The Silicon Tracking System of the CBM Experiment
The Silicon Tracking System of the CBM Experiment at FAIR Evgeny Lavrik, for CBM Collaboration On behalf of the STS Workgroup 25. 10. 2018, ICPPA 18, Moscow
Outline of the presentation 1. Introduction 2. STS silicon sensors 3. Detector modules 3. System integration 4. COSY and m. CBM campaigns 5. Conclusions 2 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Future Facility for Antiproton and Ion Research (FAIR) FAIR is an international research facility located Darmstadt Ion beams from proton to uranium will be provided CBM is one of 4 major experimental pillars Expected start of operation 2024 A conceptual view of the future FAIR facility * cf talk of Paolo Giubellino earlier today 3 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Compressed Baryonic Matter (CBM) experiment 10 MHz interaction rate allows high statistics for rare and exotic probe detection Caveat: no hardware trigger on complex particle decays is possible Challenging solution: freestreaming read-out electronics with real-time software triggers Physics analysis is done on high performance computing farms The CBM experimental setup including, from left to right, Dipole Magnet, MVD, STS, RICH, MUCH, TRD, TOF, ECAL and PSD detector systems * cf talk of Viktor Klochkov today at 17: 25 4 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Silicon Tracking System (STS) Detector • Key detector to reconstruct particle tracks and resolve their momentum with Δp/p ≈ 1 -2% • Built out of ~900 silicon microstrip sensors forming 8 tracking stations • Fast electronics produce up to 40 k. W of thermal power in the close vicinity of the sensors • Very limited overall volume (~2 m 3) requires very efficient cooling View of the STS detector without thermal enclosure and services 5 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Silicon microstrip sensors State of the art microstrip technology Provide spatial hit resolution of about 25 μm Come in 4 different sizes, 2 manufacturers A photograph of prototype silicon sensors. 4 different sensor sizes are shown. Rich microscopic structure is prone to manufacturing errors and defects A feature rich corner region of the STS sensor 6 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Quality assurance of the sensors Detection of surface defects and electrical elements • Optical (all) and electrical (fraction) QA of the sensors is required • Optical: - allows to identify surface defects, such as scratches, strip and implant defects, control electrical element integrity, etc. - Based on a machine vision and machine learning algorithms for recognition • Electrical: - Allows to perform the global and per-strip measurements of a sensor, e. g. IV, CV dependencies, etc. - Employs a custom build probe station - Exhaustive QA procedures allow to identify pinholes, strip breaks and shorts, leaky strips, breakdown behavior, etc. 7 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Detector modules • Modules consist of a sensor, a bundle of microcables and ASICs placed on the Front-End-Board • Each sensor side is tab bonded to 8 micrcables, which in turn are bonded to 8 STS-XYTER ACICS Prototype detector module assembled in GSI • Module assembly workflow was developed and established • Assembly tools were designed, manufactured and supplied to the production sites (GSI, JINR) STS-XYTER chip developed in AGH, Krakow 8 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Detector modules (continued) • Modules consist of a sensor, a bundle of microcables and ASICs placed on the Front-End-Board • Each sensor side is tab bonded to 8 micrcables, which in turn are bonded to 8 STS-XYTER ACICS Front End Board PCB • Module assembly workflow was developed and established • Assembly tools were designed, manufactured and supplied to the production sites (GSI, JINR) 9 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR Microphotograph of the Alu-microcable before cutting Produced at LTU, Kharkov 25. 10. 2018
Sensor Ladders • The carbon fiber ladders will provide the means to arrange the sensors in units and stations • The sensors are mounted to the ladders with special fixtures – fiberglass L-Legs • The assembly fixtures were developed allowing for high mechanical placement precision Carbon fiber ladders 5 -Module ladder assembled 10 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Detector read-out chain • The prototype read-out chaing for silicon sensors with STS-XYTER chip was developed in GSI • Provides means for ADC calibration processes • Allows the noise estimation with real silicon sensors Detector read-out chain with a sensor connected to a STSXYTER chip on a FEB-B (top) and the FEB-B to data processing board with an uplink to the control PC 11 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
System Integration & Cooling • STS is a compact detector with high degree of component density • The conceptual engineering design is highly developed • Thermally insulated and air tight to prevent condensation • Use of evaporative bi-phase CO 2 cooling due to space constraints • Direct sensor cooling by dry gas flow • Mock-ups and demonstrators being prepared • Alignment of sensors is important * cf talk of Susovan Das later this session 12 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Detector performance • Detector performance is investigated w. r. t. many metrics - Material budget - Track reconstruction efficiencly - Momentum resolution - Hit residuals - Primary vertex reconstruction - Noise performance - and many more. . * cf my poster from Monday online 13 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Key project institutes GSI-FAIR, Darmstadt, Germany; JINR, Dubna, Russia; Univ. Tübingen, Germany; KIT, Karlsruhe, Germany; AGH, Cracow, Poland; JU, Cracow, Poland; WUT, Warsaw, Poland. Assembly Centers: GSI-FAIR, JINR –VBLHEP, KIT Project Timeline: 2013 – Technical Design Report 2017 -2018 – Production Readiness (Sensors, Electronics, System Integration) - Detector construction until 2022 - Commissioning until 2023 - 14 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
FAIR Phase 0: m. CBM@SIS 18 campaign • m. CBM is a piloting project employing the mini-versions of all detector systems of CBM experiment, joint effort of all groups involved • m. STS will consist of 2 stations - (4 units) • Hence minimalistic design, all components from the final version of the STS detector will be used Integration concept of m. STS by O. Vasylyev 15 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
FAIR Phase 0: BM@N (Baryonic Matter at Nuclotron) ~5 k. Hz interaction rate - up to 50 k. Hz (> 2021) The BM@N experimental setup with detector systems Beams of light and later (with booster) heavy ions with energies in range 2 to 6 A Ge. V p+p and p+A reactions studied for the reference 6 layers of GEM & 3 layers of Si ⇒ later upgraded to 7 GEM / 4 Si Triggered read-out BM@N STS sensor layout 16 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
Conclusions and outlook • The sensor development is concluded with tendering • High readiness for quality checks • Module and ladder assembly procedures are improved beyond prototyping stage • Mechanical design and integration concepts are on very high level of detalisation • Cooling concepts for sensors and electronics are alborated and will be tried out with demostrators • FAIR Phase 0 projects are advancing and aiding the STS development 17 | E. Lavrik. The Silicon Tracking System of the CBM Experiment at FAIR 25. 10. 2018
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