1. Liquid Xenon Detector
Xenon Detector Group
2018/11/18

2. Cryostat Construction PMT Cryogenic/Gas System
Contents
Cryostat Construction
PMT
Cryogenic/Gas System
(Calibration  Carlo’s presentation)
Liquid H2 Target and NaI Detector
Slow Control
Measurements of UV Light Reflection on Al and PEEK
Schedule
2018/11/18

3. Vessels Windows Status & Schedule
Cryostat
Vessels
Windows
Status & Schedule
2018/11/18

4. 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:
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.
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2018/11/18

5. Construction Procedure
Assemble and weld
Leak test
Machining
Warm
Pressure & Leak test
Assemble and weld
Assemble two vessels
Weld Chimneys
Leak & Cryogenic tests
Install Windows
Install sensor, PMT support attachment, etc.
Assemble and weld
Leak test
Machining
Cold
Assemble and weld
Pressure & Leak test
Step Step Step Step 4
2018/11/18

6. Warm/Cold Vessels
Dec/ 2005
Feb/ 2006
Apr/ 2006
Apr/ 2006
2018/11/18

7. Leak Test before Machining
The cold and warm vessels were leak tested using provisory covers.
Cold vessel test 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
1Bar Pressure
Outer Vessel OK
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.
With Cover
1Bar Pressure
2018/11/18

8. Machining 1 Cold Vessel 3 Warm Vessel 2 Middle of June 4
Cu cooling pipe will be welded on the back
Warm Vessel 3 2
Middle of June 4
2018/11/18

9. Bellows/Chimneys
Pressure Test OK
Up to Dp=4Bar
2018/11/18

10. Windows Honeycomb/CF panel Cold Window Intermediate 5mm frame
A thin foil is welded to a 5mm thick intermediate frame.
Backing with a honeycomb/carbon fiber panel for the cold window.
Honeycomb/CF panel
Cold Window
Intermediate frame
Honeycomb/CF panel
Weld
Weld
Cross section A-A’
Al honeycomb
0.4mmt window CF
Intermediate 5mm frame
Intermediate 5 mm frame
Weld
weld
2018/11/18

11. 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
Warm window test box
Cold Window
Warm Window
Pressure
Pressure
Cold window test box
Honeycomb/CF panel
Leak test
2018/11/18

12. 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.
2018/11/18

13. 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.
2018/11/18

14. 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 3.0Bar)
The honeycomb/CF panel broke at one side.
FEA with sophisticated laminated elements  OK
This buckling is attributed to local defects.
Carbon Fiber
Al honeycomb
Transition area
OK on this side
2018/11/18

15. 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
weld
Cold Vessel
Warm Vessel
Honeycomb/CF panel
Cold Vessel
Weld
Weld
Warm Vessel
Turn up the edges and weld along them
2018/11/18

16. 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.
We are contacting Hexcel ( experts for advice.
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/m3.
New design
8 piles of fibers
Total thickness of 1.0mm
A thicker honeycomb 24 mm with the same density (50kg/m3) 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.
2018/11/18

17. Xenon Detector Platform Installation
Movable stage for the xenon detector
Operating position
“Parking” position
Mounting activity at PSI by Pisa group
started on 4/June and finished on 9/June
Tested successfully with ton weights on it. 2 1 3
2018/11/18

18. Necessary Operation
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.
2018/11/18

19. Cryostat Construction Schedule
Week 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 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 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 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 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 August:
Preparation and installation of equipmnets for the cryocenic test (1day)
Cryogenic test (4days)
Week August:
Helium leak test of cold vessel (2days)
Prepartation of shipmenet (2days)
Week August:
Delivery to PSI
2018/11/18

20. Final Delivery Insertion to holders Room temperature test
PMT
Final Delivery
Insertion to holders
Room temperature test
2018/11/18

21. PMT Final Delivery and Test Status
Vacuum break
Chlorine
Newly delivered PMTs (~250) in 2006
LP 4th PMT test
100 new PMTs tested, finished on 17/Mar/2006
Pisa test facility
Test of 102PMTs finished on 12/May/2006
50 more PMTs (delivered in June) will be tested.
Delivered PMTs (We need 846 PMTs in total)
870 PMTs ordered and delivered
107 PMTs returned and ~120 PMTs will be returned (t>0.3mm) to Hamamatsu
264 PMTs delivered for replacement Al
Silica
Metal Tube
HCl
Hamamatsu investigated further
5 PMTs w/ large tilt but w/o any remaining chlorine
High temp/humidity test  OK t
2018/11/18

22. PMT Installation 5 6 1 7 2 8 3 4 9
2018/11/18

23. PMT Installation cont’d
Window slope measurement
Done for all PMTs
Installation status
Side : 40 (out of 48) holders ready. PMTs with large D(≥0.3mm) have been replaced.
Once installed, but later Hamamatsu provided replacements.
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
Inner, Outer, Top/Bottom
Side
2018/11/18

24. 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 (mA) at 800V
Pedestal distribution
2018/11/18

25. Assembly hut
Air Filter
2018/11/18

26. Liquid H2 Target and NaI Detector
2018/11/18

27. p0 Calibration
Anti Counter
p-pp0n
p0(28MeV/c)  g g
54.9 MeV < E(g) < 82.9 MeV
Need Anti-Counter (NaI) at the opposite side
Movable to scan the acceptance
Timing counter (Pb+Scinti) in front of the NaI detector for timing calibration
Another interesting possibility
Abandon NaI detector in coincidence
Detect one g with the xenon detector
Convert another  in a 0.1X0 converter close to the H2 target
Detect conversion and measure conversion point with a “special counter”
Measure e+ branch of the pair in the chambers
H2 target and NaI detector with a movable stage are essential. g up p0 g
down
target q Eg
170o
175o q Eg Eg p0
Requiring q>170o
FWHM = 1.3 MeV
Requiring q > 175o
FWHM = 0.3 MeV
2018/11/18

28. Liquid Hydrogen Target
Liquid Helium Cooling
Installed to the position through the insertion tube
Thin entrance window (100 micron Mylar)
2018/11/18

29. Liquefaction Test Several tests
Super-insulation
Material of LHe inlet
In the last test we liquefied some hydrogen
Terminated because of exhausting available helium
2018/11/18

30. NaI Mover Construction
3x3 NaI crystals
For covering the xenon detector acceptance
+/-30cm in z
+/-60o in f
and +/-30o in q
All motions are motor-driven and remotely controllable
2018/11/18

31. Detector Preparation Status
3x3 NaI crystals
Readout electronics
APD Hamamatsu S
2 on 1 crystal
BD voltage ~400V, 5mmx5mm
Pre-AMP GND GN-0261
(Shaper)
Temperature monitor and control
PT100
Peltier
Plastic scintillator (+Pb converter) with fine-mesh PMTs for timing calibration
Simulation
Just started
2018/11/18

32. Cryogenic/gas system
2018/11/18

33. Cryogenic/Gas system
2018/11/18

34. Slow Control
2018/11/18

35. Slow Control Xenon Detector System Storage Gas purifier 1000L dewar
pressure, valves
Gas purifier
valves, flow meter, pressure, pressure reducer control
1000L dewar
valves, pressure, temperature, refrigerator control, LN2 flow, heater
Detector
Valves, pressure, temperature, surface level, strain gauge, refrigerator control, LN2 flow, heater
Liquid purifier
Valves, surface level, level control, LN2 flow
NaI mover
Motor control, position sensor
2018/11/18

36. Status History Display
Scheme
SCS Module 2
Gas Purifier
SCS Module 1
Storage
SCS Module 0
NaI Mover
SCS Module 4
Detector
liquid Purifier
MSCB
Ethernet
Adapter
SCS Module 3
1000L Dewer
Network
Xenon SC
Backend PC
Backend
backup
Main Slow Control
Logging &
Alarm
Xenon LabView
Interface
Status History Display
The backend PC handles signals between SCS modules
2018/11/18

37. 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  qref =+300
qinc = 450  qref = 00
qinc = 600  qref =-300
qinc
qref
Laser beam
Results indicates
>10% reflection on Al
negligible on PEEK
Checking with LP data
linc = 160 nm (UV light).
Movable optical prism
2018/11/18

38. Schedule
2018/11/18

39. Cryostat delivery at the end of August
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
p0 calibration at the end of 2006 run
2018/11/18

40. Now on Google Calendar (public)
Up-to-date Schedule
Now on Google Calendar (public)
2018/11/18