1 / 25

Novel Powering Schemes for the CMS Tracker Upgrade - R&D at RWTH Aachen University

Novel Powering Schemes for the CMS Tracker Upgrade - R&D at RWTH Aachen University. Meeting of the Joint Atlas/CMS Powering WG 7th of April, 2008. Lutz Feld, Rüdiger Jussen, Waclaw Karpinski, Katja Klein , Jennifer Merz, Jan Sammet 1. Physikalisches Institut B, RWTH Aachen University.

claus
Download Presentation

Novel Powering Schemes for the CMS Tracker Upgrade - R&D at RWTH Aachen University

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Novel Powering Schemes for the CMS Tracker Upgrade - R&D at RWTH Aachen University Meeting of the Joint Atlas/CMS Powering WG 7th of April, 2008 Lutz Feld, Rüdiger Jussen, Waclaw Karpinski, Katja Klein, Jennifer Merz, Jan Sammet 1. Physikalisches Institut B, RWTH Aachen University

  2. Outline • The current CMS tracker and its powering scheme • Plans for R&D at RWTH Aachen University • System test with commercial DC-DC converters • The converter • Setup and methodology • First preliminary results • Summary & Outlook CMS tracker R&D on novel powering schemes at RWTH Aachen University

  3. The Current CMS Tracker  Pure silicon tracker: 1m2 pixel area + 200m2 strip area  15 148 silicon strip modules, 29 different types  10 Million Strips, 84 Million pixels  Operating temperature < -10 C 5.8 m 2.5 m CMS tracker R&D on novel powering schemes at RWTH Aachen University

  4. The Current CMS Tracker Frontend-Hybrid with - 4 or 6 APV25 readout chips - PLL chip for timing - Multiplexer chip (MUX) - DCU chip for control Typical strip module APV25 readout chip: - 0.25 m CMOS - 128 strips per APV - analogue readout - per channel: pre-amplifier, CR-RC shaper, 4 s pipeline -  = 50ns • Supply voltages: 1.25V & 2.5V for analogue readout and 2.5V for digital control ring • Currents per APV: 0.118A at 2.5V and 0.061A at 1.25V • Power consumption of 4 (6) APV module including optical conversion: 1.8W (2.7W) CMS tracker R&D on novel powering schemes at RWTH Aachen University

  5. Powering the Current CMS Tracker • Several modules (typically 8) are powered in parallel • Custom CAEN power supply system (EASY 4000) - A3486 AC/DC converter provides 48VDC - A4601/4602 provide 2.5V, 1.25V & bias voltage • Copper low impedance cables from racks to patch panel just outside of tracker volume ( 50m) • Aluminium or copper multiservice cables from patch panel to tracker structures (few metres) Patch panel • Total strip tracker FE power consumption: 33kW • Total power supplied to strip tracker: 68kW •   34kW = 50% is lost in the cables • Inside cold volume,  36% is lost in the cables CMS tracker R&D on novel powering schemes at RWTH Aachen University

  6. CMS Tracker R&D for SLHC • Significant R&D effort started slowly due to ongoing work for current tracker • Strawman tracker designs are being worked out • Main focus of current R&D on simulation of strawmen • A new big challenge: integration of tracker into Level1 trigger • Re-design of readout chip has not yet started  future chip parameters not known all system tests on powering schemes still have to be done with APV25 • Boundary conditions for powering to be understood - must current cables be re-used? • Serious thinking on powering schemes has started about half a year ago; no prejudice for serial powering or DC-DC conversion • Tracker power working group is being set up CMS tracker R&D on novel powering schemes at RWTH Aachen University

  7. Working Group at RWTH Aachen University • Lutz Feld: team leader • Waclaw Karpinski (+ workshop team): electronics engineer • Katja Klein: HGF Fellow (4 years) • Three diploma students: • Jan Sammet: System test measurements with DC-DC converters • Rüdiger Jussen: Development and test of radiation hard magnetic field tolerant DC-DC converter (in collaboration with CERN PH-ESE group, see later) • Jennifer Merz: Simulation of material budget of various powering schemes CMS tracker R&D on novel powering schemes at RWTH Aachen University

  8. Plans for R&D at Aachen • No prejudice wrt serial powering and DC-DC conversion investigate and learn about both schemes before decision can be taken • DC-DC conversion started • Contributions to the development of a rad. hard, magnetic field tolerant buck converter (development of PCB), in coll. with CERN PH-ESE (F. Faccio et al.) • Characterization of this custom converter: magnetic field test, irradiation tests • Integration into and system test with current & future tracker structures • Preparation of setups & first system tests with of-the-shelf converter ongoing • In the longer term: study of general system issues • 1-step or 2-step conversion? • Converter on chip/hybrid/PCB? • Interplay with new readout chip etc. • Serial powering not started yet • Integration of serial powering scheme into current/future tracker system • System performance test • R&D proposal submitted and approved (Dec.) within CMS CMS tracker R&D on novel powering schemes at RWTH Aachen University

  9. A Commercial DC-DC Converter Custom rad. hard converter under development, delivery expected for summer start with a commercial of-the-shelf converter to prepare setups, to learn about system behaviour and to gain experience Market survey (W. Karpinski) with main criteria: - high switching frequency  small size of passive components - high conversion factor - sufficient current (~ 1A) & suitable output voltages (1.25V and 2.5V)  Enpirion EN5312QI (studied) and Micrel MIC3385 (delivered recently) • Characteristics of EN5312QI: • Small footprint: 5mm x 4mm x 1.1mm • fs 4 MHz • Vin = 2.4V – 5.5V (rec.) / 7.0V (max.) • Iout = 1A • Integrated planar inductor with iron-manganese-zinc core CMS tracker R&D on novel powering schemes at RWTH Aachen University

  10. Integration into CMS End Cap System • 4-layer adapter PCB • Plugged between Tracker End Cap (TEC) motherboard and FE-hybrid • 2 converters provide 1.25V and 2.5V for FE-hybrid • Input and output filter capacitors on-board • Input power external or via TEC motherboard CMS tracker R&D on novel powering schemes at RWTH Aachen University

  11. Integration into CMS End Cap System L-type: Larger flat PCB,1 piece TEC motherboard („InterConnect Board“, ICB) Front-end hybrid S-type: Smaller inclined PCB, 2 pieces CMS tracker R&D on novel powering schemes at RWTH Aachen University

  12. EN5312QI: Inductor & Magnetic Field Tolerance X-ray, U = 35kV, 5 minutes • MEMS technology: spiral inductor betw. magnetic cores • Decrease of efficiency in magnetic field • Total breakdown for fields below 1T (no surprise) • Lower magnetic field tolerance for higher duty cycles D D = Ton / T = Vout / Vin • Tolerance depends on orientation of converter in field Vout = 1.25V Axial: Tangential: B-probe magnet (B < 1.2T) CMS tracker R&D on novel powering schemes at RWTH Aachen University

  13. EN5312QI: EMI Measurements • Standardized EMI test setup at CERN (details in talk by G. Blanchot) • Standalone test of converter noise (common & differential mode) • Different converters and PCB designs can be compared • Low noise emission of EN5312QI (only S type measured) • Duplication of setup in Aachen has started EMI Setup at CERN EMI receiver Common mode Differential mode Filters Load Current probe CMS tracker R&D on novel powering schemes at RWTH Aachen University

  14. System Test Setup • TEC “petal“ with InterConnect Board • Four ring-6 modules powered & read out • Petal housed in grounded metall box • Optical readout • Optical control communication • Thermally stabilized at +15°C • Final components (spares) • Official DAQ software 6.3 6.2 6.4 6.1 CMS tracker R&D on novel powering schemes at RWTH Aachen University

  15. Effect of Converter (Position 6.4) ---- No converter ---- L type ---- S type Pos. 6.4 Powered via ICB Preliminary Pos. 6.4 •  Raw noise increases by 5-10% • Design of PCB has significant impact • Further optimization seems possible Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

  16. Effect of Converter (Position 6.4) ---- No converter ---- L type ---- S type Pos. 6.4 Powered via ICB Preliminary Pos. 6.4  Broader common mode distribution Huge increase of noise at module edges, APV edges and “bad“ strips effect is not yet understood Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

  17. Effect of Converter (Different Positions) ---- No converter ---- L type ---- S type Pos. 6.2 Powered via ICB Preliminary (Comparison for position 6.1 not possible because L type does not fit) Pos. 6.3 Pos. 6.4 Preliminary Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

  18. Common Mode Subtraction ---- Raw noise without converter ---- Raw noise with converter ---- CM calculated per APV (128 strips) ---- CM calculated for 32 strips ---- Linear CM subtraction Pos. 6.4 L type L Type Powered externally Preliminary • Additional noise completely subtractable with proper common mode algorithm • Noise increase due to higher common mode CMS tracker R&D on novel powering schemes at RWTH Aachen University

  19. Cross Talk ---- No converter ---- Converter on all positions ---- Converter on 6.4 only Pos. 6.4 L type L Type Powered externally Preliminary Pos. 6.3 ---- No converter ---- Converter on 6.4 • Performance with converter does not depend on # of modules operated with converter • A converter on position 6.4 does not spoil the performance of modules without converter (e.g. 6.3) Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

  20. Cross Talk Study correlations between pairs of strips i, j (R = raw data): Corrij = (<RiRj> - <Ri><Rj>) / (ij) With converters on 6.3 and 6.4 Without converters Preliminary Preliminary Strip number Strip number Pos. 6.4 Correlation coefficient Correlation coefficient Pos. 6.3 Strip number Strip number • No cross-talk between neighbouring modules observed • High correlations only within single modules (common mode) CMS tracker R&D on novel powering schemes at RWTH Aachen University

  21. Noise versus Input Voltage Expectation for output voltage ripple Vout (with duty cycle D = Vout / Vin): Mean noise per module Pos. 6.4 L type Pos. 6.4 L type Preliminary Preliminary • Mean noise increases with input voltage or conversion ratio g (g = Vin / Vout) CMS tracker R&D on novel powering schemes at RWTH Aachen University

  22. Summary & Outlook • We have started to a programm to understand the issues related to operation of CMS tracker modules with DC-DC converters • First measurements with a commercial converter indicate an increase ofthe module noise due to a higher common mode by up to 10% • Increase of edge strip noise to be studied • Further optimization of adapter PCB seems possible • No indication for cross talk when powering with DC-DC converters • Many more interesting measurements are in the pipeline • Operation of a complete petal with Enpirion converters • Noise injection on silicon modules • Micrel converter with 8 MHz switching frequency • Integration of EN5312QI with external air coil • Combination of DC-DC converter with voltage regulator • Hope to start similar studies with custom converter (CERN) this summer CMS tracker R&D on novel powering schemes at RWTH Aachen University

  23. Back-up

  24. Different Methods of Powering ---- No converter ---- L/S type powered externally ---- L/S type powered via ICB;many filter capacitors Pos. 6.4 L type Preliminary Pos. 6.4 S type  Sensitivity to input voltage ripple to be strudied, but sensitivity seems to be small Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

  25. Effect of Output Filter Capacitance ---- No converter ---- Standard output filter capacitors ---- Additional 22 F capacitor ---- Additional 100 F capacitor Pos. 6.4 L type Powered externally Preliminary Pos. 6.4 S type  Noise can be reduced further by larger output filter capacitances Preliminary CMS tracker R&D on novel powering schemes at RWTH Aachen University

More Related