1. Xenon Detector Xenon Detector Group

2. 1 Contents Cryostat Construction Detector Preparation Schedule

3. 2 Cryostat Construction Xenon Cryostat is NOT DELIVERED YET Cryostat Construction Cold Vessel Honeycomb Panel Construction Thin Window Welding PMT Support Inst. Test Vacuum Leak Test Pressure Test Cryogenic Test Pressure Test Low-Temp Test

4. 3 Schedule Reported in the Last Meeting Week 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 Oct End Dec

5. 4 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.

6. 5 PMT Support Installation Test Cold vessel construction procedure Test was performed on 29/Sep/06, but … Assemble and weld Leak test Machining Thin window welding Honeycomb panel Installation into the warm vessel Ideal Reality Xenon coming in. Several mm gap LXe R.L. 2.89 cm Support structure cannot come in ~6mm

7. 6 Protocol Update Discussion between SIMIC and INFN –Update schedule including remachining of the cold vessel wall –Check points at milestone activities He Leak Test, Pressure Test, etc. –Assign another SIMIC engineer who can respect the schedule in a cautious manner –In case of schedule slippage without any acceptable reason, we will stop SIMIC and continue at a different manufacturer.

8. 7 Remachining of the Inner Vessel Wall Aviolamer (Pianezza, TORINO) –6-axis milling machine –3D Coordinate Measuring Machine 632.1 631.6 632.0 634.5 635.9

9. 8 PMT Support Installation Test The 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  m with the supporting structure installed on 22/Jan/2007

10. 9 Vacuum Leak Test with Metal Gasket He 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/2006 welding

11. 10 Pressure Test Test up to 4 bar on 19/Dec Displacement measured at 4 different locations The test was repeated twice –1 st test OK –2 nd test Water 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/2006 4 Bar!

12. 11 Comparison with Simulation Displacement measured at 4 bar 1.7 mm Dial. N. 2 1 2 3 4 1.2mm 1.25mm 0.55mm Modeling 1.3 mm Dial. N.1

13. 12 Thin Window Welding Again The 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 holes Thin Window Welding PMT Holder Inst. Test Vacuum Leak Test Pressure Test Cryogenic Test

14. Honeycomb Panel Production

15. 14 Honeycomb Panel – Brief Retrospect OK on this side The 1 st panel broke down in pressure test as reported in the last meeting New (2 nd ) panel was designed –Honeycomb thickness 19mm  26.5mm –High module prepreg 0.75mm  1mm –Transition with fabric only  Taper Transition Thin window welded on the cold vessel Honeycomb panel 1 st honeycomb panel pressure test 1 st panel 2 nd panel

16. 15 Pressure Test of the 2 nd Panel Pressure test was stopped at 2.5 bar to check the panel internal surface –Small crack on the surface The panel was tested again with proper SIM between the panel and test box –Curvature of the panel OK –Curvature of the test box NO Succeeded to apply up to 4 Bar –Repeated 4 times –Break down at the end Pressure SIM

17. 16 The 3 rd Panel Internal 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 2 nd panel Space-approved Resin epoxy (Hysol EA9361) Internal reinforcement Coca-Cola can “Coca-Cola can” shape

18. 17 Construction of the 3 rd Panel The 3 rd panel requires more intermediated construction steps and a lot of preparation of parts prior to gluing and assembly Central honeycomb Internal reinforcement Internal skin External skin 1.Forming the external skin 2.Forming the honeycomb 3.Machining the honeycomb 4.Forming the external skin 5.Gluing the reinforcement to the central honeycomb in the primary mold 6.Gluing the external skin to the honeycomb using paste adhesive 7.Gluing the internal skin to the rest parts with paste adhesive Two additional molds are necessary 1.Forming the external skin 2.Forming the honeycomb 3.Machining the honeycomb 4.Forming the external skin 5.Gluing the reinforcement to the central honeycomb in the primary mold 6.Gluing the external skin to the honeycomb using paste adhesive 7.Gluing the internal skin to the rest parts with paste adhesive Two additional molds are necessary

19. 18 Construction Status of the 3 rd Panel Delivery to Pisa in this week Pressure and low temperature test soon after that before bringing to SIMIC on 21/Feb Rohacell Z reinforcement Honeycomb glued to the Z reinforcement and rohacell Inner skin Outer Skin

20. 19 Updated Construction Schedule Shipping to PSI Cryogenic Test

21. Detector Preparation Xenon Storage Cables and Related Electronics NaI Detector for Pi0 Calibration C-W Proton Acc  Peter’s Presentation Nickel 9 MeV Gamma Generator

22. 21 Xenon Storage ~900L in liquid, largest amount of LXe ever liquefied in the world Very stable –Pressure raise 0.003MPa/h w/o cooling –0.111 MPa  0.2 MPa in 44 hours

23. 22 Cables and Related Electronics Signal and HV cables have been already laid down Signal Splitter and HV power supply are ready, too HV Controller –GUI for Xe HV control –Runs in monitor mode of meganalyzer –2D PMT map with markers –Some more functions –Will be tested soon with real HV modules

24. 23 NaI Detector for Pi0 Calibration 9 NaI (Tl) Crystals, 62.5x62.5x305mm Each viewed by 2 APDs (5mm x 5mm) Electronics Test with MEG DAQ (DRS) at PiE5 –Cosmic-Ray data –Need to improve S/N APD with larger active are 2 x 5mm x 5mm  10mm x 10mm 60 o COMIC DRS Data

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27. 26 Neutron BG Measurement Multiple locations with different detectors (PiE5 in Dec/2006) –Bonner Sphere –NaI activation method with Cd foil wrapping –Total flux 3.7 n /sec/cm 2, Thermal flux 0.5n /sec/cm 2 –Small enough for Xe Detector PMT operation A C B  beam 4” x 4” cylinder;4” x 4” cylinder; activation techniqueactivation technique thermal and non-thermal separattion by using Cd-wrapping methodthermal and non-thermal separattion by using Cd-wrapping method Precise measurement of thermal neutron flux and estimate of non thermal neutron flux. Precise measurement of thermal neutron flux and estimate of non thermal neutron flux. 3 He counter 3 He counter 2”, 3”, 5”, 8”, 10”, 12”2”, 3”, 5”, 8”, 10”, 12” spheres Neutron energy spectrum determination: Neutron energy spectrum determination: sphere response functionssphere response functions numerical unfolding codes.numerical unfolding codes. New

28. 27 LED PMT Gain Higher V with light att. Can be repeated frequently alpha PMT QE & Att. L Cold GXe LXe Laser (rough) relative timing calib. < 2~3 nsec Nickel  Generator 9 MeV Nickel γ-line NaI Polyethylene 0.25 cm Nickel plate 3 cm 20 cm quelle on off Illuminate Xe from the back Source (Cf) transferred by comp air  on/off Proton Acc Li(p,  )Be LiF target at COBRA center 17.6MeV  ~daily calib. Can be used also for initial setup  K Bi Tl F Li(p,  0) at 17.6 MeV Li(p,  1) at 14.6 MeV  radiative decay  0    - + p   0 + n  0   (55MeV, 83MeV)  - + p   + n (129MeV) 10 days to scan all volume precisely (faster scan possible with less points) LH 2 target  e+e+ e-e- e e     Lower beam intensity < 10 7 Is necessary to reduce pile- ups Better  t, makes it possible to take data with higher beam intensity A few days ~ 1 week to get enough statistics Xenon Calibration New

29. 28 After the detector is ready, 1.PMT HV adjust, gain calibration, and  -source (and Cosmic-Ray) data acquisition (2 Weeks) 2. Proton Acc DAQ (2 Weeks)  0 run (3 Weeks, 10 Days full DAQ) 4.Radiative  decay run with lower beam intensity (2 Weeks) After the detector is ready, 1.PMT HV adjust, gain calibration, and  -source (and Cosmic-Ray) data acquisition (2 Weeks) 2. Proton Acc DAQ (2 Weeks)  0 run (3 Weeks, 10 Days full DAQ) 4.Radiative  decay run with lower beam intensity (2 Weeks) Schedule Available online at –http://meg.web.psi.ch/subprojects/install/xenon.htmlhttp://meg.web.psi.ch/subprojects/install/xenon.html April Cryostat delivery to PSI Alignment at PiE5 Start of PMT installation May Complete PMT installation Check electrical connection Start evacuation June Pre-cooling Liquefaction Purification Liquefaction (liquid transfer) will end on 17/June April Cryostat delivery to PSI Alignment at PiE5 Start of PMT installation May Complete PMT installation Check electrical connection Start evacuation June Pre-cooling Liquefaction Purification Liquefaction (liquid transfer) will end on 17/June 17/June End of Liquefaction

30. 29 Summary Cryostat construction –Many problems occurred, but they are getting solved one by one –Honeycomb panel will be delivered to Pisa in this week and tested before bringing it to SIMIC –Cryostat delivery to PSI in April after a cryogenic test Detector preparation is in good condition –Calibration procedures pi0 C-W Acc Nickel  –Neutron measurement performed again BG level is expected to be small enough for the xenon detector operation