1. Status of the Micro Vertex Detector M. Deveaux, Goethe University Frankfurt for the CBM-MVD collaboration

2. The CBM-MVD M. Deveaux 2 CBM We are here

3. How will it look M. Deveaux 3 Magnet Silicon Tracking System DAQ cards Vacuum vessel MVD - planes

4. M. Deveaux, 4 Open charm reconstruction: Concept Primary Beam: 25 AGeV Au Ions (up to 10 9 /s) Primary vertex Secondary vertex Short lived particle D 0 (c  = ~ 120 µm) Detector 1 Detector2 Target (Gold) z Reconstruction concept for open charm Central Au + Au collision (25 AGeV) A good time resolution to distinguish the individual collisions (few 10 µs) Very good radiation tolerance (>10 13 n eq /cm²) Reconstructing open charm requires: Excellent secondary vertex resolution (~ 50 µm) => Excellent spatial resolution (~5 µm) => Very low material budget (few 0.1 % X 0 ) => Eventually: Detectors in vacuum

5. 5 Status of the sensors (last meeting 2011) M. Deveaux CBM SIS300 MAPS* (2003) MAPS* (2011) MIMOSA-26 (2010) Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²1x10 13 n eq 10 13 n eq Rad. hard. io > 3 Mrad200 krad> 1 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Monolithic Active Pixel Sensors (MAPS, also CMOS-Sensors) Invented by industry (digital camera) Modified for charged particle detection since 1999 by IPHC Strasbourg Also foreseen for ILC, STAR, ALICE… => Sharing of R&D costs.

6. A word on simulation 6 M. Deveaux

7. Global design: How many MVD stations? M. Deveaux 7 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

8. Global design: How many MVD stations? M. Deveaux 8 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

9. Global design: How many MVD stations? M. Deveaux 9 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

10. Global design: How many MVD stations? M. Deveaux 10 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

11. Global design: How many MVD stations? M. Deveaux 11 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

12. Global design: How many MVD stations? M. Deveaux 12 5 cm Target MVD 1MVD 2 STS 1STS 2STS 3 Vacuum window Tracking, artist view

13. L1 “MVD track finding efficiency” vs. MVD design 13 MVD track finding efficiency[%] 2 MVD stations 3 MVD stations 4 MVD stations 5 10 Nonepile up 100% = primary tracks, geo- metrically accepted by MVD, > 4 hits in STS 90 50 Tracking efficiency = 83% for standard MVD, drops to <55% at pile up 10 Tracking efficiency is substantially improved by additional stations Impact for 4 th station to be studied in detail M. Deveaux C. Trageser

14. Background rejection capabilities of the MVD 14 0 50 None510 accepted BG-tracks / event Bad reconstruction Some bad hits Good track finding Not accepted Cuts: p >1 GeV pt>0.3 GeV Long (>4 in STS) IP<600µm IP/  IP >6 M. Deveaux More than 2 MVD stations are needed for BG rejection Expect good sensitivity for open charm with >3 stations C. Trageser

15. Sensor R&D M. Deveaux 15 for (Int_t Mimosa=1; true; Mimosa++) { Build_Next_Prototype (Mimosa); Test_Prototype (Mimosa); Enjoy_Spectacular_Progress_Of(Mimosa); ImproveDesign(Mimosa);}

16. Long standing believes vs. technological progress 16 A small pixel pitch is needed to reach the radiation tolerance needed for CBM CBM goal M. Deveaux

17. 17 Sensor R&D: The operation principle Reset +3.3V Output SiO 2 N++ N+ P+ P- P+ 15µm 50µm

18. 18 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output SiO 2 N++ N+ SiO 2 P++ GND +3.3V Non-ionising radiation Energy deposit into crystal lattice

19. 19 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output SiO 2 N++ N+ SiO 2 P++ GND +3.3V Key observation: Signal amplitude is reduced by bulk damage

20. 20 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output SiO 2 N++ N+ SiO 2 P++ GND +3.3V Electric field increases the radiation hardness of the sensor Draw back: Need CMOS-processes with low doping epitaxial layer E

21. Long standing believes vs. technological progress 21 A small pixel pitch is needed to reach the radiation tolerance needed for CBM MIMOSA-32: 20x40µm² pixel 99.5% D. Doering et al. – Mimosa18 AHR CBM goal M. Deveaux

22. 22 Status of the sensors (last meeting 2011) M. Deveaux CBM SIS300 MAPS* (2003) MAPS* (2011) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²>1x10 13 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 1 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Monolithic Active Pixel Sensors (MAPS, also CMOS-Sensors) Invented by industry (digital camera) Modified for charged particle detection since 1999 by IPHC Strasbourg Also foreseen for ILC, STAR, ALICE… => Sharing of R&D costs.

23. 23 Update on sensor R&D M. Deveaux CBM SIS300 MAPS* (2003) MAPS* (2013) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²>3x10 14 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 1 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Monolithic Active Pixel Sensors (MAPS, also CMOS-Sensors) Invented by industry (digital camera) Modified for charged particle detection since 1999 by IPHC Strasbourg Also foreseen for ILC, STAR, ALICE… => Sharing of R&D costs.

24. Challenge: Find MAPS-compatible 0.18µm CMOS process 32 mm² surface Radiation tolerance of MAPS 24 So far - Radiation tolerance limited by: Leakage current – noise Conduction channels between transistors (?) DONE First prototype: MIMOSA-32 32 different kinds of pixels 32 µs readout time 33 mm² Known solution: Use 0.18 µm CMOS instead of 0.35µm CMOS M. Deveaux

25. Long standing believes vs. technological progress 25 A small pixel pitch is needed to reach the radiation tolerance needed for CBM MIMOSA-32: 20x40µm² pixel 99.5% CBM goal Mimosa-32, 20x40µm² pitch (Beam test @ SPS by IPHC, preliminary) 99.5% detection efficiency After 10 13 n eq /cm²+ 1 MRad ! M. Deveaux

26. Long standing believes vs. technological progress 26 MIMOSA-32: 20x40µm² pixel 99.5% CBM goal Mimosa-32, 20x40µm² pitch (Beam test @ SPS by IPHC, preliminary) 99.5% detection efficiency After 10 13 n eq /cm²+ 1 MRad ! A small pixel pitch is needed to reach the radiation tolerance needed for CBM M. Deveaux

27. Why is this important? 27 Pixel with pedestal correction ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zero suppressed) 50 µs/frame25 µs/frame 12 µs/frame ~2000 20x20µm²20x40µm² Requires 0.18µm CMOS Test chip submitted M. Deveaux

28. Why is this important 28 Pixel with pedestal correction ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zero suppressed) 50 µs/frame25 µs/frame 12 µs/frame ~2000 20x20µm²20x40µm² Requires 0.18µm CMOS Test chip submitted M. Deveaux MAPS are too slow for CBM

29. Why is this important 29 There is a clear strategy for reaching the readout speed needed for CBM Pixel with pedestal correction ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zero suppressed) 50 µs/frame25 µs/frame 12 µs/frame ~2000 20x20µm²20x40µm² Requires 0.18µm CMOS Test chip submitted M. Deveaux

30. 30 Update on sensor R&D M. Deveaux CBM SIS300 MAPS* (2003) MAPS* (2013) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²>3x10 14 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 1 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Monolithic Active Pixel Sensors (MAPS, also CMOS-Sensors) Invented by industry (digital camera) Modified for charged particle detection since 1999 by IPHC Strasbourg Also foreseen for ILC, STAR, ALICE… => Sharing of R&D costs.

31. MIMOSA-32 and ionizing radiation M. Deveaux 31 Noise Sensor irradiated with X-rays @ CERN Noise increases much slower (as expected) Higher initial noise (not expected) D. Doering

32. 32 Sensor R&D: Tolerance to non-ionising radiation +3.3V Output SiO 2 N++ N+ SiO 2 P++ GND +3.3V Study noise with varied size of transistor gate

33. Comparison with 0.18µm vs. AMS 0.35 M. Deveaux 33 D. Doering 0.35 µm, big0.18µm, small 0.18µm, tiny

34. Going into details 34 M. Winter et al.

35. Random Telegraph Signal 35 M. Winter et al. RTS, illustration Sensors see difference between two samples Side peaks due to change of state. Problem understood, => Need bigger gates

36. 36 So what? M. Deveaux CBM SIS300 MAPS* (2003) MAPS* (2013) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²>3x10 14 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 1 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Mimosa-32, 20x20µm² pitch (Beam test @ SPS by IPHC, preliminary) 99.5% det. efficiency (S/N ~30) After 3 MRadat +15°C!

37. M. Deveaux 37 So what? CBM SIS300 MAPS* (2003) MAPS* (2013) MIMOSA-26 Binary, 0 Single point res. ~ 5 µm1.5 µm1 µm4 µm Material budget < 0.3% X 0 ~ 0.1% X 0 ~ 0.05% X 0 Rad. hard. non-io. >10 13 n eq 10 12 n eq /cm²>3x10 14 n eq >10 13 n eq Rad. hard. io > 3 Mrad200 krad> 3 Mrad> 500 krad Time resolution < 30 µs~ 1 ms~ 25 µs110 µs Optimized for one parameter Current compromise Mimosa-32, 20x20µm² pitch (Beam test @ SPS by IPHC, preliminary) 99.5% det. efficiency (S/N ~30) After 3 MRadat +15°C!

38. Next steps in the R&D 38 Pixel with pedestal correction ~1000 discriminators On - chip cluster-finding processor Output: Cluster information (zero suppressed) Prototype MIMOSA-22THR submitted Already excellent but Get rid of RTS 4 prototypes submitted Prototype SUZE - 2 submitted First prototypes in 0.18µm CMOS show spectacular results. Full engineering run (11 CBM relevant prototypes) submitted. More to come => Stay tuned. M. Deveaux

39. How to integrate the sensors? M. Deveaux, CBM Collaboration Meeting, Kolkata, 24-28. Sept 2012 39 MIMOSA-26 (600 kPixel, 10 4 frames/s, zero suppression) Thinned to 50µm, at IKF Frankfurt See next talk (M. Koziel)

40. Summary 40 Sensors for MVD (since 2010) Radiation tolerance (non-io.) was improved by factor 10 Radiation tolerance (io) was improved by factor > 3 All sensor requirements for CBM are individually demonstrated Still room for improvement in 0.18µm process Ongoing effort to combine all functionalities Simulation MVD needs 3 or 4 stations for good performance Prototype and integration: Very promising (see next talk)

41. M. Deveaux, CBM Collaboration Meeting, Kolcata, 24-28. Sept 2012 41 The prototype DAQ at night PICSEL Group IPHC, Strasbourg (sensor R&D + test) Thanks to: S. Amar-Youcef, B. Milanovic, Q. Li (Prototype firmware and analysis)M. Koziel, T.Tischler (mechanical integration)B. Neumann (JTAG slow control), M. Wiebusch (analog electronics)C. Trageser (simulation)C. Schrader (DAQ concept and coordination, now with BOSCH),