FVTX Mechanical Status:Walter Sondheim - LANL Mechanical Project Engineer; VTX & FVTX

Mechanical Design Philosophy:The Design of the FVTX structures and services have been driven by the following requirements;High mechanical and thermal stability. Radiation tolerance up to an integrated dose over 10 years of 300 500 krads in the region of the detectors and 200 krads in the region of the ROC (read-out-card).High transparency to particles, keep the radiation length to a minimum, especially the material mass that is in the acceptance.Silicon modules to be maintained at room temperature or slightly lower, sensor electronics has low susceptibility to radiation damage.Very low maintenance over 10 year expected lifetime.High granularity of the services to increase the reliability of the operation.Modular Assembly.

VTX-FVTX Half Assembly for Introduction:Two half FVTX detectorsBeryllium beam-pipe, 41.021 mm OD X 800.0 mm longVTX detector, 4 layers; inner 2 pixels, outer two strip-pixel sensorsBig Wheel region; read-out electronics for VTX&FVTXSupport structure and isolation mounts attached to central magnet

Sensor Module: Two variations for stations2 & 3, upstream and downstream:UpstreamDownstreamPOCO graphite support block with pin hole for alignment, screw hole for mountingPEEK support block with pin hole for alignment and screw hole for mountingGraphite back-plane 1.56 mm, K13C2U carbon fiber, Cyanate Ester resin, fabrication at LBNLHDI .44 mmSensor .32 mmFPHX chips bonded to HDIMounting screw locationMounting screw locationHDI connectors to extension cable to ROCBonding of FPHX chips to HDI use Arclad 8026 transfer adhesive, 1 milBonding of silicon sensor to carbon backplane Arclad 8026 and Tra-bond 2902 silver epoxy

Half-Station sub-assembly, stations 2, 3 or 4:Mounting and alignment pins in tabs, 3 per station half diskThermally conductive block to transfer heat from wedge to support panelNylon mounting screw (phillips head)Graphite faced support panelFour layers of 15 degree wedges, 2 layers on each side of support panelEach wedge staggered in Z, 15 degrees between wedges on one side, upstream to downstream sides of panel offset by 7.5 degrees hermetic in phi. Each silicon sensor covers 7.5 degrees in phi.

Support Panel Construction:Hose barb PEEKInsert for screws and pins - PEEKWedge locating pinMounting tabGFRP face sheet, .25 mmCore foam, 4.76 mmCore insert, pins and screws, PEEKCooling channel, PEEKGFRP face sheet, .25 mmFabrication of disk assembly will take place at LBNL composite shopHoles for survey flag along edge

Half Cage Assembly with Liquid Cooling Circuit:Each station is cooled in parallel with the other stations.Inlet temperature 0 10 degrees C, delivery pressure 5 psiDelta-T per station 1.8 degrees C, delta p .4 psiCoolant 3M Novec 7200InletsOutletsNovec 7200:Boiling point 76 degree CMelting point -138 degree CVapor pressure 109 mmHg @ 25 degrees CNeutron irradiation study at LANLs WNR facility total dose 6.7 X 10**11 n/cm**2, nominal energy 800 Mev. Samples were sent to 3M for analysis of free Flouride, no indication of significant degredation.

FVTX Cage:Cage design uses CN60 carbon fabric with a EX1515 resin. FEA analysis indicates very rigid structure < 25. microns.Blocks and flanges POCO graphite ACF-100Q.Note: the mounting blocks for the 4 stations will be clocked in 1 degree increments.Each FVTX interfaces directly with the VTX space-frame.For scale: 400. mm in diameter, 187. mm in length.Penetrations in shell for survey/alignment flagsFabrication will take place at LBNL composite shop.

Coolant to FPHX Chips Thermal Path 2007 review current changes:Use Simple Correlations to EvaluatePressure dropsTemperature drop from fluid to cooling tubeApproximate temperatures with 10C coolant flowing at Re~10,000(0.76mm K13CU backplane, 50m Nickel tube, 0.2 W/mK epoxy, 0.75 W/mK silicone)2008 Changes to Wedge:FPHX readout chip power increased 100 to 600 micro-watts per chip.Rerun thermal model and FEA analysis over next month

Thicker 2XThicker 2.5XChannelPOCO graphiteArclad 8026 transfer adhesiveFoamPEEK

Large Station and Cage-Level Modeling:Fundamental Vibration ModeDistortion due to Cooling(assembled at room temperature)Max deflection ~ 21mMax deflection within active area ~ 8m138Hz

Measurement of Central magnet vibration;Vibration Level Threshold 1*E-8 g2/HzAccelerometer Noise Floor 1*E-11 g2/HzPeak Measured Vibration 1.2*E-9 g2/Hz Vibration measurements were made on the Central magnet pole tips to see if mounting the VTX-FVTX vertex detectors off the pole tips would induce unwanted vibrations to the operation of this detector system. A comparison of the vibration levels measured and the threshold levels calculated showed that the peak vibration levels are 10X lower than the threshold value. The measurements made in the PHEINX IR were successful at collecting sufficient data to conclude that the vibration levels on the support rails would not adversely affect the performance of the vertex detector system.

Two Independent Halves:Big Wheel cooling plate with coolant channel along perimeter, 3. mm AluminumROC cards, 38. watts/cardGas seal between layersWedge readout extension cables

This half FVTX assembly is stand alone, can be tested independently of the rest of the detector in a lab.

Model heat transfer in lab:Model heat transfer in wedge assemblyModel heat transfer from ROC cards to cooling plateWatlow heater 75 watt

Summary: WBS 1.6 Mechanics Schedule Dates & ManpowerWBS 1.610/21/2005 9/29/2009WBS 1.6.1 Specifications 10/21/2005 2/9/2006WBS 1.6.2 Support Structure Cage 4/1/2007 12/25/2009WBS 1.6.3 Wedge Backplane4/11/2008 6/19/2009WBS 1.6.4 Support Disk 1/4/2007 8/28/2009 WBS 1.6.5 Alignment and Assembly 8/1/2008 3/5/2009 Manpower1 engineers1 physicist liaisonHYTEC:1 Engineer1 Designer