„Prototyping the CBM Micro Vertex Detector” Group report Michal Koziel Goethe-Univiersität, Frankfurt for the CBM-MVD collaboration 1

Outline 2  CBM experiment and its requirements  Sensor development towards the CBM Micro Vertex Detector  Prototyping the CBM-MVD  Mechanical integration  Readout electronics and DAQ  Data analysis  Outline & summary

Required performances (SIS-100) Radiation tolerance > n eq /cm 2 & >1 Mrad Read-out speed> 30 kframes/s Intrinsic resolution< 5 µm Operation in vacuum „Light” support and cooling Material budget ~ 0.3 % X 0 CBM-MVD will: -improve secondary vertex resolution -background rejection in di-electron measurements -host highly granular silicon pixel sensors featuring fast read-out, excellent spatial resolution and robustness to radiation environment. 3 The MVD – required performances MVD

Sensor R&D DAQ Mechanical integration Sensor R&D System integration Prototype highlights: Develop sensor readout system capable to handle high data rates Provide cooling and support with low material budget employing advances materials Research fields towards the MVD 4 Data analysis

5 Sensor R&D

Technology of choice: MAPS 6

Progress in CMOS sensor development 7 CBM SIS100 MAPS (2003) MAPS (2010) MAPS (2012+) Spatial resolution ~ 5 µm1.5 µm4 µmpreserved Material budget [X 0 ] < 0.3%~ 0.1%~ 0.05%preserved Non-ionizing radiation tolerance [n eq /cm²] > >10 13 preserved Ionizing radiation tolerance [Mrad] > 10.2> 0.5> 1 Readout time / frame < 30 µs~ 1 ms110 µs Sub-arrays with rolling shutter r.o. Standard EPI 0.35 μm CMOS HR EPI 0.35 μm CMOS HR EPI 0.18 μm CMOS

Non-ionizing radiation tolerance 8 Shown: DPG Mainz 2012 HK 12.8 To be published in NIM A High resistivity epitaxial layer increases radiation hardness by one order of magnitude Low resistivity EPI 10 Ω∙cm High resistivity EPI 1 kΩ∙cm

Ionizing tolerance 9 Presentation: HK 9.5: Montag, 4. März 2013, 12:15–12:30, HSZ-405 This session Covered by Dennis Doering: the same session !

10 Mechanical integration Poster: HK 52.14: Mittwoch, 6. März 2013, HSZ 2.OG

Material budget: ~ 2.45 % X 0 Sensor: MIMOSA-20 ~200 frames/s few n eq /cm 2 & ~300 kRad 750µm thick Cooling & support: TPG+RVC foam Material budget: ~ 0.3 % X 0 Sensor: MIMOSA-26 AHR ~10 kframes/s ~10 13 n eq /cm 2 & >300 kRad 50µm thin Readout CP/digital/high data rates Cooling & support: pCVD diamond (thermal grade) Readout Serial/analog...will meet all requirements Sensor: synergy with ALICE (diff. geometry) Readout speed: ~30 kframes/s Radiation tol.: >10 13 n eq /cm 2 & >1 Mrad Demonstrator Prototype Final ½ (!) of 1 st station 4 sensors 2012 >2015 Progress towards the MVD Sensor 50 µm Al heat sink CVD diamond Flex Cable 200 µm FEB Encapsulation Wire bonds Glue 200 µm

Main features: -in pixel amplification -binary charge encoding - discriminator for each column - 0-suppression logic -pitch: 18.4 μm - ∼ 0.7 million pixels MIMOSA-26 AHR: 0.35µm process, High Resistivity (HR) EPI (1 kΩ·cm) 21.2 x 10.6 mm 2 Sensors for the MVD prototype 12

Positioning Aspects addressed during prototyping phase Sensor Carrier Glue FPC Sensor integration on CVD diamond: Readout & control Scalability Reliability Adhesive bonding Wire bonding Encapsulation FPC Double sided sensor integration Micro-tracking Beam T1 T2 T3 T4 DUT micro-tracking r/o Plane 2 Plane 1 Plane 4 Plane 3 DUT Cooling Front scintillator Back scintillator Cooling optimization

14 Test beam setup at T1 T2 T3 T4 DUT Beam Material budget: % X 0 Material budget: % X μm CVD diamond 1 mm Al 200 μm CVD diamond

15 DAQ Poster: HK 52.1: Mittwoch, 6. März 2013, HSZ 2.OG

16 FPC based on MIMOSA-26 FEB... clock start reset JTAG converter board converter board converter board... readout controller board driver board FEB sensors... readout controller board FEB LVDS, 1m 4x 80 Mbit/s (MIMOSA-26) LVDS 4 x 80 Mbit/s FPC 2 Gbit/s optical fiber to the MVD network FPC Slow control board Dedicated DAQ Hub readout controller board readout controller board PC General purpose add-on HADES TRB V2 ~30 m

Tests before beam time 17  Stability runs  Slow control cross-check  Tests with radioactive sources  Threshold scans  Cooling check  Test with long cables ... Fully operational setup ready for travelling to CERN Laboratory setup

18 Full beam setup at SPS Huber cooling system DAQ Beam telescope FEE

DAQ performance during beam tests 19 The Readout Network was proven to be highly scalable. All sensors are synchronized: No deviations detected within 10 ns precision. DAQ runs very stable: No network errors, no data loss (5 days of tests) Data rates: 6 MB/s - 25 MB/s but also overload test with +100 MB/s. JTAG passed also all tests ( programming cycles per chain). In total 2TB of data stored 12 sensors running in parallel Frame number 110 ms ~8 s CERN-SPS Spill structure 40 s8 s

20 Data analysis Poster: HK 52.13: Mittwoch, 6. März 2013, HSZ 2.OG

1 -> 18.4 μm Data analysis 21 Data analysis flow: 1.Cluster analysis 2.3D alignment 3.Track selection with the 4-plane telescope (straight lines) 4.Response of DUT to charged particles 20 – 120 GeV Pions CERN SPS North Hall Plane 1 Plane 2 Beam setup beam Plane 3Plane 4 DUT [Pixel pitch]  =5.5 μm Detection efficiency, Fake Hit Rate, Spatial resolution as a function of threshold voltage (DUT) 4 inclination angles of 0 ,30 ,45 , 60  Temperature (-6, +6, +17  C) & threshold scans High beam intensity runs (in average up to 10 hits/frame but due to the non-uniform beam it could also be ~100 hits / some of frames – to be confirmed)

22 Cluster shape studies Top 8 most frequently observed cluster shapes Cluster classification will be used for further FPGA-based data compression Center of gravity used to compute the “hit” position

Cluster multiplicity studies 23

Detection Efficiency (DUT) 24 probe V threshold Amplitude time NOISE = individual pixel feature signal noise „safe” region Example: FHR < Efficiency > 95%

Spatial Resolution (DUT) Result for the DUT: σ x = 3.3 µm 25 Spatial resolution: DUT only X (row) back sensor Al heat sink FEB 200 µm Front sensor Back sensor π-π- Correlation back - front X (row) front sensor Reproducing the intrinsic parameters of the sensors validates the concept of the prototype.

Outlook & summary p Mechanical integration Sensor R&D Achieved:  An ultra low material budget (0.3% X0) double-sided micro-tracking device: 2x2 sensors, CVD Diamond, glue & FPC.  Development of tools & assembly procedures. Towards the CBM-MVD:  Vacuum compatibility and integration into the CBM-MVD vacuum box  design the MVD platform in the target vacuum chamber  cable routing  finalize services (LV, cooling)  Improve in heat transfer.  Quality assurance while assembling (yields) Achieved:  Radiation tolerance of CMOS sensors meets the requirements of the CBM experiment concerning SIS-100 scenario. Towards the CBM-MVD:  Readout time needs further improvements.

Outlook & summary p DAQ Data analysis Achieved:  Synchronization  Reliability  Scalability  Slow control & monitoring tools  Data quality Towards the CBM-MVD:  Interface to the CBM DAQ  Optical data link between FEE and DAQ board Achieved:  package for alignment and data analysis for test beam setup (telescope-DUT)  online monitoring software (test beam setup) Towards the CBM-MVD:  Optimizing the digitizer based on data on sensor response  Performance studies of physics cases allowing for more realistic studies on detector performance The successful test beam time validates the integration and readout concept, and concludes the prototype phase of the CBM-MVD plane 1&2

28 Thank you for your attemtion ! Thank you for your attention...

BACKUP 29

Setup: Telescope & DUT StationCarrierSensorT (°C)x/X 0 (%) T1 200  m CVD Diamond frame*)50  m M26-AHR T2 200  m CVD Diamond frame*)50  m M26-AHR DUT 200  m CVD DiamondTwo 50  m M26-AHR, double-sided -6.5, 6, 170.3**) T31 mm thick Al frame*) 50  m M26-AHR T41 mm thick Al frame*) 50  m M26-AHR Beam Scint. 1 Scint. 2 T1 T2 DUTT3T4 *) no material in active area, cut-out **) conservative estimation of glue thickness Note: Beam: 20, 60, 120 GeV/c pions Telescope: 2 setups used, compact (shown) and stretched (s. front page). 30 Detector stations at the beam setup

How to integrate all those things ? 31 CVD Al

Tools 32 ZOOM

Bond encapsulation Soft, silicon-based elastometer Sylgard 186 Used at CMS experiment at LHC. Yield after encapsulation = 100 % (16 sensors) 33 Wire bond encapsulation

Which glue ? Best: -High thermal conductivity -Easy to rework -Radiation tolerant -Strong -With low material budget -Low outgassing …a pity that such an adhesive does not exist.. Thor Labs S-10 Epotecny E505 Epotecny E501 High viscosityMedium viscosity Low viscosity Selected for prototype phase Sensor integration: Michal Koziel =>

Underfilling Sensor (Si USA dummy -> Mimosa-26)  m separator (glue dot without metal filler) Support (glass -> CVD diamond) “L-shape” adhesive Thermal management Reworkability Material budget ? Pros & cons:

Underfilling – problems to address sensor adhesive support Bonding is impossible Minimum sensor to support distance allowing glue dispersion Problem 1 Problem 2 glue thickness material budget

Channeling Sensor (Si USA dummy -> Mimosa-26) Adhesive without metal filler Support (glass -> CVD diamond) Thermal management Reworkability Pros & cons: