Xenon Detector Status

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Xenon Detector Status

• Liquid Xenon Group

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Outline

• Cryostat construction
• Honeycomb panel test at Pisa
• Assembly
• Cryogenic test at SIMIC
• Leak test at PSI
• Detector preparation at PSI
• Alignment at PiE5
• PMT installation
• Schedule

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Cryostat delivery to PSI

• Delivery to PSI on 5/June
• 6 weeks delay from the schedule reported in the
  previous review meeting
• Delay of construction
• not due to a technical problem
• Delay of the cryogenic test at SIMIC
• Difficulty to stop leak

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Honeycomb panel test completed

• 3rd panel delivered to Pisa at 1630 on 20/Feb
• Mounted on the text box and tested on 22, 23/Feb
• 3 bar
• Inspection by a Plyform expert
• 4 bar x4 times
• Hold for 3 minutes at 4 bar in the last test
• Panel deformation (max)
• 0.3 mm at 1 bar
• 3.4 mm at 4 bar

Holes for evacuation
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Inspection of the panel
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Low temperature test

• Wrapped with insulators and cooled with LN2
• Pressurized with compressed air
• 2 bar
• No damage on the panel found

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And mounted on the cryostat

• 400 micron carbon-fiber plate between the panel
  and window to fill the gap

As of 13/Mar
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Cold and Warm Vessel Assembly
As of 19/April
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Cryogenic Test at SIMIC

• -18/May
• All nuts on the covers of the cold vessel were
  fastened tightly and the warm vessel was
  evacuated whole weekend.
• 21/May
• He leak test. 1.8Bar He was filled and found that
  the leak rate was larger than 10-4 mbarl/sec.
  Keep evacuation during the night.
• 22/May
• cooling using cold gas from the LN2 tank. Cold
  gas in the cold vessel Most parts were cooled
  down to -5-10 degree C.
• 23/May
• liquid N2 through the cooling pipe. All parts
  cooled below -110 degreeC around 1200.
• Then N2 gas at 1.0Bar and He gas filled step by
  step with measuring leak rate.
• N2 1.0 bar He 0.2 bar ? 5x10-7 mbarl/sec
• N2 1.0 bar He 0.4 bar ? 1.6x10-6mbarl/sec
• N2 1.0 bar He 0.6 bar ? 7.8x10-6mbarl/sec
• N2 1.0 bar He 0.8 bar ? 2.2x10-5mbarl/sec
• The leak was not fixed at SIMIC by any means.
• We decided to bring the cryostat to PSI and
  perform a leak test

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Cryostat arrived at PSI

• Delivery at 700 am on 5/June
• Works to be done
• Cleaning
• Leak/pressure test
• Alignment
• PMT installation

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Leak and Pressure Test at PSI

• The metal gasket was not compressed correctly due
  to deformed shape of the flange
• Re-machining the flanges by hand
• Supporting structure installed to evacuate the
  inner vessel for the leak test

cover
flange
gasket
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Leak Test at PSI

• Finally we found a hole on the welding line of
  the thin window!

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Leak test again

• After closing the hole, we performed a leak test
  again (with recycling the metal gaskets and with
  viton O-rings)
• Cracks found at corners
• Eddy-current measurement
• US-bottom d1.3mm L7mm, -top OK
• DS-bottom d0.8mm L13mm, -top d0.8mm L5mm
• It was confirmed that these did not cause leak.
• In the end we confirmed the tightness of the
  cryostat by using viton O-rings.
• Leak rate lt 3x10-9 mbarl/sec

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Alignment at PiE5

• Decide the cryostat position on the platform.
• Check how we can install the cryostat in the
  electronics hut

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Alignment at PiE5

• Alignment of the cryostat
• PMT support is aligned relative to the beam line
  within an accuracy of 1mm
• Cryostat leg positions determined on the platform
• Screw holes to fix the legs
• G10 insulator between the platform and legs

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Piping and cabling

• Working in a clean hut
• Cabling from patchpanels to feedthru almost
  finished
• LN2, GXe, LXe piping is ongoing in parallel to
  PMT installation

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PMT installation

• Patchpanel Feedthru cabring completed
• PMT installation started on 8/July
• Outer and Top PMT installation completed on
  9/July
• Now working on the inner (as of 12/July)

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Schedule

• PMT installation, -19/July
• PMT test at room temperature, 20-23/July
• He leak test, 25-28/July
• Ready to move to PiE5 on 30/July
• Evacuation and liquefaction in August
• 950 liter xenon is already liquefied
• Alpha/cosmic runs at the end of August
• In parallel to purification
• Monitor xenon purity

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