Xenon Detector Status Liquid Xenon Group

1 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

2 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

3 Honeycomb panel test completed 3 rd panel delivered to Pisa at 16:30 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

4 Inspection of the panel

5 Low temperature test Wrapped with insulators and cooled with LN2 Pressurized with compressed air –2 bar –No damage on the panel found

6 And mounted on the cryostat 400 micron carbon-fiber plate between the panel and window to fill the gap As of 13/Mar

7 Cold and Warm Vessel Assembly As of 19/April

8 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 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 12:00. –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 -6 mbarl/sec N2 1.0 bar He 0.6 bar  7.8x10 -6 mbarl/sec N2 1.0 bar He 0.8 bar  2.2x10 -5 mbarl/sec The leak was not fixed at SIMIC by any means. We decided to bring the cryostat to PSI and perform a leak test

9 Cryostat arrived at PSI Delivery at 7:00 am on 5/June Works to be done Cleaning Leak/pressure test Alignment –PMT installation –…

10 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

11 Leak Test at PSI Finally we found a hole on the welding line of the thin window!

12 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 < 3x10 -9 mbarl/sec

13 Alignment at PiE5 Decide the cryostat position on the platform. Check how we can install the cryostat in the electronics hut

14 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

15 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

16 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)

17 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

18