow control

• JTAG interface for chip settings•Working point of source follower•Level marker pixels•Level of signals•Amplification•Analog buffer•Differential output buffer

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Clusterfinding

Noise

Hit-signal(Pixels over threshold)

Data analysis softwareData analysis softwareData taken and stored!

Import

CDS

Demultiplexing

DataDataData

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Noise in one Pixel

Noise [ADC]

Charge spectrum of 55-Fe source

Key observables:Key observables:

Noise [ADC]

Calibration [e-/ADC]

GainKα (55Fe )

Noise [e-]

CBM Collaboration meeting Split 2009

Noise Histogramm

Pixel to pixel dispersion of Noise

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Status on last collaboration meetingStatus on last collaboration meeting

• We could start running this setup for a first time– Readoutchain working properly– But performance of analoge electronics not clarified

Goal: Goal: •Validate the board designValidate the board design•Check whether we can reach aspired performance Check whether we can reach aspired performance •Maximize sensitivity ↔ minimize noise Maximize sensitivity ↔ minimize noise •Understand MAPS add-on board in detailUnderstand MAPS add-on board in detail

Approach: Approach: •Systematic measurementsSystematic measurements•Optimize settingsOptimize settings

CBM Collaboration meeting Split 2009 9 / 16

ResultsResultsCalibration: gain (@ f=50MHz)

Each data point measured with ‚optimal‘ settings!

Discharge of Kα signal, due to higher recharge current at higher temperatures!

CBM Collaboration meeting Split 2009 10 / 16

SB-Pixel:SB-Pixel:

Potential at output with hit:

Irecharge > Ileakage

Irecharge = Ileakage

Irecharge < Ileakage + ISignal

CDS:

Hit-signal

At higher leakage current:Pixel recharge faster Hit signal smaller

CBM Collaboration meeting Split 2009 11 / 16

Calibration: gain (@ f=50MHz)

Expected saturation value:Expected saturation value:408 ADC = 1640 e408 ADC = 1640 e-

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Noise w.r.t. chip temperature:

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Noise w.r.t. readout frequency:

Conclusion: properties are comparable to reference system The MAPS add-on board is working well!

CBM Collaboration meeting Split 2009 14 / 16

Status nowStatus now

• Full control of the chip– Understand the behaviour by tuning the different

parameters– Know how to balance the parameter against each other in

order to optimize the noise

• Results match the design goals

CBM Collaboration meeting Split 2009 15 / 16

Summary

• MAPS add-on board – Working well– Understand how to control the Mi20 with– Ready for beamtime

• Further steps:– Prepare setup and software for upcoming

beamtime

Thank you!CBM Collaboration meeting Split 2009 16 / 16

Backup slides

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IN P U T-V oltage[m V ]

deflection

m esured value 100kH z

m easured value 1M H z

m easured value 10M H z

m easured value 30M H z

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CBM Collaboration meeting Split 2009

U-I – characteristics of diode:

Non-linear behaviour

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