The NA61 Vertex Detector – electronics and readoutStarting the prototype phase

M. Deveaux, Goethe University Frankfurt

What is the topic ?

M. Deveaux, NA-61 Collaboration Meeting, October 2013 2

The properties of the MIMOSA-26 sensors (reminder)Operating MIMOSA-26 in an 2015 heavy ion run with NA61?

• Challenges ahead• Status at CBM – IKF

3

CMOS-MAPS, the fundamentals

Monolithic Active Pixel Sensors(MAPS, also CMOS-Sensors)

• Invented by industry (digital camera)

• Modified for charged particle detection by the PICSEL group, IPHC Strasbourg

Selected communities participating in MAPS R&D

CBM MVD

ALICE ITS

STAR HFT

EU-DET

TESLA ILC Vertex .

2000 2005 2010

AIDA

4M. Deveaux

MIMOSA-26: The operation principle

Reset+3.3V+3.3V

Output

SiO2 SiO2 SiO2

N++ N++N+ P+

P-

P+

15µm50µm

Pixel readout concept

5

External ADCSensor Offline Cluster

finding

Output

Add pedestal correction

~1000 discriminators

On - chip cluster-finding processor

Output: Cluster information(zero surpressed)

MAPS are built in CMOStechnology

Allows to integrate:• sensor• analog circuits• digital circuits

on one chip.

Block diagram of MIMOSA-26

M. Deveaux, NA-61 Collaboration Meeting, October 2013 6

8 x analog out (obsolet)

Readoutsequencer

Slow controlinterface (JTAG)

Bias DACs (Threshold generation…)

Coll. discri-minators

Zero suppr.computer

Outputmemory

Sensor array (21200 x 10600 µm²)

18.4 x 18.4 µm pixel pitch

The NA-61 MVD, a spin-off of the CBM-MVD project?

M. Deveaux, NA-61 Collaboration Meeting, October 2013 7

The CBM-MVD prototype:

Based on 12 MIMOSA-26

Results from SPS-beam test:• MIP efficiency: > 99

%• Spatial resolution: ~ 4

µm

Vacuum compatible cooling support (CVD diamond)

Material budget: <0.3% X0 (incl. two silicon layers and support)

• The CBM-MVD prototype is not meant for physics but it has about the complexity of the NA61 prototype

• NA61 may start its activity supported by existing know how and tested hardware components

The idea: An MVD prototype which might see open charm

M. Deveaux, NA-61 Collaboration Meeting, October 2013 8

[W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745]

SIS18

SIS100SIS300

SPS

CBM ~ 10-4 D/coll.

NA-61~ 0.1 D/coll.

CBM - >> 50 kHz (heavy ion, minimum bias, untriggered)NA61 - 80 Hz (out of 2 kHz minimum bias, triggered)Þ A measurement within 2015 HI-run might see open charm Þ But: Needs a complex detector system

What do we have: Ladders from ALICE ITS

M. Deveaux 9

What do we have?

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Mechanical support and cooling:Responsible: Grigory Feofilov (St. Petersburg)

Sensors:Purchase: M. Winter et al. (IPHC Strasbourg)

Flex print cable:M. Deveaux / J. Stroth et al. (CBM, Goethe University Frankfurt)

Analog boards:Might be purchased from J. Stroth et al. (CBM, Goethe University Frankfurt)

What do we have?

11

TRB3 FPGA BoardPurchase: M. Traxler, GSI

NA61 DAQ A black box…… but it does certainly exist

Electronics hardware components mostly available and tested

What is missing?

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Mechanical support and cooling:• Target vessel: Design, construction, feed throughs• Movement engine: Move MVD out during beam tuning=> Pawel, Krakow

Sensors:• Probe test (OK – Deveaux et al., IKF)• Gluing (OK – Deveaux et al., IKF)• Bonding (OK – Deveaux et al., IKF)• Transport and handling tools

Slow control software:• JTAG interface: Purchase from J. Stroth?• Adaptation to NA-61 standard• Interface to NA-61 data base

Analog boards:• SEU recovery system (Software)• Test SEU recovery system

What do we need?

13

TRB3 FPGA Board• Sensor control software • Data reduction (remove idle bits)• SEU recovery• Sync control• Time stampingMight be purchased from CBM or developed in synergy.

NA61 DAQ

Sizable work for assembling and software/firmware is needed

TRB3 – NA61 interface• Data format• Trigger handling• Data selection / synchronization• System tests

Data analysis with NA61 software• Unpacker• GEANT simulation tools• MVD – tracking• Alignment• Open Charm analysis tools=> Pawel, Krakow

Data QA and safety• Real time monitors• Temperature control• LV control• Beam abort system

The MIMOSA-26 NA61 Interface

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Sensor

discrimi-nators

cluster-finder

Readout pointer

• MIMOSA-26 has a rolling shutter readout

• Once particles arrive, the readout pointer has to pass by to record them

Frame N

• The hits below the pointer will be recorded in a data set labeled Frame N

The MIMOSA-26 NA61 Interface

M. Deveaux, NA-61 Collaboration Meeting, October 2013 15

Sensor

discrimi-nators

cluster-finder

Readout pointer

• MIMOSA-26 has a rolling shutter readout

• Once particles arrive, the readout pointer has to pass by to record them

Frame NFrame N+1

• The hits below the pointer will be recorded in a data set labeled Frame N

• The hits above will be recorded later and end up in Frame N+1

• Online sorting is needed to connect the hits to their trigger

A word on data rates

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160 Mbps

2 Gbps

5.8Gbps NA61 DAQ

~ 1

Gbp

s

According to Marek: 1 Gbps not ok=> Needs data reduction on TRB-3=> Need to implement trigger in FPGA

Preparation of test and integration of the sensors

17

Gray room / Clean room being completed at IKF

Bondingmachine

Siliconstorage(dry nitrogen)

M. Deveaux, NA-61 Collaboration Meeting, October 2013

Semi automatic probe testing machine

18

Optical andEM- shielding

M. Deveaux, NA-61 Collaboration Meeting, October 2013

Probe card for MIMOSA-26

19

First probe cards delivered

• Establish procedure (CBM - project)

• Do first tests with B-grade sensors (CBM - project)

• Perform real tests (NA-61 Project)

M. Deveaux, NA-61 Collaboration Meeting, October 2013

Latch-up – a radiation induced, reversible short circuit

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Latch-up may occure if particles hit sensitive structures like CMOS-Inverters.

The structures of the inverter act as parasitic thyristor, which is switched on=> Short circuit in the device

Latch-up – a radiation induced, reversible short circuit

M. Deveaux, NA-61 Collaboration Meeting, October 2013 21

IC affected by latch - up

If no action is undertaken, the device is destroyed by over-current (thermal overload).

Detecting the over current and performing power cycling solves the problem (thyristor is switched off).

Latch-up

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Sensor

Computer

Sensors must be protected against latch-up

„May 2009 Latch up tests - report ”Michal Szelezniak, Leo Greiner

Not Mimosa-26

Mi26- sensors

Mi26- computer

Latch-up protection

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Power supply with improved latch-up protection is under construction

Part of a bigger electronics upgrade

Upgrade of the readout board

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Summary and conclusion

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• An MVD based on MIMOSA-26 is suited for NA61• The technology was tested with the CBM-MVD prototype• Most hardware components for an NA61 MVD are available

• Building an NA61 prototype will require manpower foro Assemblingo Testingo Adapting software and hardware to NA61

• The IKF Frankfurt has commited for probe testing, gluing and bonding the sensors.

• The activity may be started as soon as funding is available• Additional hardware might be of interest, needs discussion

The CBM prototype needed 3 years of preparation with ~ 10 peopleNA61 goal: <1.5 years until measuring open charm

Þ Project requires support from NA61 specialistsÞ Helping hands are welcome