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Xenon Detector. Xenon Detector Group. Contents. Cryostat Construction Detector Preparation Schedule. Cryostat Construction. Xenon Cryostat is NOT DELIVERED YET. Cryostat Construction Cold Vessel. Honeycomb Panel Construction. Thin Window Welding PMT Support Inst. Test - PowerPoint PPT Presentation


  • Xenon DetectorXenon Detector Group

  • Contents

    Cryostat Construction

    Detector Preparation


  • Cryostat ConstructionXenon Cryostat is NOT DELIVERED YETCryostatConstructionCold VesselHoneycomb Panel ConstructionThin Window WeldingPMT Support Inst. TestVacuum Leak TestPressure TestCryogenic TestPressure TestLow-Temp Test

  • Schedule Reported in the Last MeetingWeek 19-23 June:Warm vessel: Complete welding of all nozzle (3 days).Cold vessel: Complete welding of CF 100 flanges, braze the cooling tube (3 days) Welding test of the windows (2days)New foil fabrications (4 days).Define Honeycomb materials and geometry (2 days) delivery (15 days)Week 26-30 June:Test box preparation: warm window test box (1day); cold window test box (3days).Welding of warm window on the test box (2 days) + helium leak test (1day)+ mechanical test (1day).Machining of cold vessel (5 days).Week 3-7 July:Welding of cold window on the test box (2days)- helium lesk test (1day).New honeycomb delivered mechanical test cold window (1day).Welding window on cold vessel (2days)Week 10-14 July:Test warm vessel (2days).Helium test of cold window (1day)Honeycomb mounting and cold test preparation (1day)Pressure test cold vessel, 4 bar, (1day)

    Week 17-21 July:Dry out cold vessel (1day)- helium leak test of metallic sealing on covers (1day).Mounting of the phototube supporting structure (2days)Welding of the L bracket to hold the arches (phototube supporting structure) (1day)Installation of super insulation and temperature sensors (1day)Week 24 -28 July:Alignment and vessel integration (3days)Bellows welding (3day) Week 31July - 4 Agust:Helium leak test on the welds (1day)Internal polishing (3days)Cleaning and dryout (2days)Week 7- 12 August:Preparation and installation of equipmnets for the cryocenic test (1day)Cryogenic test (4days)Week 14- 18 August:Helium leak test of cold vessel (2days)Prepartation of shipmenet (2days)Week 21- 26 August:Delivery to PSI

    End OctEnd Dec

  • Why is Cryostat Construction Delayed?Thin window welding and related tests took longer time than expected, which is now successfully completed.

    PMT support did not fit the cold vessel wall because of deformation that had appeared during construction process.

  • PMT Support Installation TestCold vessel construction procedure

    Test was performed on 29/Sep/06, but Assemble and weldLeak testMachiningThin window weldingHoneycomb panelInstallation into the warm vesselIdealRealityXenon coming in.Several mm gapLXe R.L. 2.89 cmSupport structure cannot come in

  • Protocol UpdateDiscussion between SIMIC and INFNUpdate schedule including remachining of the cold vessel wallCheck points at milestone activitiesHe Leak Test, Pressure Test, etc.Assign another SIMIC engineer who can respect the schedule in a cautious mannerIn case of schedule slippage without any acceptable reason, we will stop SIMIC and continue at a different manufacturer.

  • Remachining of the Inner Vessel WallAviolamer (Pianezza, TORINO)6-axis milling machine3D Coordinate Measuring Machine


  • PMT Support Installation TestThe welded thin window was removed for this procedure

    Scraped away the inner wall by 5mm at maximum

    PMT support successfully installed

    Checked with a gap gauge of 200 mm with the supporting structure installed on 22/Jan/2007

  • Vacuum Leak Test with Metal GasketHe vacuum leak test of the cold vessel with Helicoflex sealing (metal gasket) at a sensibility of 10-9 cc atm/sec on 14/Dec/2006

    OK at the upstream side, but not OK at the downstream side because of

    Fixed by filling the hall with a metal piece, and tested again on 18/Dec/2006welding

  • Pressure TestTest up to 4 bar on 19/Dec

    Displacement measured at 4 different locations

    The test was repeated twice1st test OK2nd testWater leak at the upstream flange, which was later found to be due to scratch on the groove.

    This was fixed and checked in another vacuum leak test performed on 22/Dec/20064 Bar!

  • Comparison with SimulationDisplacement measured at 4 bar1.7 mmDial. N. 21.2mm1.25mm0.55mmModeling1.3 mmDial. N.1

  • Thin Window Welding AgainThe honeycomb panel and PMT structure are used to guarantee that there is no gaps between them. SIMIC is now drilling the blind thread holes to restrain the panel.Position of the blind holesThin Window WeldingPMT Holder Inst. TestVacuum Leak TestPressure TestCryogenic Test

  • Honeycomb Panel Production

  • Honeycomb Panel Brief RetrospectOK on this sideThe 1st panel broke down in pressure test as reported in the last meeting

    New (2nd) panel was designedHoneycomb thickness 19mm 26.5mmHigh module prepreg 0.75mm 1mmTransition with fabric only Taper Transition1st honeycomb panel pressure test1st panel2nd panel

  • Pressure Test of the 2nd PanelPressure test was stopped at 2.5 bar to check the panel internal surfaceSmall crack on the surface

    The panel was tested again with proper SIM between the panel and test boxCurvature of the panel OKCurvature of the test box NO

    Succeeded to apply up to 4 BarRepeated 4 timesBreak down at the end


  • The 3rd PanelInternal reinforcement at the edges.Fiber with lower module but with a better Elongation (T300, used in aerospace applications with over 20 year service history).1.5mm prepreg thickness with 8 piles (1mm in the 2nd panelSpace-approved Resin epoxy (Hysol EA9361)Internal reinforcementCoca-Cola can shape

  • Construction of the 3rd PanelThe 3rd panel requires more intermediated construction steps and a lot of preparation of parts prior to gluing and assemblyCentralhoneycombInternal reinforcementInternal skinExternal skin

    Forming the external skinForming the honeycombMachining the honeycombForming the external skinGluing the reinforcement to the central honeycomb in the primary moldGluing the external skin to the honeycomb using paste adhesiveGluing the internal skin to the rest parts with paste adhesive

    Two additional molds are necessary

  • Construction Status of the 3rd PanelDelivery to Pisa in this weekPressure and low temperature test soon after that before bringing to SIMIC on 21/FebOuter Skin

  • Updated Construction ScheduleShipping to PSICryogenic Test

  • Detector PreparationXenon StorageCables and Related ElectronicsNaI Detector for Pi0 CalibrationC-W Proton Acc Peters PresentationNickel 9 MeV Gamma Generator

  • Xenon Storage~900L in liquid, largest amount of LXe ever liquefied in the worldVery stablePressure raise 0.003MPa/h w/o cooling0.111 MPa 0.2 MPa in 44 hours

  • Cables and Related ElectronicsSignal and HV cables have been already laid down

    Signal Splitter and HV power supply are ready, too

    HV ControllerGUI for Xe HV controlRuns in monitor mode of meganalyzer2D PMT map with markersSome more functionsWill be tested soon with real HV modules

  • NaI Detector for Pi0 Calibration9 NaI (Tl) Crystals, 62.5x62.5x305mmEach viewed by 2 APDs (5mm x 5mm)Electronics Test with MEG DAQ (DRS) at PiE5Cosmic-Ray dataNeed to improve S/N

    APD with larger active are2 x 5mm x 5mm 10mm x 10mm

    COMIC DRS Data

  • Neutron BG MeasurementMultiple locations with different detectors (PiE5 in Dec/2006)Bonner SphereNaI activation method with Cd foil wrappingTotal flux 3.7 n /sec/cm2, Thermal flux 0.5n /sec/cm2Small enough for Xe Detector PMT operationm beam4 x 4 cylinder;activation techniquethermal and non-thermal separattion by using Cd-wrapping method Precise measurement of thermal neutron flux and estimate of non thermal neutron flux. 3He counter2, 3, 5, 8, 10, 12 spheres Neutron energy spectrum determination: sphere response functionsnumerical unfolding codes.New

  • LEDPMT GainHigher V with light att.Can be repeated frequently alphaPMT QE & Att. LCold GXe LXeLaser(rough) relative timing calib.< 2~3 nsecNickel g Generator9 MeV Nickel -lineNaIPolyethylene0.25 cm Nickel platequelleonoffIlluminate Xe from the backSource (Cf) transferred by comp air on/offProton AccLi(p,)BeLiF target at COBRA center17.6MeV g~daily calib.Can be used also for initial setup KBiTlFLi(p, 0) at 17.6 MeVLi(p, 1) at 14.6 MeVm radiative decayp0 ggp- + p p0 + n p0 gg (55MeV, 83MeV)p- + p g + n (129MeV)10 days to scan all volume precisely(faster scan possible with less points)LH2 targetge+e-egnmnLower beam intensity < 107Is necessary to reduce pile-upsBetter st, makes it possible to take data with higher beam intensity A few days ~ 1 week to get enough statisticsXenonCalibrationNew

  • ScheduleAvailable online athttp://meg.web.psi.ch/subprojects/install/xenon.html

    After the detector is ready,PMT HV adjust, gain calibration, and a-source (and Cosmic-Ray) data acquisition (2 Weeks) Proton Acc DAQ (2 Weeks)p0 run (3 Weeks, 10 Days full DAQ)Radiative m decay run with lower beam intensity (2 Weeks)AprilCryostat delivery to PSI Alignment at PiE5Start of PMT installationMayComplete PMT installationCheck electrical connectionStart evacuationJunePre-coolingLiquefaction PurificationLiquefaction (liquid transfer) will end on 17/June

  • SummaryCryostat constructionMany problems occurred, but they are getting solved one by oneHoneycomb panel will be delivered to Pisa in this week and tested before bringing it to SIMICCryostat delivery to PSI in April after a cryogenic test

    Detector preparation is in good conditionCalibration procedurespi0C-W AccNickel g Neutron measurement performed againBG level is expected to be small enough for the xenon detector operation


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