1. SBND Cryostat Requirements David Montanari, Michael Geynisman, Dimitar Mladenov, Joe Howell 14 October 2015

2. Introduction Same cryostat requirements as presented for the past months. Same layout of penetrations at the top as presented by Joe H. in Aug 2015. Discussions between CERN and Fermilab on layout of top plate ongoing. Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design2

3. ParameterValue Type of structureMembrane cryostat (5% ullage) Membrane material SS 304/304L, 316/316L or equivalent. Other materials upon approval. FluidLiquid Argon (LAr) Outside reinforcement (Support structure) Self standing steel enclosure. Might include embedded heaters to prevent steel from freezing (Floor + Sides) TPC size (with field cage and frame) Width: 4,312 mm (Transvers to beam) Length: 2 x 2,656 = 5,312 mm (Parallel to beam) Height: 4,294 mm Minimum clearance of TPC (Back)1,200 mm (CPA bar to the tip of corrugation) Minimum clearance of TPC (Front)375 mm (CPA bar to the tip of corrugation *) Minimum clearance of TPC (Sides)375 mm (CPA bar to the tip of corrugation *) Minimum clearance of TPC (Floor)400 mm (CPA bar to the tip of corrugation *) Depth of LAr above TPC400 mm (Above the CPA frame) Minimum depth of liquid argon5,164 mm (From the floor) Maximum static heat leak 15 W/m 2 (Sides/Floor) 20 W/m 2 (Roof) Cryostat requirements – 1 Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design3 Note (*): The TPC clearances are set to avoid high voltage breakdown

4. ParameterValue Vapor barrierStainless steel plates (part of support structure) Insulation thickness600 mm Secondary barrierGTT design (sandwiched within the insulation). Liquid tight. Membrane thickness (GTT)1.2 mm (assumed 2 mm to calculate external dimensions) Corrugation height70 mm Minimum inner dimensions cryostat (Same as last iteration) 5,202 mm (Transv) x 7,027 mm (Para) x 5,423 mm (H) * (flat plate to flat plate) Operating gas pressurePositive pressure. Nominally 70 mbar (~1 psig) Design Pressure345 mbarg (~5 psig) Membrane leak tightness1E-6 mbar*l/sec Penetrations -1 side penetration through the membrane at the lowest possible/practical elevation for LAr circulation and purification. Downstream of beam. Location and size TBD. Lifetime10 years (5 years of run + 5 years potential upgrade) Thermal cycles20 cool down and total warm-up Cryostat requirements – 2 Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design4 Note (*): the height is fine with either a flat metal plate without corrugations (invar or similar) or corrugated membrane panels.

5. ParameterValue Configuration Self standing steel enclosure. Might include embedded heaters to prevent air condensation on the outside of the veto (Floor + Sides). Vapor barrier6 mm SS 304L plates connected to the I-beams of the support structure Minimum inner dimensions 6,406 mm (Transv) x 8,231 mm (Para) x 6,627 mm (H) * (flat plate to flat plate, inner of vapor barrier) Design Pressure345 mbarg (~5 psig) LAr + GAr load -384 ton (Bottom) -200 ton (Long side) -148 ton (Short side) Uplift force (top)-126 ton (GAr) Additional loads -Loads transferred from the top plate down to the support structure -Veto (2,500 kg each side wall, 2,00 front/back walls) Seismic loadSee SB DocDB n. 274 Penetrations -1 side penetrations from the inner membrane at the lowest possible/practical elevation for LAr circulation and purification. Downstream of beam. Exact location and size TBD. -4 side penetrations for GAr purge in insulation (2 In, 2 Out). Location and size TBD. Maximum deflection towards outside 50 mm (for veto) Design codeBeing discussed 5Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design Outer structure requirements – 1 Note: It has to fit inside the building leaving enough space for ES&H requirements, LAr pumps placement, etc.

6. ParameterValue Roof configuration Two metal plates reinforced with profiles/beams anchored to the outer support structure to match an opening in the roof: -One removable plate with TPCs hung underneath, containing all penetrations for the TPC, light detection and laser calibration systems (With the exception of the HV feedthroughs). If welded, provisions shall be made to allow for removal and re-welding six (6) times. -One fixed plate containing all the penetrations and services for the cryostat and cryogenics and the TPC HV feedthroughs. Dimensions To match the cryostat and the DAB door for transportation of top plate + TPC anchored underneath. Plate Trusses non-wet material Steel if room temperature. SS 304/304L or equivalent if at cryogenic temperature. Wet materialSS 304/304L, 316/316L or equivalent. Other materials upon approval. FluidLiquid Argon (LAr) Design Pressure345 mbarg (5.0 psig) Design Temperature77 K (liquid Nitrogen temperature for flexibility) Maximum allowable roof deflection0.003 m differential between APA and CPA (*) Pressure stability inside the tank No requirement, as long as the roof deflection is within the limit. Same for atmospheric pressure variations. 6Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design Cryostat top requirements – 1 Note (*): This may require to mechanically decouple the TPCs from the top.

7. ParameterValue Maximum static heat leak20 W/m 2 (Greater than sides/bottom to allow for penetrations, etc.) Max vibration No problem < 1 kHz Worst is 100 kHz Additional design loadsSBN DocDB n. 552 Seismic loadSBN DocDB n. 274 TPC anchorsSBN DocDB n. 552 Grounding plateSee Linda’s talk. Lifting fixtures Appropriate for positioning the top and the different parts that constitute it. Penetrations list, type, locationSBN DocDB n. 552 Clear space around each penetrationSBN DocDB n. 552 Lifetime10 years (5 years of run + 5 years potential upgrade) Thermal cycles20 cool down and total warm-up 7Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design Cryostat top requirements – 2

8. Removable top plate list of penetrations Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design8

9. Removable top plate layout Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design9

10. Fixed top plate list of penetrations (sample) Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design10

11. Clear space around penetrations Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design11

12. Transportation/Access needs TPCs will be assembled and installed under the top plate in the DZero Assembly Building (DAB): –Available Height: 6,083 mm (per Joe H.) –Available width: 5,790 mm. Current preliminary dimensions of Top plate + TPC: –Height (including TPC): see next slide. –Width: 5,304 mm. Need to add transportation equipment and design a support scheme for transportation. Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design12

13. Height (from Joe H. Oct 14, 2015) Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design13

14. Summary Oct 14, 2015David M, Michael G, Dimitar M, Joe H | SBND Cryostat Design14 The inner dimensions of the membrane cryostat (flat plate to flat plate) are: 5,202 mm (Transverse) x 7,027 mm (Parallel) x 5,423 mm (Height). Adding 600 mm of insulation and 2 mm of membrane (rounded for calcs), the inner dimensions of the outer support structure are: 6,406 mm (Transverse) x 8,231 mm (Parallel) x 6,627 mm (Height). Two top plates (one may be integral part of the cryostat): –One fixed with all cryo penetrations + HV. –One removable with the TPC hung from underneath and the TPC penetrations, laser calibrations and light detection. –Details of the in SBN DocDB n. 552. During the design of the top plate, the limitations of the DAB door needs to be taken into account to verify the available height and width.