1. Welcome The SLHC and Novel Powering Schemes for the CMS Strip Tracker Graduiertenseminar der RWTH Aachen Bad Honnef, 31.08.2009 Lutz Feld, Rüdiger Jussen, Waclaw Karpinski, Katja Klein, Jennifer Merz, Jan Sammet 31.08.2009- 1 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

2. Welcome Outline SLHC – The LHC Luminosity Upgrade Consequences for CMS A new Powering Scheme: DC-DC Conversion System Tests with Present CMS Hardware Summary 31.08.2009- 2 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

3. Welcome Outline 31.08.2009- 3 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B SLHC – The LHC Luminosity Upgrade Consequences for CMS A new Powering Scheme: DC-DC Conversion System Tests with Present CMS Hardware Summary

4. Welcome SLHC – The LHC Luminosity Upgrade Increase peak luminosity by one order of magnitude: 10 34 → 10 35 cm -2 s -1 Increase integrated luminosity: 100 fb -1 /yr → 500 fb -1 /yr Center-of-mass energy remains at 14TeV Upgrade is split into 2 phases UNOSAT Phase 2: Booster → LPSPL (Low Power Superconducting Proton Linac) Proton Synchrotron (PS) → Proton Synchrotron 2 Upgrades of LHC injectors, interaction region... Start operation in 2017-2018 Aim for peak luminosity of L = (8-10)·10 34 cm -2 s -1 Phase 1: Linac2 → Linac4 New collimators for LHC Gradual increase of luminosity Aiming for new peak luminosity L = (2-3)·10 34 cm -2 s -1 in 2016 31.08.2009- 4 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

5. Welcome SLHC Physics Opportunities Higgs Detecting composite Higgs via high-energy WW scattering Detecting rare decays of the Higgs boson Precision measurements of Higgs boson couplings Determination of the Higgs self-coupling Higgs Detecting composite Higgs via high-energy WW scattering Detecting rare decays of the Higgs boson Precision measurements of Higgs boson couplings Determination of the Higgs self-coupling Supersymmetry Extending the reach of superpartner masses Precision measurements of Susy spectrum and couplings Extending the reach for smaller extra dimensions Supersymmetry Extending the reach of superpartner masses Precision measurements of Susy spectrum and couplings Extending the reach for smaller extra dimensions Other potential new physics Extending the reach of quark substructure probes Extending the reach of Z’ and W’ gauge bosons Finding evidence for a hidden/singlet sector Other potential new physics Extending the reach of quark substructure probes Extending the reach of Z’ and W’ gauge bosons Finding evidence for a hidden/singlet sector However:To benefit from a higher luminosity it is regarded as mandatory to at least preserve the performance of the present detectors 31.08.2009- 5 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B © Hamburger Kunsthalle/BPK/Elke Walford

6. Welcome Outline 31.08.2009- 6 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B SLHC – The LHC Luminosity Upgrade Consequences for CMS A new Powering Scheme: DC-DC Conversion System Tests with Present CMS Hardware Summary

7. Welcome The SLHC Detector Environment LHC Peak luminosity: 10 34 cm -2 s -1 Pile up events: 20 on average Fast hadrons per cm 2 : 0.2  10 14 – 32  10 14 31.08.2009- 7 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B SLHC Peak luminosity: 10  10 34 cm -2 s -1 Pile up events: 300 to 400 on average Radiation dose increase by a factor of 6 H  ZZ  eeµµ, 200 pile up events H  ZZ  eeµµ, 20 pile up events LHC SLHC

8. Welcome Consequences for CMS 31.08.2009- 8 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Sub-DetectorChanges for SLHC Muon System Minor detector upgrades (for phase I) Major upgrades of electronics Hadronic Calorimeter Parts of the end caps at high  will have to be replaced New electronics to improve readout speed and trigger granularity In some scenarios the HF would conflict with parts of the accelerator Replace hybrid photo-diodes and photomultipliers (e.g. with SiPM) Electromagnetic Calorimeter In general expected to work under SLHC conditions Adapt off-detector electronics to new bunch structure Performance of end caps may decrease slightly Trigger and DAQ Systems Include tracker data into level-1 trigger to preserve current trigger rate Complete replacement Tracking System Pixel tracker will already be replaced for phase I Present hardware cannot cope with the SLHC environment and will have reached the end of its lifetime in 2018 A complete new tracking system has to be developed and build

9. More complex readout electronics Decrease operating voltage 31.08.2009- 9 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Welcome Developing a new Tracking System ~ 50% of the power consumption of the present tracker is lost in cables Material budget of the tracker is crucial for the detector performance No space for additional power cables or cooling pipes  A new powering scheme seems to be inevitable for the outer tracker For CMS DC-DC conversion has been chosen as the baseline Smaller feature size CMOS process (250nm  130nm) allows to reduce the power consumption per channel Tracker information to be incorparated into level-1 trigger More readout channels Sensitive element size must decrease (occupancy) Number of particles increases by a factor of ~ 20 Total power consumption will rather increase than decrease Higher currents Power losses in cables increase ( ~ I²)

10. Welcome Outline 31.08.2009- 10 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B SLHC – The LHC Luminosity Upgrade Consequences for CMS A new Powering Scheme: DC-DC Conversion System Tests with Present CMS Hardware Summary

11. Welcome DC-DC Conversion P tot = P Module + R Cable I 0 2 DC-DC converter P tot = P Module + R Cable (I 0 /r) 2 Power supplyModulePower supply Module Without converter: With converter: Example: (r = 4, Efficiency  = 80%) without converter:P Cable = 30 kW with converter: P Cable = 2.3 kW  Larger currents or thinner cables possible DC-DC converter SwitchEnergy buffer (Conversion ratio r > 1) 31.08.2009- 11 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

12. Welcome The Buck Converter Energy is stored in a magnetic field (inductor) Converter switches between two states: on / off onoff Common implementaion Combination of an integrated circuit (IC) and external components  IC: switches, feedback network… Here: Commercial device (EQ5382D) from Enpiron f = 4 MHz, V in = 2.4-7.0V, footprint: 5mm x 4mm  External: inductor, programming resistors, capacitors… in out 31.08.2009- 12 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Duty cycle g = t on /T (0<g<1) Conversion ratio r = V in /V out (r>1) g  1/r(for lossless converter g = 1/r)

13. Little experience with DC-DC converters in particle physics Buck converter is switching device  High efficiencies possible (>80%)  Adds switching noise on power lines Ferrite materials saturate in strong magnetic fields (CMS Tracker: B = 3.8T)  Use of air-core inductors is inevitable  Magnetic fields of air-core inductors spread wider  Higher risk of noise radiation Converters save cables but add additional material as well Little experience with DC-DC converters in particle physics Buck converter is switching device  High efficiencies possible (>80%)  Adds switching noise on power lines Ferrite materials saturate in strong magnetic fields (CMS Tracker: B = 3.8T)  Use of air-core inductors is inevitable  Magnetic fields of air-core inductors spread wider  Higher risk of noise radiation Converters save cables but add additional material as well Welcome Challenges and Activities 31.08.2009- 13 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Radiation hard converter chip does not exist yet Measure converter noise spectra and efficiencies Simulate material budget for different powering schemes System tests with commercial DC-DC converters and present CMS hardware  Evaluate additional noise  Understand noise propagation  Remove additional noise Measure converter noise spectra and efficiencies Simulate material budget for different powering schemes System tests with commercial DC-DC converters and present CMS hardware  Evaluate additional noise  Understand noise propagation  Remove additional noise Under development by CERN Electronics Group Develop a converter PCB that is very efficient, super light and causes no additional noise

14. Welcome Outline 31.08.2009- 14 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B SLHC – The LHC Luminosity Upgrade Consequences for CMS A new Powering Scheme: DC-DC Conversion System Tests with Present CMS Hardware Summary

15. Module Hybrid 4 or 6 read-out chips (APV) per hybrid 128 silicon strips per APV Analogue, optical read-out Voltages: 1.25 V und 2.5 V Power consumption: ca. 300 mW per APV APV End Cap Petal CMS Welcome CMS 31.08.2009- 15 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

16. The lab TEC petal with InterConnect Board (ICB) Four ring-6 modules powered & read out Petal housed in grounded metal box Official DAQ software Converter integrated via adapter PCB between ICB and sensor module Welcome System Test Set-Up Front Petal ICB Modules 6.1 6.26.3 6.4 31.08.2009- 16 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

17. Integration PCB: “L Type” Measures 30mm x 35 mm in size Hosts 2 converters and inductors to provide provides 1.25V and 2.5V WelcomeConverter Chip EQ5382D from Enpirion Front Petal ICB DC-DC Converters Modules 6.1 6.26.3 6.4 31.08.2009- 17 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Solenoidal inductorEnpirion converter chip

18. WelcomeConverter Chip EQ5382D from Enpirion 31.08.2009- 18 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Converter increases module noise significantly Solenoidal inductors cause even more noise (not shown) Edge strips are most sensitive Converter increases module noise significantly Solenoidal inductors cause even more noise (not shown) Edge strips are most sensitive Without converter L Type PCB with toroids

19. Only 1 chip per PCB (instead of 2) Simplified layout / less probing contacts Reduced PCB size Modular design Smaller inductors Toroid Mini toroid Tiny toroid L = 0.6µH, m=0.8g L=0.6µH, m=0.3g L=0.2µH, m=0.2g 2 instead of 4 layers WelcomeImproving the PCB Design Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 19 - Minimize potential interferences Remove potential crosstalk between input and output Shrink potential feedback loops Easier tests of different filter devices Reduce radiative noise Reduce material budget “AC2_classic” “L Type” “AC2_IDC” (with special capacitors)

20. Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 20 -  The better result is always achieved with miniTors  The new AC2_classic PCBS are slightly better than the modified L type  Special capacitors help to reduce the noise significantly  The better result is always achieved with miniTors  The new AC2_classic PCBS are slightly better than the modified L type  Special capacitors help to reduce the noise significantly AC2_IDC L type Different lengths of the PCBs are compensated with additional connector plugs Without converter miniTor tinyTor WelcomeModule Noise with the New PCBs AC2_classic Noise of edge strips [ADC counts]

21. WelcomeLow DropOut Regulator and Pi-Filter PCBs Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 21 - Low DropOut Regulator (LDO) Pi filter Improve the noise performance of the converter PCBs  Two different approaches: C1=C2=22µF L1=2.5nF (R DC  ≤5m  ) f cut  1MHz C1=C2=2.2µF L1=2.5nF (R DC ≤ 5m  ) f cut  3MHz F2 F1 5mV dropout Converts voltage fluctuations into heat (dropout) Radiation hard device does not exist yet Costs efficiency ( ~ %) to be operated and due to dropout Simple (and radiation hard) device Only passive components Costs almost no efficiency ( ~ ‰)

22. WelcomeEffect of LDO and Filter Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 22 - Without converter AC2_classic AC2_IDC No filterF1F2LDO  Pi filters and LDOs reduce the noise considerably  Pi filters are even slightly better than LDOs  With filters almost no additional noise visible  miniTor lead to further improvements (see next slide)  Pi filters and LDOs reduce the noise considerably  Pi filters are even slightly better than LDOs  With filters almost no additional noise visible  miniTor lead to further improvements (see next slide)

23. WelcomeDifferent Conversion Ratios Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 23 - Without converter L type (internal inductors) AC2_classic + mini toroids AC2_classic + mini toroids + F2  An input voltage of 7V corresponds to conversion ratios of 2.8 and 5.6  Noise of the new PCB is more independent from the input voltage  Pi filters reduce noise to the baseline level throughout the accessible voltage range  An input voltage of 7V corresponds to conversion ratios of 2.8 and 5.6  Noise of the new PCB is more independent from the input voltage  Pi filters reduce noise to the baseline level throughout the accessible voltage range

24. Welcome Summary 31.08.2009- 24 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B In about 10 years, the SLHC is hoped to provide an instantaneous luminosity of 10 35 cm -2 s -1 To benefit from the luminosity upgrade, CMS has to maintain its performance DC-DC conversion is the present base line solution for a new CMS powering scheme System tests with current CMS hardware and DC-DC converters have been performed successfully Results so far are quite promising: with a commercial converter chip our PCBs provide a conversion ratio of up to 5.6 without causing any additional noise We are looking forward to continue our tests with radiation hard converter ASICs developed at CERN

25. Back-Ups 31.08.2009- 25 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

26. Welcome How to increase the peak luminosity N b number of particles per bunch n b number of bunches f r revolution frequency  n normalised emittance  * beta value at Ip F reduction factor due to crossing angle N b,  n injector chain  * LHC insertion F beam separation schemes n b electron cloud effect 31.08.2009- 26 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

27. Welcome Luminosity Roadmap Early operation Collimation phase 2 Linac4 and IR upgrade phase 1 New injectors and IR upgrade phase 2 Normal ramp No SLHC phase 2 Peak luminosity 10 34 cm -2 s -1 1/fb Integrated luminosity 31.08.2009- 27 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

28. Welcome Present LCH Upgrade Scenarios NominalUltimate Early Separation Full Crab Crossing Large Piwinski Angle Major Challenge Detector embedded dipoles Crab cavities “Flat” intense bunches Bunch intensity[10 11 ]1.151.7 4.9 Bunch spacing[ns] 25 50 Beta* at IP1&5[m]0.550.50.08 0.25 Crossing angle[µrad]2853150673381 Peak lumi ℒ Average ℒ (turnaround time 10h) [10 34 cm -2 s -1 ] 1.0 0.46 2.3 0.91 15.5 2.4 15.5 2.4 10.7 2.5 Event pile-up1944294 403 F. Zimmermann et al. SLHC Phase I ~ 2014 Alternative Phase II scenarios ( ≥ 2018 ) ~ 2012 31.08.2009- 28 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B

29. Welcome The Buck Converter Energy is stored in a magnetic field (inductor) Converter switches between two states: on / off onoff Common implementaion Combination of an integrated circuit (IC) and external components  IC: switches, frequency generator, feedback network…  External: inductor, programming resistors, capacitors… in out 31.08.2009- 29 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Duty cycle g = t on /T (0<g<1) Conversion ratio r = V in /V out (r>1) g  1/r(for lossless converter g = 1/r)

30. WelcomeImproving the PCB Design Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 30 - ChangeIntention Only 1 chip per PCB (instead of 2) Eliminate potential interferences Simplified layout / less probing contacts Remove potential crosstalk between input and output Reduced PCB sizeShrink potential feedback loops Modular designEasier tests of filter components like the LDO Smaller coils Less radiative noise (more conductive noise if inductance is decreased) 2 instead of 4 layersReduce material budget Name Diameter [mm] Height [mm] Weight [g] Resistance [  ] Inductance [µH] toroid1830.80.30.6 miniTor670.3 0.6 tinyTor640.20.30.2

31. WelcomeNew PCB Layouts: AC2_classic & AC2_IDC Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 31 - AC2_classic 23mm 12mm AC2_IDC 12mm Standard capacitors Inter-Digitated Capacitors (IDC) Capacitors in Reverse Geometry (CRG) 30mm A capacitor is not a perfect capacitance A low Equivalent Series Resistance (ESR) and a low Equivalent Series Inductance (ESL) are desirable IDCs and CRGs can provide lower ESL values

32. WelcomeConverter Chip EQ5382D from Enpirion 31.08.2009- 32 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Noise of edge strips: most sensitive noise indicator Black line: noise value without converter Thin black lines: statistical error of reference measurements Noise of edge strips: most sensitive noise indicator Black line: noise value without converter Thin black lines: statistical error of reference measurements Without converter L type PCB with toroid Toroid: d out = 18 mm, h = 3 mm, m = 0.8 g L = 0.6 µH, R = 0.3  35 µm aluminium Low DropOut Regulator IC that removes voltage ripples < 5mV by transforming them into heat

33. Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 33 -  The better result is always achieved with miniTors  The new AC2_classic PCBS are slightly better than the modified L type  IDCs (and CRGs) help to reduce the noise significantly AC2_IDC L type Different lengths of the AC2-boards are compensated with additional connector plugs Without converter miniTor tinyTor WelcomeModule Noise with the New PCBs L type, mod. AC2_classic

34. WelcomeButterworth Pi Filters Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 34 - C1=C2=22µF L1=2.5nF (R DC  ≤5m  ) f cut  1MHz C1=C2=2.2µF L1=2.5nF (R DC ≤ 5m  ) f cut  3MHz F2 A typical pi filter: The name derives from the form of the filter  usually 3 components Pi filters can be implemented in different ways The type of filter is given by the ratios of the filter components We went for the Butterworth filter  Gain decreases rather slow but shows no ripples The number of used components corresponds to the order of the filter Higher orders lead to steeper gains The order of a pi filter is 3  A Butterworth pi filter provides a gain of -60dB per freq. decade Two different cut off frequencies have been tested f g f g f g f g -3dB at f cut Chebyshev tpye 2 ButterworthChebyshev tpye 1 Elliptic F1

35. WelcomeEffect of LDO and Filter (2) Jan Sammet – RWTH Aachen – I. Physikalisches Institut B - 35 - Without converter AC2_classic (with tiny toroids) AC2_IDC (with tiny toroids)

36. Welcome Further Activities of our SLHC-Group 31.08.2009- 36 -Jan Sammet – RWTH Aachen – I. Physikalisches Institut B Electronics Cooling Cables Sensitive Support Like DC-DC conversion, evaporative CO2 based cooling is hoped to reduce the material budget in the order of 10% Power Develop converter PCBs and a powering scheme for SLHC phase II (already mentioned) Perform system tests with pixel modules  Provide DC-DC converters for the upgrade of the pixel tracker for phase I Power Develop converter PCBs and a powering scheme for SLHC phase II (already mentioned) Perform system tests with pixel modules  Provide DC-DC converters for the upgrade of the pixel tracker for phase I Cooling Module and super-module thermal design Design and optimization of thermal interfaces Evaluation of new materials Design, construction and commissioning of a re-circulating CO2 cooling test system Gain confidence in evaporative CO2 cooling Cooling Module and super-module thermal design Design and optimization of thermal interfaces Evaluation of new materials Design, construction and commissioning of a re-circulating CO2 cooling test system Gain confidence in evaporative CO2 cooling