Liquid Xenon Detector Group 1162020 Contents Cryostat Construction

Liquid Xenon Detector Group 11/6/2020

Contents • • Cryostat Construction PMT Cryogenic/Gas System (Calibration Carlo’s presentation) Liquid H 2 Target and Na. I Detector Slow Control Measurements of UV Light Reflection on Al and PEEK • Schedule 11/6/2020 1

Cryostat Vessels Windows Status & Schedule 11/6/2020

Cryostat Construction • • The main construction activities: – – – The main flanges are assembled, welded and pre-machined. All parts of the vessels are prepared and assembled. The cold and warm vessel are leak tested using provisory covers. – The two vessels are machined, providing the necessary apertures. – – – The windows are welded on the body. Leak and pressure tests are performed. The phototube support structure is installed and adjusted. The attachments to fix the structure are welded on the cold vessel. Temperature sensors and heaters are installed. – – – The two vessels are assembled together. The connection between them are done. Bellows are welded. A leak test of those weld is done. A cryogenic test is performed. Another leak test after the cryogenic test is repeated. The windows construction are done in parallel: 11/6/2020 – – Prepare frames, steel sheet, honeycomb panel, and test box. Welding of the parts. Leak test of the welding Installing the honeycomb panel – – Pressure test with instrumentation is repeated. Leak test after the pressure test. – The window are installed on the chamber. } Step 1 } Step 2 } Step 3 } Step 4 } Step 1 } Step 2 } Step 3 3

Construction Procedure Assemble and weld Machining Leak test Warm Assemble and weld Pressure & Leak test Assemble two vessels Weld Chimneys Install Windows Assemble and weld Machining Leak & Cryogenic tests Install sensor, PMT support attachment, etc. Leak test Cold Assemble and weld Step 1 11/6/2020 Pressure & Leak test Step 2 Step 3 Step 4 4

Warm/Cold Vessels 11/6/2020 Dec/ 2005 Feb/ 2006 Apr/ 2006 5

Leak Test before Machining • • The cold and warm vessels were leak tested using provisory covers. Cold vessel test 28 -29 -April-2006, Warm vessel 8 -May-2006 – Some problems were found in the cold vessel • Excessive deformation were found during the test. – The provisory covers were only touching the flanges. Sealing plaster was used to make them vacuum tight. • An internal structure were added to control the deformation of the cold vessel. No Cover 1 Bar Pressure Outer Vessel provisory Covers • Finite Element Analysis • Excessive deformation of the inner flange. • The real covers maintain the shape. • However we have a concern on the integrity of cold sealing, whether a local slip can occur between the cover and flange. 11/6/2020 OK With Cover 1 Bar Pressure 6

Machining • Cold Vessel 1 3 – Cu cooling pipe will be welded on the back 2 • Warm Vessel 11/6/2020 Middle of June 4 7

Bellows/Chimneys • Pressure Test OK • Up to Dp=4 Bar 11/6/2020 8

Windows • • A thin foil is welded to a 5 mm thick intermediate frame. Backing with a honeycomb/carbon fiber panel for the cold window. Cold Window Honeycomb/CF panel Intermediate frame Honeycomb/CF panel Weld Cross section A-A’ CF Al honeycomb 0. 4 mmt window Intermediate 5 mm frame Intermediate 5 mm frame weld Weld 11/6/2020 Intermediate 5 mm frame 9

Window Test Preparation • • A 5 mm intermediate frame was welded to the test box. After that the frame is cut out and welded to the vessel. • Preparation of test box. 14 -May-2006 Cold Window Warm window test box Warm Window Pressure Cold window test box 11/6/2020 Honeycomb/CF panel Leak test 10

Warm Window Test • One warm window was tested: – Mechanically it was O. K. – However during the test leak was found • SIMIC realized that their construction proposal for windows was not feasible. They took three days to weld the foil to the 5 mm intermediate frame and 10 days to find leaks. After that the window was leaking during the test. 11/6/2020 11

Cold Window Test • One cold window was tested: – Mechanically it was NOT O. K. Next slide – The welds were leaking. – SIMIC tried to repair the TIG weld using a brazing material, causing a disaster on the intermediate frame. 11/6/2020 12

Honeycomb/Carbon Fiber Panel Trouble • Mechanically the honeycomb/CF panel was NOT O. K. at Dp=3. 7 bar. (Design value of the cryostat pressure tolerance is 3. 0 Bar) • The honeycomb/CF panel broke at one side. – FEA with sophisticated laminated elements OK – This buckling is attributed to local defects. Carbon Fiber Transition area Al honeycomb OK on this side 11/6/2020 13

New Design of the Windows • New design proposed by SIMIC • The windows are welded directly on the bodies. – A leak test is performed on this weld on the body. – This design implies modification of the honeycomb… weld Honeycomb/CF panel Cold Vessel Warm Vessel Cold Vessel Weld Warm Vessel 11/6/2020 Turn up the edges and weld along them 14

New Honeycomb/CF Panel Design How can we solve the problem on the Honeycomb/CF panel? Change the material to avoid transition from the high modulus fiber to low modulus fiber around the edge and replace the filler material. • Previous design • – 5 plies of fiber sheets on each side of the panel • +45/-45/0/-45/+45 • Total thickness of 0. 7 mm. – Around the edge we use low modulus fiber sheets to make the bend (inter laminar method) and a filler material of epoxy with glass micro spheres (beads) inside. – The honeycomb thickness is 19 mm and the density is 50 kg/m 3. New design – 8 piles of fibers • Total thickness of 1. 0 mm – A thicker honeycomb 24 mm with the same density (50 kg/m 3) to increase the inertia – A fabric fiber with an intermediate modulus will be used to avoid the transition. – Thus internal reinforcement will be made around the edges. We are contacting Hexcel (http: //www. hexcel. com) experts for advice. 11/6/2020 15

Xenon Detector Platform Installation • Movable stage for the xenon detector – Operating position – “Parking” position 2 • Mounting activity at PSI by Pisa group – started on 4/June and finished on 9/June • Tested successfully with 1. 6+0. 6 ton weights on it. 1 11/6/2020 3 16

Necessary Operation • 11/6/2020 After the windows are welded on the two vessel, we need to do the following operation: – – – A leak test on the window welds A pressure test closing all the aperture and covers. After pressure tests of two vessels are done, we have to perform a leak test again. – – – The PMT support structure is installed and adjusted. The attachments are welded on the cold vessel. A temperature sensors, heaters are installed. The two vessels are assembled together. – – – The connection between them are done. Bellows are welded. A leak test of those weld is done. A cleaning and hand polishing is done on the cold vessel. – – A cryogenic test is performed. After the cryogenic a leak test is performed again. 17

Cryostat Construction Schedule • • 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 (2 days) – 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 (1 day); cold window test box (3 days). – Welding of warm window on the test box (2 days) + helium leak test (1 day)+ mechanical test (1 day). – Machining of cold vessel (5 days). Week 3 -7 July: – Welding of cold window on the test box (2 days)- helium lesk test (1 day). – New honeycomb delivered – mechanical test cold window (1 day). – Welding window on cold vessel (2 days) Week 10 -14 July: – Test warm vessel (2 days). – Helium test of cold window (1 day) – Honeycomb mounting and cold test preparation (1 day) – Pressure test cold vessel, 4 bar, (1 day) 11/6/2020 • • • Week 17 -21 July: – Dry out cold vessel (1 day)- helium leak test of metallic sealing on covers (1 day). – Mounting of the phototube supporting structure (2 days) – Welding of the L bracket to hold the arches (phototube supporting structure) (1 day) – Installation of super insulation and temperature sensors (1 day) Week 24 -28 July: – Alignment and vessel integration (3 days) – Bellows welding (3 day) Week 31 July - 4 Agust: – Helium leak test on the welds (1 day) – Internal polishing (3 days) – Cleaning and dryout (2 days) Week 7 - 12 August: – Preparation and installation of equipmnets for the cryocenic test (1 day) – Cryogenic test (4 days) Week 14 - 18 August: – Helium leak test of cold vessel (2 days) – Prepartation of shipmenet (2 days) Week 21 - 26 August: – Delivery to PSI 18

PMT Final Delivery Insertion to holders Room temperature test 11/6/2020

PMT Final Delivery and Test Status • Newly delivered PMTs (~250) in 2006 – LP 4 th PMT test Vacuum break • 100 new PMTs tested, finished on 17/Mar/2006 – Pisa test facility • Test of 102 PMTs finished on 12/May/2006 • 50 more PMTs (delivered in June) will be tested. • Delivered PMTs (We need 846 PMTs in total) Chlorine HCl Silica – 870 PMTs ordered and delivered – 107 PMTs returned and ~120 PMTs will be returned (t>0. 3 mm) to Hamamatsu – 264 PMTs delivered for replacement Al Metal Tube Hamamatsu investigated further • 5 PMTs w/ large tilt but w/o any remaining chlorine • High temp/humidity test OK 11/6/2020 t 20

5 PMT Installation 6 1 7 2 3 11/6/2020 8 4 9 21

PMT Installation cont’d • • Window slope measurement – Done for all PMTs Installation status – Side : 40 (out of 48) holders ready. PMTs with large D(≥ 0. 3 mm) have been replaced. • Once installed, but later Hamamatsu provided replacements. • Inner, Outer, Top/Bottom Side – Outer : 18 (out of 22) holders ready – Inner : 18 (out of 24) holders ready – Top/bottom: not started yet Inner holders are located in a vacuum chamber (LP cryostat) to remove humidity as much as possible before installation to the detector 11/6/2020 22

PMT test before installing into the detector • Signal check before installing into the detector • NIM HV module • Oscilloscope • Measurements – All cable connections are checked simultaneously – Current (m. A) at 800 V – Pedestal distribution 11/6/2020 23

Assembly hut Air Filter 11/6/2020 24

Liquid H 2 Target and Na. I Detector 11/6/2020

p 0 Calibration Anti Counter g up p 0 g • p-p p 0 n • Need Anti-Counter (Na. I) at the opposite side – p 0(28 Me. V/c) – 54. 9 Me. V < E( ) < 82. 9 Me. V – Movable to scan the acceptance – Timing counter (Pb+Scinti) in front of the Na. I detector for timing calibration down target • E q E 170 o p 0 Requiring q>170 o 175 o FWHM = 1. 3 Me. V E Another interesting possibility – Abandon Na. I detector in coincidence – Detect one with the xenon detector – Convert another in a 0. 1 X 0 converter close to the H 2 target – Detect conversion and measure conversion point with a “special counter” – Measure e+ branch of the pair in the chambers Requiring q > 175 o FWHM = 0. 3 Me. V q 11/6/2020 • H 2 target and Na. I detector with a movable stage are essential. 26

Liquid Hydrogen Target • Liquid Helium Cooling • Installed to the position through the insertion tube • Thin entrance window (100 micron Mylar) 11/6/2020 27

Liquefaction Test • Several tests – Super-insulation – Material of LHe inlet • In the last test we liquefied some hydrogen – Terminated because of exhausting available helium 11/6/2020 28

Na. I Mover Construction • 3 x 3 Na. I crystals • For covering the xenon detector acceptance – +/-30 cm in z – +/-60 o in f – and +/-30 o in q • All motions are motordriven and remotely controllable 11/6/2020 29

Detector Preparation Status • 3 x 3 Na. I crystals • Readout electronics – APD Hamamatsu S 8664 -55 • 2 on 1 crystal • BD voltage ~400 V, 5 mmx 5 mm – Pre-AMP GND GN-0261 – (Shaper) – Temperature monitor and control • PT 100 • Peltier – Plastic scintillator (+Pb converter) with fine-mesh PMTs for timing calibration – Simulation • Just started 11/6/2020 30

Cryogenic/gas system 11/6/2020

Cryogenic/Gas system 11/6/2020 32

Slow Control 11/6/2020

Slow Control Xenon Detector System Storage pressure, valves Gas purifier valves, flow meter, pressure reducer control 1000 L dewar valves, pressure, temperature, refrigerator control, LN 2 flow, heater Detector Valves, pressure, temperature, surface level, strain gauge, refrigerator control, LN 2 flow, heater Liquid purifier Valves, surface level, level control, LN 2 flow Na. I mover Motor control, position sensor 11/6/2020 34

Scheme SCS Module 2 Gas Purifier SCS Module 1 Storage SCS Module 4 Detector liquid Purifier SCS Module 3 1000 L Dewer Network Xenon SC Backend PC Backend backup The backend PC handles signals between SCS modules 11/6/2020 Xenon Lab. View Interface Status History Display SCS Module 0 Na. I Mover MSCB Ethernet Adapter Main Slow Control Logging & Alarm 35

Measurements of UV light reflection on Al and PEEK • We asked spectroscopic LENS laboratory in Firenze to perform some measurements and to provide us experimental data about the properties of – PEEK (used in the inner holders) – Aluminium (used in the others) (we are very grateful to them for their kindness and helpfulness). Reference frame for the measurements: qinc = = = 300 450 600 qref =+300 =-300 qref qinc Laser beam linc = 160 nm (UV light). 11/6/2020 • Results indicates • >10% reflection on Al Movable optical prism • negligible on PEEK • Checking with LP data 36

Schedule 11/6/2020

Schedule • Cryostat delivery at the end of August • PMT assembly installation and cabling takes 35 days. • Detector setup (evacuation, liquefaction, purification…) takes 45 days • Detector can be ready in November – DAQ can be started when liquefaction finishes – p 0 calibration at the end of 2006 run 11/6/2020 38

Up-to-date Schedule • Now on Google Calendar (public) • http: //www. google. com/calendar/embed? src=3 ci 8 a 2 d 11 cqeogq 7 g 99 j 5 sssm 8%40 group. calendar. google. com 11/6/2020 39