1. JLC CCD Vertex Detector R&D Y. Sugimoto KEK 2003. 8. 19

2. Members KEKA. Miyamoto, K. Nakayoshi, Y. Sugimoto, H. Yamaoka KEKA. Miyamoto, K. Nakayoshi, Y. Sugimoto, H. Yamaoka Niigata U.K. Fujiwara, G. Iwai, Y. Onuki, N. Tamura, H. Takayama Niigata U.K. Fujiwara, G. Iwai, Y. Onuki, N. Tamura, H. Takayama Saga U.T. Kuniya, K. Nakamura, K.D. Stefanov, T. Tsukamoto Saga U.T. Kuniya, K. Nakamura, K.D. Stefanov, T. Tsukamoto Tohoku U.T. Nagamine, Y. Shirasaki Tohoku U.T. Nagamine, Y. Shirasaki Tohoku Gakuin U.K. Abe Tohoku Gakuin U.K. Abe Toyama CollegeT. Aso Toyama CollegeT. Aso of Maritime Tech. Red names: Graduated or left ( 4 Ms and 1 D)

3. Contents Introduction Introduction Possible Options Possible Options Why CCD? Why CCD? R&D Program R&D Program What has been achieved? What has been achieved? What has been left to be done? What has been left to be done? Future Prospects Future Prospects

4. Possible Options Candidates for Vertex Detectors at LC Candidates for Vertex Detectors at LC Silicon Strip Detector --- Occupancy Silicon Strip Detector --- Occupancy Hybrid Active Pixel Sensor --- Thickness Hybrid Active Pixel Sensor --- Thickness Charge Coupled Device (CCD) Charge Coupled Device (CCD) Monolithic Active Pixel Sensor (CMOS) Monolithic Active Pixel Sensor (CMOS) Other New Ideas (DEPFET, SOI, etc.) Other New Ideas (DEPFET, SOI, etc.)

5. DEPFET p+ n+ rear contact drainbulksource p s y m m e t r y a x i s n+ n internal gate top gateclear n - n+ p+ - - + + + + - MIP 50 µm - - -- -- ~1µm

6. Why CCD? Mission: Show a design by the end of 2000 (ACFA Report) Mission: Show a design by the end of 2000 (ACFA Report) Structure of CCD Structure of CCD Diffusion of electrons in epitaxial layer Diffusion of electrons in epitaxial layer Key of excellent spatial resolution Key of excellent spatial resolution for CCD & CMOS pixel sensors for CCD & CMOS pixel sensors Takes time to diffuse Takes time to diffuse d = sqrt(Dt) ~ 6  m @ t=10ns d = sqrt(Dt) ~ 6  m @ t=10ns  OK for JLC/NLC (Fully depleted CCD at TESLA) (Fully depleted CCD at TESLA) CCD has simple structure CCD has simple structure Large area sensor Large area sensor High yield High yield  CCD is the most feasible option

7. CCD MAPS HAPS DEPFET CCD MAPS HAPS DEPFET ResolutionAAA AAA A A Thin material AAA AAA C AA Rad. Hardness A(?) AA AAA AAA(?) Large waferAAA ? ? ?

8. R&D Program Design Criteria : Design Criteria : “The Highest Vertex Resolution with Technical Feasibility” “The Highest Vertex Resolution with Technical Feasibility” High spatial resolution of the sensor High spatial resolution of the sensor Minimize multiple scattering  Thin wafer Minimize multiple scattering  Thin wafer Close to the IP  Radiation Hardness Close to the IP  Radiation Hardness Room temperature operation, if possible Room temperature operation, if possible

9. Spatial Resolution Beam Tests in ’ 97 and ’ 98 Beam Tests in ’ 97 and ’ 98 KEK PS T1 beam line KEK PS T1 beam line 0.5 – 2.0 GeV/c pion 0.5 – 2.0 GeV/c pion 4-CCD Telescope 4-CCD Telescope CCD Samples: HPK 24  m 2 10/50  m epi. EEV 22  m 2 20  m epi. CCD Samples: HPK 24  m 2 10/50  m epi. EEV 22  m 2 20  m epi. Resolution better than Resolution better than 3  m(r.m.s) was obtained 3  m(r.m.s) was obtained Excellent spatial resolution of CCD has been demonstrated.

10. Spatial Resolution (Cont.) Resolution Study with Laser Beam Scanner (Niigata U.) Resolution Study with Laser Beam Scanner (Niigata U.) Beam spot size: 2  m Beam spot size: 2  m  532 nm / 1064 nm  532 nm / 1064 nm IR(1064nm) Laser IR(1064nm) Laser simulates MIP simulates MIP Quick study possible Quick study possible Study of charge spread Study of charge spread

11. Laser Scanner Laser Scanner 532 nm 1064 nm

12. Thin Wafer CCD has sensitive thickness ( = epitaxial layer thickness) of ~20  m CCD has sensitive thickness ( = epitaxial layer thickness) of ~20  m Can be thinned down to 20  m Can be thinned down to 20  m if mechanically OK if mechanically OK Several ideas: Several ideas: Thin wafer stretched by tension Thin wafer stretched by tension Thin wafer glued on Be support Thin wafer glued on Be support Partially thinned wafer --- Our study Partially thinned wafer --- Our study

13. Partially Thinned Wafer Picture Frame Type Picture Frame Type Sample wafer : Sample wafer : Back illumination CCD Back illumination CCD System for flatness measurement constructed System for flatness measurement constructed Non-flatness has been measured Non-flatness has been measured  Poor Flatness

15. Honeycomb & Grid Type Honeycomb & Grid Type Average thickness = 76  m = 76  m = 100  m (including edge) = 100  m (including edge) ~0.1% X 0 ~0.1% X 0 ANSYS analysis: ANSYS analysis:material~1/3  rigidity~1/3 Simple plate: Simple plate: thickness 1/3  rigidity 1/27 Models for ANSYS

16. Radiation Hardness of CCDs Radiation Damage on CCDs Radiation Damage on CCDs Surface Damage: Charge build-up in SiO 2 and SiO 2 -Si interface by dE/dx Surface Damage: Charge build-up in SiO 2 and SiO 2 -Si interface by dE/dx Increase of surface dark current Increase of surface dark current Shift of operation voltage (Flat-band Voltage Shift) Shift of operation voltage (Flat-band Voltage Shift) Bulk Damage: Displacement in lattice Bulk Damage: Displacement in lattice Increase of bulk dark current Increase of bulk dark current Charge Transfer In-efficiency (CTI) Charge Transfer In-efficiency (CTI)

17. Dark Current and Flat-band Voltage Shift Dark Current and Flat-band Voltage Shift HPK S5466 irradiated with 10mCi Sr-90  -source HPK S5466 irradiated with 10mCi Sr-90  -source No bias during irradiation Biased during irradiation

18. Study of CTI Study of CTI HPK S5466 and EEV CCD02-06 irradiated with Sr-90  -source and Cf-242 n-source HPK S5466 and EEV CCD02-06 irradiated with Sr-90  -source and Cf-242 n-source Read-out cycle = 3 sec (250 kHz) Read-out cycle = 3 sec (250 kHz) CTI looks decreasing at higher temperature because of increase of dark current which fill-up the traps. CTI looks decreasing at higher temperature because of increase of dark current which fill-up the traps. (EEV CCD showed much worse CTI due to less dark current) (EEV CCD showed much worse CTI due to less dark current)  NOT expected at JLC where Tcyc=6ms and much less dark current  Fat-zero charge injection (~1000 e) is desirable HPK S5466

19. Other CTI Improvements Other CTI Improvements Notch Channel CCD Notch Channel CCD High speed readout : Horizontal CTI is expected prop. to 1/f High speed readout : Horizontal CTI is expected prop. to 1/f

20. Conclusion from Radiation Damage Study Conclusion from Radiation Damage Study Surface damage NOT problem in MPP mode operation and 6ms cycle time Surface damage NOT problem in MPP mode operation and 6ms cycle time CTI study + Beam Background Simulation CTI study + Beam Background Simulation  CCD can be used for 3 years with  CCD can be used for 3 years with - B=2T, R=24mm - B=2T, R=24mm - JLC A-Option - JLC A-Option - Notch channel - Notch channel - Fat-zero charge injection - Fat-zero charge injection - assuming that effect of H.E. electrons is 10 times stronger than Sr-90  -source - assuming that effect of H.E. electrons is 10 times stronger than Sr-90  -source BUT large ambiguity in E-dependence of electron damage and neutron background level.

21. Model Calculation of NIEL Model Calculation of NIEL Bulk damage is thought to be proportional to Non-Ionizing Energy Loss (NIEL) Bulk damage is thought to be proportional to Non-Ionizing Energy Loss (NIEL) Sr-90 LC pair background

22. R&D Items left to be done Spatial Resolution Spatial Resolution Study of resolution of radiation-damaged CCD Study of resolution of radiation-damaged CCD Study of charge diffusion in epi. layer Study of charge diffusion in epi. layer Thin Wafer Thin Wafer Try to get sample wafers of Honeycomb/Grid type Try to get sample wafers of Honeycomb/Grid type

23. R&D Items left to be done (Cont.) Radiation Hardness Study Radiation Hardness Study Study of energy dependence of bulk damage Study of energy dependence of bulk damage High energy (150MeV) electron irradiation at Tohoku Univ. High energy (150MeV) electron irradiation at Tohoku Univ. Study of characteristics of irradiated CCDs Study of characteristics of irradiated CCDs I d vs. Temp I d vs. Temp Flat-band Voltage Shift Flat-band Voltage Shift CTI vs. Temp CTI vs. Temp CTI vs. Readout frequency  cPCI DAQ System CTI vs. Readout frequency  cPCI DAQ System CTI vs. Fat-zero charge: Injection of controlled amount of charge CTI vs. Fat-zero charge: Injection of controlled amount of charge CTI vs. clock pulse width/height CTI vs. clock pulse width/height Annealing/anti-annealing Annealing/anti-annealing

24. R&D Items left to be done (Cont.) Simulation studies concerning Vertex det. Simulation studies concerning Vertex det. Background study using Full Simulator (JIM, JUPITER) Background study using Full Simulator (JIM, JUPITER) Crossing angle: 7 mrad  20 mrad Crossing angle: 7 mrad  20 mrad Physics study using Quick Simulator Physics study using Quick Simulator Physics and Detector study using Full Simulator Physics and Detector study using Full Simulator

25. Future Prospects FY2003-FY2004 FY2003-FY2004 Continue jobs left to be done Continue jobs left to be done  Find out the best design and operating condition of CCD vertex detector Prepare for the next step Prepare for the next step Conceptual design of prototype ladder (with HPK) Conceptual design of prototype ladder (with HPK) Find out the financial source Find out the financial source Japan-US, KAKENHI, or KEK GAISAN-YOUKYU ? Japan-US, KAKENHI, or KEK GAISAN-YOUKYU ? FY2005- The Next Step FY2005- The Next Step Construction of prototype ladder Construction of prototype ladder

26. Future plan in FY2005~ Custom made CCDs with Custom made CCDs with Reduced material ( honeycomb type? ) Reduced material ( honeycomb type? ) > 20MHz readout speed > 20MHz readout speed Multiple readout nodes Multiple readout nodes Notch structure Notch structure Charge injection capability Charge injection capability Readout by ASIC with multi-channel CDSs, Amplifiers, ADCs, and a Multiplexer Readout by ASIC with multi-channel CDSs, Amplifiers, ADCs, and a Multiplexer

27. Multi-Thread CCD Normal CCD: Normal CCD: Many V-shifts  Sig. Loss Many V-shifts  Sig. Loss CPCCD: CPCCD: Limited space for r.o.elec. Limited space for r.o.elec. Multi-port CCD with few tens of V-shifts : MTCCD Multi-port CCD with few tens of V-shifts : MTCCD Can be used as a high speed CCD camera Can be used as a high speed CCD camera HPK says “ Challenging but not impossible ” HPK says “ Challenging but not impossible ”

28. Conclusion Feasibility of the baseline design of a CCD Vertex Detector has been established. Feasibility of the baseline design of a CCD Vertex Detector has been established. R=24, 36, 48, 60 mm R=24, 36, 48, 60 mm  < 4  m  < 4  m Thickness = 300  m /layer Thickness = 300  m /layer    b = 7 + 20/(p  sin 3/2  m To get better performance, studies to get To get better performance, studies to get Rin < 24 mm (  Radiation hardness) Rin < 24 mm (  Radiation hardness) Thickness << 300  m Thickness << 300  m will be continued. A milestone is  b = 5 + 10/(p  sin 3/2  m Eventually, we have to make a prototype ladder to demonstrate the required performance. (  need \) Eventually, we have to make a prototype ladder to demonstrate the required performance. (  need \)

29. Appendix Situation in Europe Situation in Europe LCFI Group (UK) : R&D for Column Parallel CCD LCFI Group (UK) : R&D for Column Parallel CCD 2.26M£ from PPARC (UK): 2002, 2003, 2004 (3y) 2.26M£ from PPARC (UK): 2002, 2003, 2004 (3y) Approved as DESY PRC R&D 01/01 Approved as DESY PRC R&D 01/01 MAPS Group (CMOS) MAPS Group (CMOS) DESY PRC R&D 01/04 DESY PRC R&D 01/04 DEPFET DEPFET DESY PRC R&D 03/01 DESY PRC R&D 03/01 SiLC, CALICE, TPC, -----, submitted proposals to DESY PRC SiLC, CALICE, TPC, -----, submitted proposals to DESY PRC