Brief Overview of BTeVPixel Detector System Simon Kwan Fermilab BTeV Mechanical, Cooling, and Vacuum System Design Internal Review, November 20, 2001
BTeV Pixel Vertex Detector • Reasons for Pixel Detector: • Superior signal to noise • Excellent spatial resolution -- 5-10 microns depending on angle, etc • Very Low occupancy • Very fast • Radiation hard • Special features: • Info used in Level 1 trigger • inside a dipole giving a crude standalone momentum • nominally at 6mm from beam • Retractable: move out during beam fill and then in for data taking • In vaccum; • rf shielding
Pixel Detector • Pixel Sensor bump-bonded to Readout chip • Fine segmentation • Large number of channels • Electronics in the active tracking volume • High power density • Material budget • Basic building block – Multichip Module (MCM) • Large amount of data • Large number of HDI and cables
Pixel System R&D Status • Detector components in rather good shape (readout chip, sensor, detector tests, HDI, module testing, readout electronics incl. Test-stand) • Benefit from others experiences • Recent effort focussed on the system aspects (mechanical support, cooling, vacuum system – this review) • High risks area – develop fallbacks • Pixel readout (now solved) • Bump bonding and sensor p-stop isolation (two technologies) • Substrate • Cooling
Pixel Mechanical System Design Challenges • Geometrical constraint (inside a magnet, close to IP etc) • Magnetic field effects • Close to IP but little impact on Tevatron operation • Vacuum (outgassing, feedthroughs, leak tight etc) • Retractable yet can be easily aligned and stable during operation • High Radiation environment • High power density and yet desired operating temp. of detector is –5 to –10 C and be kept stable • Lots of cables, connectors from vacuum to outside • Mechanically stable yet light weight, minimal material in a large volume, low CTE • Cooling: efficient, leak-tight, coolant has to be low density, low Z, low viscosity, stable, non-corrosive, inflammable, and non toxic
Pixel detector • 30 stations (substrates with embedded cooling channels) • Carbon support frame • Lots of cable and connectors • heat exchanger • Motor drive • Rf shield • Vacuum system • Vacuum vessel • Vacuum feedthroughs
Charge to the Committee • Assess the technical feasibility of the proposed design • Advise us on any design flaws, potential problems, and any items that may have been overlooked. • Address the following questions: • Is the design technically feasible and suitable to achieve the desired mechanical and cooling performance ? The review should consider the overall system and its individual components. • Are the proposed construction and assembly techniques viable? • Is the necessary R&D being done and will it yield a final product on the required time scale? • Are there mechanical properties of this design that can affect adversely the overall performance of the system (e.g. electrical integrity, noise immunity…)? • Have all the risks been identified and are there measured that have been considered to mitigate these risks? Where is it necessary to consider fallback plans and do we have viable strategies when required? • Which areas should we concentrate on for the next 6 months before the baseline review? • Are there any potential roadblocks on the way to achieve a reliable cost and schedule estimate before the baseline review?