Status overview of the cooling 31 August 2015 Bart Verlaat, Raphael Dumps 1

Progress points Many progress wrt the Velo evaporator concept and safety system is achieved. –Connector-less evaporator concept (CLEC) intensively discussed and getting more and more accepted –Tertiary vacuum concept based on CLEC on top secondary extension is also becoming the baseline in peoples thinking –Discussions with mechanics people (Liverpool) will continue in Velo module 0 meetings on Tuesdays. With a frozen evaporator concept the safety system can be designed –Test set-up under construction at CERN to study impact of a leak (Vacuum-pressure vs CO 2 leaked mass) –Test set-up will / can be used to test safety system Sizing of regulation valves in the manifolds have started. –A study for new control valves –Valve size calculations 2

The Connector-Less Evaporator Concept (CLEC) 3 Module with long tubes and feedthrough connector mounted on the assembly jig. Connectors and tubes are brazed to the microchannel before module assembly The cooling lines are unrolled prior to installation. The lines are routed on the side of the module base The feedthroughs are bended towards tertiary vacuum by an access hole in the secondary vacuum stand-off Expected rolled up size: ca 10x10cm Connectors can be fixed to manifold in the tertiary vacuum box Tertiary vacuum with CO 2 manifolds

All Upgrade Velo concept vs current Velo 4 All inlet capillaries on 1 side. Return common (Manifold inside) Electronics crates Cable feedthrough Tertiary vacuum with manifolds and safety valves Cooling feed through with thermal stand-off Out of the way space for cooling connector and flexible part Cooling lines passing the module base on the side Access flange

Cooling feed through 5 2x 1/8” VCR Gland (D=1/4”) 1/8” VCR glands without nuts are very small and fit both through a 14mm hole (10mm would even work when staggered) A split nut à la IBL can be installed after insertion Hole diameter 10-14mm Braze connection (Cold) O ring or copper seal connection (Warm) Mounting possible from both sides Atlas-IBL cooling line D gland flange =1/4” (6.35mm) VCR split nut 1/8” VCR with split nut Split nuts assembled after insertion Custom Standard Conflat

Prototype 6 Tubes are firmly fixed to the base by an insulator spacer 2 spools with a diameter of 50mm, length 1.2m. (Can be roll on a better support) Welded standard vacuum feedthrough CF15 on a stainless steel flange Welded tubes on a vacuum feed trough (thermal insulator) Temporary holding support 2x module pitch Connector can be used for testing (With connector saver), vacuum feedthrough as well

7 D=1/4” (6.35mm) 1/8” VCR with split nut mounted after tube insertion (gain of space) Installation of the connector through the vacuum flange

Venting CO 2 in vacuum g/m3 => v=285 m3/kg Far off scale Ca 350 kJ/kg*1.6 g = 560 J to heat it up to ambient. Condition of -30 ⁰ C liquid Condition of +20 ⁰ C low pressure gas Module volumes and CO 2 -30ºC liquid (1076 kg/m 3 ): –Total module volume (1.42 mL): 1.6 gram CO2 total Vacuum volumes (Eddy Jans memo, 5 November 2009) : –Secondary: 450 liter –Primary: 1715 liter –Maximum dP=10 mbar Loosing 1.6 gram of CO2 in the secondary volume gives a density of 1.6 g / 450 l = 3.5 g/m3 –3.5 g/m3 density after warming up to 20’C gives a pressure of 1.9mbar –Direct expansion without heat pick-up is ca half of the pressure 1 branch leakage is not problematic when proper shut-off

Possible shut- off concepts 9 No-return valves or active valves are under consideration.

CO 2 pumping in secondary vacuum 10 Pressure (mbar) Mass flow (g/s) ACP 28 pumping capacity for CO 2 A constant CO 2 leak of 0.1 g/s is tolerable (Almost a full microchannel flow) At least 1 ACP28 pump is active, sometimes 2 work in parallel

Proposed test set-up liter (Current Velo = 450 liter, upgrade will likely to be less due to smaller hood) PT,TT TT PT,TT TT Condensed reference volume Condenser to regulate CO 2 temperature to be vented Borrowed from Nikhef FT

Concept Evaporator P&ID 12 vent 6 8 ⅜” EH106 TT106 TS PV110 BD108 PT108 TT108 PV108 PV144 SV042 SV043 MV042 AV108 nc MV050 MV052 TT35036 NV110 MV110 CV142 nc no ¼” ½” PT050 To UT-Detector EH39052 TT39052 CV39052 EH30036 CV30038 PV30038 NV30142 NV30148 NV30242 NV30248 NV30342 NV30348 nc EH35036 CV35038 PV35038 NV35142 NV35148 NV35242 NV35248 NV35342 NV35348 PV35052 nc PV35040 nc PV35050 nc PV39060 nc PV39030 nc PV30040 nc PV30050 PV59032 PV59054 PV49060 PV49030 nc 36 PT35052 TT35052 BD PT35038 TT SA35052 SA30052 PT30038 TT Safety vent By-pass with dummy load Pre-heater Safety vent Pre-heater nc PV PT30052 TT30052 BD30052 TT39032 PT39032 BD TT PT39058 TT39058 BD Vacuum Ambient

Carel valves for CO 2 applications 13 Manual valves we generally use The Carel vales for CO 2 well cover our application range. A manual knob is also available Q = ca. 100xCv (kW) for dP=15 bar 21 kW 4.9 kW 1.1 kW

Valve sizing Flow distribution concept: –DP control of main liquid flow via by-pass –MF control of individual branches with a fixed DP To select the proper valve a Matlab simulation tool is set-up –Example shown for Lucasz plant. Evaporator data of velo and UT is needed to calculate LHCb plant case 14 FT Control Valve DP FT Controlled liquid flow Common 2-phase return Constant flow Flow control DP control

Conclusions The discussions with the VELO about the cooling / safety configuration are progressing, people start to focus towards the same direction –Safety system study at CERN? Most input for system manifold is arriving, so concept can progress sufficiently for sizing towards transfer line and plant 15