1. V.SavelievCBM Coordination Meeting1 Valeri Saveliev, Obninsk State University for Si-Strip STS Collaboration. CBM Coordination Meeting, Moscow, Russia, 5.11.2005 Si-Strip Tracker of CBM Experiment at GSI, Darmstadt

2. V.SavelievCBM Coordination Meeting2 Si-Strip STS Collaboration CKBM, St.Petersburg Si-STS design, construction aspects and technology Moscow Engineering and Physics Institute (University) Front end electronics and readout electronics Moscow State University, Si sensors design and technology, front end and readout electronics Obninsk State University, Si-STS system design, Monte Carlo simulation and analysis, Physics V.G.Khlopin Radium Institute, St.Petersburg, Si-STS design, Construction aspects, Radiation hardness test.

3. V.SavelievCBM Coordination Meeting3 Si-Strip STS Main features for Si-Strip STS in CBM Experiment  Extremely High Multiplicity,  Importance of Material Budget,  Requirement of High Resolutions. Schematic View of Geometry of the Si-Strip STS 4 Si-Strip Planes inside the Magnet (equivalent distances along z, starting 40 cm from Target )

4. V.SavelievCBM Coordination Meeting4 Monte Carlo Simulation and Analysis Monte Carlo Event simulation of Central Collisions of Au+Au 25 AGeV Obninsk State University Good experience in Monte Carlo and Analysis for High Energy Physics Experiments

5. V.SavelievCBM Coordination Meeting5 Occupancy of Si-Strip STS Total and Radial Occupancy of Si-Strip STS: STS_4, STS_5, STS_6, STS_7 (Si-Strip Sensors 100  m, no Mechanics Construction, no Support Structure) STS_4STS_5STS_6STS_7 Radial Occupancy of Si-Strip STS and problem of secondary particles limited of use the Si-Strip Thechnology in location close 40 cm from Target STS_4STS_5 STS_6STS_7

6. V.SavelievCBM Coordination Meeting6 Basic Technology of Si-Strip STS Double Sided Si-Strip Detectors Thickness : 100  m Pitch of strips : 25  m Stereo Angle: 15 o Sensors are 4’’, 300 µ thick, double-sided, 70 × 40.1 mm2, 110 µ/208µ readout pitch A set of strips are connected in serpentine; thus strips with following length: 28 cm, 56 cm, 112 cm and 224 cm are tested (SiILC Collaboration). Outer region of the Si-Strip STS: Long Lader Technology Inner region of Si-Strip STS: According the occupancy for STS_4: 4.2% for 2 cm length of strip

7. V.SavelievCBM Coordination Meeting7 Si strip STS_4 Layout Basic Elements: Inner : 6x2 cm Middle : 6x4 cm Outer :6X12 cm -20 cm +20 cm Read out

8. V.SavelievCBM Coordination Meeting8 Si strip STS_6 Layout Basic Elements: Inner : 6x4 cm Middle : 6x12 cm Outer :6X20 cm +40 cm -40 cm Read out +4cm - 4cm

9. V.SavelievCBM Coordination Meeting9 Experience in double side photolithography, first prototype for ATLAS SCT; Good new mask aligner for double side photolithography up to 6” Fine pitch (up to 25  m) sensors have been designed and produced for SVD-2 experiment at IHEP, Protvino; Radiation hard sensors designed, prototypes produced and tested up to 8 MRad for D0 RunIIb; Almost all equipment for Si-sensors testing. Si-Sensores Development Status Moscow State University 15 years experience in Si Sensors Design and Production; V.G.Khlopin Radium Institute, St.Petersburg Si-Detectors Design and Radiation Hardness Test

10. V.SavelievCBM Coordination Meeting10 Si-Sensores Development Status Test Station for Characterisation of Si-Strip Sensors Light protective box MKD light microscope Control and data acquisition electronic modules Software

11. V.SavelievCBM Coordination Meeting11 Si-Sensors R&D is necessary First of lall: Thickness of Si-Strip Sensors No well defined technology for 100  m thickness of Si-Strip Sensors up to now Long Lader Technology for Double Sided Si-Strip Sensors

12. V.SavelievCBM Coordination Meeting12 Si-Sensors R&D Double side polished silicon wafers: 300 µm – 25 wafers (for tests only) 200 µm – 50 wafers; (for prototype 150 µm – 50 wafers.production) Total Wafers Cost – 4000 ÷ 6000 Euro (Depends on Resistivity and Suplier) Photomasks design and production. For Double Side Sensors we need 14 or 15 photomasks. Cost about 500 - 600 Euro/mask Total Masks Production: 7000 ÷ 9000 Euro Sensor production cost (prototypes): 300 µm – 600 €/wafer; 200 µm – 700 €/wafer; 150 µm – 800 €/wafer. This is not a sensor cost !!! It might be a lot of sensors on wafer, total active area ~36 cm 2 Cost of Production of Prototypes(~50 wafers) 35 000 Euro

13. V.SavelievCBM Coordination Meeting13 Si-Sensores R&D Time Schedule Photomasks design and production - 3 months; Sensor prototype production: 300 µm – 10÷15 wafers - 4 months; 200 µm – first 10 wafers - 4 months; 200 µm – second 10 wafers – 2 months; 150 µm – first 10 wafers -3 months; 150 µm – second 10 wafers -2 months; In total according this optimistic schedule we will have about 50 wafers with different sensors in 12 – 14 months. Two last months mainly for testing sensors. Radiation tests could be started on the first batches of 10 sensors.

14. V.SavelievCBM Coordination Meeting14 Si-Strip STS Readout Si-Strip STS Readout is can’t be unified with other CBM Spectrometer System Readout The main aim of the ASIC to be developed for CBM Si-Strip detectors is to provide both amplitude and timing (event separation) measurements Mechanical (dimensional) fit (face-to-face) between strips and caseless ASICs Space limitation at the detector forces to provide reasonable multiplexing to save a number of cables (communication lines) to be used Data Driven Architecture (The Self-Triggering is an important issue) Accurate track reconstruction forces to have: – Massive parallelism of read-out – High complexity (functionality) of mixed-signal ASICs Radiation hardness (tolerance)

15. V.SavelievCBM Coordination Meeting15 PCs and Sun Workstations Linux and Solaris environment Cadence tools Europractice Design Kits ISE Si-Strip STS Readout Status Moscow Engineering and Physics Institute, Moscow State University Experience in the Readout Development for large scale Experiments in High Energy Physics MEPhI is Europractice full membership number A47530 Access to modern technology development

16. V.SavelievCBM Coordination Meeting16 Si-Strip STS Frontend Minimal signal – 7000 electrons per mip (100um detector thickness) Detector capacitance can be 30-300 pF depending on thickness and length of the strip, as follows from the simulation and design of tracker at a suitable signal/noise ratio Signal noise ratio – better than 10 for 1 mip Dynamic range (?) – 10 mips Input signals come at random time. Maximal average frequency of the signal at the chip input is 10 MHz Radiation hardness – 15-20 MRad Power consumption, as small as possible. The maximal one – few mW/channel Supply voltages depend on the technology Number of channels on the chip is dictated by tracker design (128, 256,….) Minimal number of external components.

17. V.SavelievCBM Coordination Meeting17 Si-Strip STS Technology Choice “Today 0.13-0.25 CMOS processes form the mainstream industrial production technologies and 0.13 um processes are coming on-line as the next industrial generation” (P. Jarron. Trends in microelectronics and nanoelectronics and their impact on HEP instrumentation. Proc. of the 8th Workshop on Electronics for LHC experiments, 9-13 Sept. 2002, Colmar, CERN/LHCC-2002-034, p.9-16) Probably it is expedient to add 0.25…0.35 µm Bi-CMOS processes. Bipolar is dictated by precise analog blocks (like low-offset comparators, erational amplifiers etc) Radiation tolerant Deep Sub Micron (DSM) 0.13 (0.25??)  m CMOS process (0.25 - 0.35  m Bi-CMOS one) for prototyping and studying the possibilities seems to be the best candidate and recommended last meeting at CERN Oct.24- 26

18. V.SavelievCBM Coordination Meeting18 Si-Strip STS Readout R&D Fabrication cost of prototype ASICs (given by e.g. Europractice) It strongly depends on the process. (Currently Europractice discounted prices are 240…7500 € /mm 2 type.)  ~100 channels/chip & ~1000chips/wafer  The mass (more correctly to say small volume) production cost should be comparable with prototyping cost. 1.5*10 6 channels  ~100 channels/chip & ~1000chips/wafer  ~15 wafers only! Designer man-power cost. It is roughly 2..4 man*year per each prototype ASIC Man power cost of test electronics development is about 1..2 man*year per each prototype ASIC On the way costs for computing (hard and soft) are estimated as a few k€/year Other costs include mechanical design (PCBs), assemblage and their tests

19. V.SavelievCBM Coordination Meeting19 Peak time adjustment Polarity Switch CSA Feedback adjustment Input protection Ccal Soft Limiter Limitation adjustment CR-RC(n) Shaper (n=2) Option 1 Scale amplifier To ADC Gain adjustment Switch array DAC array Test data Calibration (test) System T-Pulse Fast shaper Analog finder Threshold DAC

20. V.SavelievCBM Coordination Meeting20 ADC Buffer Pedestal Subtraction Pedestal memory Pedestal calculator Pedestal Measurement Mode Noise reduction Option 1 Shape reconstruction Signal finder Amplitude Time reconstruction Zero suppression Data reduction Interface (serial) Internal Pulser (phase control) External CLK Control

21. V.SavelievCBM Coordination Meeting21 Starting of the design on base preliminary Si-Strip STS Layout Actually technology is exists, but of course should be taking to account CBM specific items. Si-Strip STS Mechanics Structure CKBM, St.Petersburg Leader of high tech Carbon Composite Material Technology and Design of Mechanics Structures, well known in High Energy Physics: participating in the large scale projects of LHC

22. V.SavelievCBM Coordination Meeting22 Full Monte Carlo Analysis of Si-Strip STS in common simulation frame of CBM Experiment for optimisation of Design and Layout. Implementation of the Si-Strip STS in Physics Simulation Analysis. Study and Development of the technology for Double Sided Si-Strip Sensors with thickness of 100  m. Study and Analysis of Long Lader technology for outer part of the Si-Strip STS. Analysis and Development of the Structure of the Readout Chain of Si-Strip STS with emphasis of Data Driven Apchitecture. Design of specific Analog Front end part for the thin Si-Strip sensors, including the prototyping for the test setup of Si- Strip Sensors. Budget: R&D Si-Sensors and Readout ~150 kEuro for 2005 GSI visits ath the level of 24 man*months Summary Si-Strip STS R&D 2005