1 J.M. Heuser − Status of the Silicon Tracking System Johann M. Heuser CBM Collaboration Meeting GSI, 15 April 2010 Status of the CBM Silicon Tracking System

2 J.M. Heuser − Status of the Silicon Tracking System 13 contributions from STS team covering simulations, beam test, detector tests, radiation hardness, demonstrator module, ladder + station engineering, FEE

3 J.M. Heuser − Status of the Silicon Tracking System STS Workgroup

4 J.M. Heuser − Status of the Silicon Tracking System

5 STS stations area, 8 stations: 3.2 m 2 number of sensors: sensors, 2 cm × 6 cm 166 sensors, 4 cm × 6 cm 714 sensors, 6 cm × 6 cm number of sectors: 756 number of r/o channels: 1.5  10 6 number of FE chips: 1.2  10 4

6 J.M. Heuser − Status of the Silicon Tracking System CBM-MPD STS Consortium Y. Murin Engineering of STS modules & stations

7 J.M. Heuser − Status of the Silicon Tracking System Building on technology developed for the ALICE Strip Tracker module ALICE ITS carbon fiber structure front view of a (half)-station front top view of a station STS – mechanical support Consortium - S. Igolkin, StPbU

8 J.M. Heuser − Status of the Silicon Tracking System STS assembly details attaching sensors to carbon fibre support

9 J.M. Heuser − Status of the Silicon Tracking System STS ladder assembly

10 J.M. Heuser − Status of the Silicon Tracking System STS ladder mockup

11 J.M. Heuser − Status of the Silicon Tracking System Front-end board bump-bonded low-power FE chip on a high-density circuit Readout cables * 4-layer * Al-14  m on Kapton-10  m * Shield + spacer layer * 1024 lines, µm pitch * up to 60 cm long Microstrip sensors double sided, CBM01/CBM03 tab-bonding of cables to detectors and front-end board Development of tracking modules

12 J.M. Heuser − Status of the Silicon Tracking System Module demonstrators 1-b'

13 J.M. Heuser − Status of the Silicon Tracking System we have: –work hypothesis of STS layout –emerging engineering solutions on ladder and station construction –beginning prototype work we need: –to consolidate the concept –build proof-of-principle ladder in –matching components –timely availability of components for this work

14 J.M. Heuser − Status of the Silicon Tracking System  Sensors:  6 cm wide;  2-6 cm high;  1024 strips per sensor;  15° stereo angle;  60 µm strip pitch ; 14 STS station layout and simulation of the hit recognition performance A. Kotynia

15 J.M. Heuser − Status of the Silicon Tracking System 15 Complete chain of physical processes caused by charged particle traversing the detector Magnetic field influences collection of the charge on the strips |B| = 1T Holes:  = 1.5°  x = 8  m Electrons  = 7.5°  x = 40  m Realistic STS Digitizer Particle position in the sensor is obtained by using Center Of Gravity algorithm: Random noise is added according to a Gaussian distribution with standard deviation as an equivalent noise charge of the detector system

16 J.M. Heuser − Status of the Silicon Tracking System STS Digitizer – collected charge per strip 16

17 J.M. Heuser − Status of the Silicon Tracking System Hit Finding Efficiency 17 large incidence angle

18 J.M. Heuser − Status of the Silicon Tracking System Channel dead time simulations For minimum bias Au+Au collision at 25AGeV channel occcupancy: Station min occ max occ Channel dead time Channel occupancy Hit finding efficiency occ>3.0 % (<1% of all chips) 1.0 % 3.0 % (12% of all chips) occ<1.0 % (88% of all chips) Probability of channel inefficiency 100 ns>3 % 1-3% < 1%89.94 % 500 ns>15 %5-15 %< 5 %83.37 % 1000 ns>30 % % <10 %78.25 % 0 ns91.17 %

19 J.M. Heuser − Status of the Silicon Tracking System 19 Parameters set in simulation ke - per ADC channel Hit finding efficiency Th: 4ke- Nof bitsStep 4-bits % 5-bits bits % 7-bits bits % 20-bits % 19 ADC resolution

20 J.M. Heuser − Status of the Silicon Tracking System we have: –realistic model of the STS –various varations to it –insight in effects on the hit finding efficiency and creation of data volume we need: –to further optimize the overall system –station layout –use the reconstructed hits or hit channels efficiently in the tracking –(interface optimization, new stations,...) overall performance counts

21 J.M. Heuser − Status of the Silicon Tracking System 15 th CBM collaboration meeting, April 12 th, 2010 Performance test of STS demonstrators A. Lymanets

22 J.M. Heuser − Status of the Silicon Tracking System FEB rev. B: Every second channel bondable. Still good for lab tests for timing studies or ADC response (without clustering). FEB rev. C: All channels are usable But thermal stability becomes an issue. Detector-FEB cable: Turns out to work if shielded properly. Detectors of CBM01 and CBM02 type “behave” similarly (bad), poor charge collection at n-sides. FEB 4nx: Cooling plates improve thermal stability Problems with surviving potential of the chips on board. Beam time : vastly different count rates in different stations caused by the beam.

23 J.M. Heuser − Status of the Silicon Tracking System Energy calibration with 241 Am Using 300 μm pitch detector => no significant charge sharing Energy gain = e - /ADC cnt + one can obtain pedestal energy (not necessarily zero) Noise 460 e 6 pF

24 J.M. Heuser − Status of the Silicon Tracking System Calibration line Energy calibration is obtained, but extrapolated pedestal amplitude is ~3 kElectrons. Possible reasons: non-linearity, bias due to peak detector.

25 J.M. Heuser − Status of the Silicon Tracking System n-XYTER chip Input pads Output pads Power lines current Channel 127 Channel 0 Test channel

26 J.M. Heuser − Status of the Silicon Tracking System Pedestal profile over channels Pedestal “sag” is observed with maximum in channel #64  To be addressed in the upcoming engineering run done in Heidelberg Univ. (H. K. Soltveit) Crosstalk problem digital crosstalk – on the chip, not just directly between channels

27 J.M. Heuser − Status of the Silicon Tracking System we have: –experience with the first complete system chains –developed lots of tools –but also destroyed equipment we need: –more objects, material, experienced fellows –built new tracking modules –overcome technology problems (e.g. PCBs at cutting edge designs) –thorough long-term tests

28 J.M. Heuser − Status of the Silicon Tracking System Status of Front End Electronics: n-XYTER PCBs & Power Supply V. Kleipa

29 J.M. Heuser − Status of the Silicon Tracking System N-XYTER FEB rev. D Modifications w.r.t. FEB_C: Increased NXYTER bond pitch 0.3V drop LDOs used Separated supply regulators PT100 sensor out Alternative connector for separated LVDs and common mode signals Testpoints New power connector I2C and SPI spike filter I2C reads now: Temperature Current Testchannels Slow, Fast I2C RW: Serial EEprom for data storage 20 specimen under construction wire-bonding: C. Simons

30 J.M. Heuser − Status of the Silicon Tracking System n-XYTER PCB Cooling Plate Cooling Block for FEB_B, FEB_C and FEB_D Design by Carmen Simons C. Simons

31 J.M. Heuser − Status of the Silicon Tracking System n-XYTER Demonstrator r/o board Input pitch 100um PCB size 65mm x 80mm Cooling of 14W power with bottom copper or Al plate ADC device on bottom side Ext. power supply regulation Open task: Staggered NXYTER bonds to one layer input fan Data output connection

32 J.M. Heuser − Status of the Silicon Tracking System FEE boards are critical for system studies we have: –hopefully now a reasonably stable board (rev. D) we need: –to move from 1-chip general purpose board (n-XYTER) to intermediate 4-chip board for ladder tests (n- XYTER) to develop a concept and build a prototype of the 8- chip board (STS-XYTER) to do this: strengthen the team

33 J.M. Heuser − Status of the Silicon Tracking System Development of microstrip detectors J. Heuser

34 J.M. Heuser − Status of the Silicon Tracking System CBM01 (2007) CBM02 (2010) close-up of a corner of CBM01 (2008) CBM03 CBM04 (parallel: ISTC01) GSI-CiS Erfurt

35 J.M. Heuser − Status of the Silicon Tracking System Close-up of a corner of CBM03

36 J.M. Heuser − Status of the Silicon Tracking System we have: –essentially one vendor/production partner (CiS) –used CBM01 and CBM02 for prototyping work –indications that the charge collection is not fully efficient and understood –set up framework for TCAD simulations we need: –to verify the charge collection properties –overcome stability issues –to set up a systematic characterization, new material coming (CBM03, CBM04) –systematic irradiation studies

37 J.M. Heuser − Status of the Silicon Tracking System Development of radhard microstrip detectors S. Chatterji

38 J.M. Heuser − Status of the Silicon Tracking System 3D strip detector simulation model X-Y plane of the 3D grid. One can see there is a stereo angle on either side of  3-D TCAD simulation tools “SYNOPSYS”  Sub packages  Sentaurus  Inspect  Tecplot  SPICE (Mixed Mode)

39 J.M. Heuser − Status of the Silicon Tracking System Some Static Characteristics  C Total = C back +2*C int  ENC α C Total  Optimization needed to maximize breakdown voltage & minimize ENC

40 J.M. Heuser − Status of the Silicon Tracking System Optimizations of the detector design strip pitch and widthstrip insulation

41 J.M. Heuser − Status of the Silicon Tracking System Impact of Radiation Damage * * CiOi Ev+0.36Donor * * VVVEc-0.46Acceptor * * VVEc-0.42Acceptor η (cm -1 )σ h (cm 2 )σ e (cm 2 )Trap Energy (eV)Type  V BD ↑ with fluence  Current ↑ by 3 orders  R int ↓ with fluence  Detailed study needed

42 J.M. Heuser − Status of the Silicon Tracking System Full system simulation transient signal behavior in the detector and in the readout cable

43 J.M. Heuser − Status of the Silicon Tracking System Beam pipe options in STS S. Belogurov

44 J.M. Heuser − Status of the Silicon Tracking System Be: 4 LHC experiments, Belle, Cleo, CDF etc mm typical thickness Al: HERAb 0.3 mm with stiffening ribs. Information availabe, seems reproducible Relevant background for window: LHCb VELO (Ø800 mm 2 mm Al alloy), machined from a forged billet together with the bellow. SF for the LHCb Be beam pipe is 4-6, for window ~ 3 SF for the HERAb beampipe is ~2

45 J.M. Heuser − Status of the Silicon Tracking System “ Ideal ” configurations. Effects: cylinder-cone; Be-Al. Al: window – scaling from VELO, cone – “simple” manufacturing. “Realistic” configurations. Effects of bellows, width of “Tube”. 1.6º configuration fits to ladders of S. Igolkin without cutting the central rib. Studied configurations Any configuration has a weld 1x10 mm Remarks. 1) 0.3 mm Al = 0.5 mm Be 2) Competition works: JSC “Kompozit” started to think about 0.4 mm Be pipe

46 J.M. Heuser − Status of the Silicon Tracking System Results for UrQMD central events at 25 AGeV window welding Range distribution

47 J.M. Heuser − Status of the Silicon Tracking System Results for UrQMD central events at 25 AGeV /c No pipe Comparison of Al and Be cones No pipe Lambda  p pi- K0  pi+ pi- done as well for tubes  Al tube will do ? System engineering, workshop in Fall 2010?

48 J.M. Heuser − Status of the Silicon Tracking System Project plan, iMoU, Writeups, TDR Request by the Technical Coordinator: Comprehensive Sub-System Note during Q Design Review during Q (CBM organized, external Reviewers) TDR's in Q Project plan within Interim Memorandum of Understanding DRAFT – being updated Participating Institutes Work share during R&D phase, Construction phase less clear Tasks, timelines and deliverables not covered tasks + teams Costs STS construction + commissioning timeline: adapt to new FAIR schedule

49 J.M. Heuser − Status of the Silicon Tracking System Test beam at GSI, June 2010 preliminary – beam scheduling meeting on 19 April cave C beam line HTD beam: Nitrogen 0.8 GeV/u on a target