1. DS20k Integration Workshop
CERN – 06/05/2019

2. Workshop Goals
Clarify and size all constraints related to the construction/installation of the DS20k experiment
Advance on the detector design:
TPC
Veto
Cryostat/Roof interface
Agree upon TPC assembly and test:
Location
Test dewar use
Lay out an installation procedure that takes into account all of the above.

3. Challenges
Few constraints that need to be tackled, as they impact all subsystems and installation
Seismics (Olga/Alberto ‘s slides)
Cryostat location, in relation to cryogenic installation
Cryogenics requirements
TPC
Radon – free environment
Roof occupancy

4. Seismic
The seismic parameters have been proposed and agreed with Gran Sasso autorities and Politec. Milano.
The seismic spectra have been calculated:
for personnel and equipment safety
for the cryostat and the infrastructure
for installation and for operation periods
We are waiting a feedback from the Italian authorities.
We are assessing the cryostat design (using these spectra) via different methods :
- EN Eurocode 8 (done)
- Seismic Response Spectrum (on going)
- Dynamic Response Analysis
We will check the eigen-frequencies of the DarkSide cryostat using NP04 and NP02 cryostat by determining experimentally their modal response.
From these analysis we will provide to the sub systems:
the frequency range to respect for their design
the expected seismic acceleration at their basis.

5. Cryogenics and Cryostat
Marco Carlini started exercise of integrating cryogenics, cryostat and services building in Hall C. Follow up depends heavily on
the presence of the test dewar in the hall,
the UAr storage solution
the final solution for cryogenics
Cryogenics: ProtoDUNE cryo plant can still be adjusted to Hall C geometry and the DS20k requirements (Hanguo’s document).
Interaction between Marco and CERN Cryo group will optimize this solution.
Interfaces with TPC/VETO
Insertion/extraction of UAr through Veto structure
Insertion/extraction of AAr – good circulation through Veto structure

6. Radon-free environement
The services building is going to be equipped with filtering for radon.
The cryostat must be equipped in the same way, if we want to protect installation (of the veto especially).
T0 for this requirement: as soon as cryostat can accept detector parts?
We have 4 man-holes. We can use one for filtering. The other ones must be protected while allowing personnel access and easy extraction (especially after Top-Cap is in place – confined space)
All penetrations must be protected as well, before they are closed.
Overall roof protection is probably preferable. Opening for crane operations must be foreseen.

7. TPC TPC Assembly: WHERE? (LNGS or Canada)
Test dewar: WHERE? (Outer Lab or Hall C)
Outer lab PROs:
Easier to equip a multi-purpose set-up.
Can receive lab support if it is made available for other experiments after DS20k is done.
More space available for Cryo/Electronics in Hall C.
Avoid sequential activities in the Hall C. More schedule flexibility.
Outer lab CONs:
Must find a dedicated building to set up a clean room with radon filtering.
Must set-up dedicated cryogenics.
TPC must travel, assembled, to the underground lab.
Assembled TPC transport to Hall C was discussed in January at LNGS.
Delicate but feasible.

8. TPC/2 Uses of test dewar: Annealing Clevios/TPB coating
TPC Assembly (with Photon detectors)
TPC test (in LAr)
Mechanical stability
HV stability
TPC operation (full drift)
TPC Hanging structure:
Should be the same for test and final operation.
Must be integrated in the dewar design.

9. Roof

10. Roof/2
Veto penetrations are still missing in the drawing (read-out/support)
Support for the veto must be defined (among the goals of this workshop), but it is preferred to have it on the roof.
An added support structure for this has been discussed.
Roof occupation is quite significant. From the point of view of Electronics racks placement, this must be taken into account.
We suggest to minimize occupation on the roof.
It was suggested to add a platform extending outside the roof:
feasible over Sabre?
seismic? Same as cryostat, since the structures are linked.

11. Cryostat To be defined: Final position, as a function of:
Assembly procedure
Cryo installation
TPC insertion
Use of moving crane?
Time and space available for:
Construction warm structure
Construction cold structure (Insulation+membrane, Gabadi)
Construction external access structure (to access the cryostat from above, after walls are in place) <--> Services building
TPC insertion:
Space and limitations
With (or without) Top-Cap

12. Hall C occupation To be decided position of: Electronics racks
Cryo installation
Power network
Slow control racks
Interaction with other experiments should be clear from the beginning.
Interaction with Sabre.
Use of platform above it? Time limitations?
Other cranes users?
Borexino?

13. DS-Proto Proto design should mimic DS20k as much as possible.
Goal: rescaling the design directly from 20k to Proto.
What can be rescaled without modifications?
What can/should be adjusted for Proto operation
Cryo system: the same for Proto and DS20k, or two identical but separated versions? One is preferable (tested), provided it can be moved/transported.