The NA61 Vertex Detector – electronics and readout Starting the prototype phase

1. The NA61 Vertex Detector – electronics and readout Starting the prototype phase M. Deveaux, Goethe University Frankfurt

2. What is the topic ? • 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 M. Deveaux, NA-61 Collaboration Meeting, October 2013

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 TESLA ILC Vertex . STAR HFT CBM MVD AIDA • EU-DET ALICE ITS 2005 2000 2010

4. MIMOSA-26: The operation principle +3.3V Reset +3.3V Output SiO2 SiO2 SiO2 N++ N++ P+ N+ P- 50µm 15µm P+ M. Deveaux

5. Pixel readout concept Offline Cluster finding Sensor External ADC Output Add pedestalcorrection • MAPS are built in CMOS • technology • Allows to integrate: • sensor • analog circuits • digital circuits • on one chip. ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zerosurpressed)

6. Block diagram of MIMOSA-26 8 x analog out (obsolet) 18.4 x 18.4 µm pixel pitch Readout sequencer Sensor array (21200 x 10600 µm²) Coll. discri- minators Bias DACs (Threshold generation…) Slow control interface (JTAG) Zero suppr. computer Output memory M. Deveaux, NA-61 Collaboration Meeting, October 2013

7. The NA-61 MVD, a spin-off of the CBM-MVD project? The CBM-MVD prototype: Based on 12 MIMOSA-26 Vacuum compatible cooling support (CVD diamond) Material budget: <0.3% X0 (incl. two silicon layers and support) • Results from SPS-beam test: • MIP efficiency: > 99 % • Spatial resolution: ~ 4 µm • 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 M. Deveaux, NA-61 Collaboration Meeting, October 2013

8. [W. Cassing, E. Bratkovskaya, A. Sibirtsev, Nucl. Phys. A 691 (2001) 745] SPS SIS100 SIS300 SIS18 The idea: An MVD prototype which might see open charm NA-61~ 0.1 D/coll. CBM ~ 10-4 D/coll. • CBM - >> 50 kHz (heavy ion, minimum bias, untriggered) • NA61- 80 Hz (out of 2 kHz minimum bias, triggered) • A measurement within 2015 HI-run might see open charm • But: Needs a complex detector system M. Deveaux, NA-61 Collaboration Meeting, October 2013

9. What do we have: Ladders from ALICE ITS M. Deveaux

10. What do we have? 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) M. Deveaux, NA-61 Collaboration Meeting, October 2013

11. What do we have? TRB3 FPGA Board Purchase: M. Traxler, GSI NA61 DAQ A black box… … but it does certainly exist Electronics hardware components mostly available and tested

12. What is missing? • 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 M. Deveaux, NA-61 Collaboration Meeting, October 2013

13. What do we need? • TRB3 FPGA Board • Sensor control software • Data reduction (remove idle bits) • SEU recovery • Sync control • Time stamping • Might be purchased from CBM or • developed in synergy. • Data QA and safety • Real time monitors • Temperature control • LV control • Beam abort system • TRB3 – NA61 interface • Data format • Trigger handling • Data selection / synchronization • System tests NA61 DAQ • Data analysis with NA61 software • Unpacker • GEANT simulation tools • MVD – tracking • Alignment • Open Charm analysis tools • => Pawel, Krakow Sizable work for assembling and software/firmware is needed

14. The MIMOSA-26  NA61 Interface • MIMOSA-26 has a rolling shutter readout • Once particles arrive, the readout pointer has to pass by to record them Sensor Readout pointer • The hits below the pointer will be recorded in a data set labeled Frame N discrimi-nators cluster-finder Frame N M. Deveaux, NA-61 Collaboration Meeting, October 2013

15. The MIMOSA-26  NA61 Interface • MIMOSA-26 has a rolling shutter readout • Once particles arrive, the readout pointer has to pass by to record them Sensor Readout pointer • The hits below the pointer will be recorded in a data set labeled Frame N discrimi-nators • The hits above will be recorded later and end up in Frame N+1 cluster-finder • Online sorting is needed to connect the hits to their trigger Frame N+1 Frame N M. Deveaux, NA-61 Collaboration Meeting, October 2013

16. A word on data rates NA61 DAQ 5.8Gbps 160 Mbps ~ 1 Gbps 2 Gbps According to Marek: 1 Gbps not ok => Needs data reduction on TRB-3 => Need to implement trigger in FPGA M. Deveaux, NA-61 Collaboration Meeting, October 2013

17. Preparation of test and integration of the sensors Gray room / Clean room being completed at IKF Silicon storage (dry nitrogen) Bonding machine M. Deveaux, NA-61 Collaboration Meeting, October 2013

18. Semi automatic probe testing machine Optical and EM- shielding M. Deveaux, NA-61 Collaboration Meeting, October 2013

19. Probe card for MIMOSA-26 • 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

20. Latch-up – a radiation induced, reversible short circuit 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 M. Deveaux, NA-61 Collaboration Meeting, October 2013

21. Latch-up – a radiation induced, reversible short circuit If no action is undertaken, the device is destroyed by over-current (thermal overload). IC affected by latch - up Detecting the over current and performing power cycling solves the problem (thyristor is switched off). M. Deveaux, NA-61 Collaboration Meeting, October 2013

22. Latch-up Mi26- computer Computer Mi26- sensors Not Mimosa-26 Sensor „May 2009 Latch up tests - report ” Michal Szelezniak, Leo Greiner Sensors must be protected against latch-up M. Deveaux, NA-61 Collaboration Meeting, October 2013

23. Latch-up protection Power supply with improved latch-up protection is under construction Part of a bigger electronics upgrade M. Deveaux, NA-61 Collaboration Meeting, October 2013

24. Upgrade of the readout board M. Deveaux, NA-61 Collaboration Meeting, October 2013

25. Summary and conclusion • 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 for • Assembling • Testing • 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 people • NA61 goal: <1.5 years until measuring open charm • Project requires support from NA61 specialists • Helping hands are welcome M. Deveaux, NA-61 Collaboration Meeting, October 2013