The HiLumi LHC Design Study (a sub-system of HL-LHC) is co-funded by the European Commission within the Framework Programme 7 Capacities Specific Programme, Grant Agreement 284404.

Cooling Update(25 February 2014)

Rob van Weelderen, Cryogenic Group, Technology Department, CERN

Overview• Heat Loads + Explicit Design Margins

• IT - Bayonet Heat Exchangers

Update of Update at next video meeting!

Placing of cryo-equipment considered (variant 4)

• Phase-separator &• Piping entries/exits

• Phase-separator &• Piping entries/exits• QRL-jumper

• SM &• QRL-jumper• Phase-

separator• Piping

entries/exits

actively cooled

Q1,Q2a,Q2b,Q3: actively cooled for about 41 m, double-HXs neededCP,D1 : actively cooled for about 16 m, double-HXs needed

actively cooled

D1 & IT: heat loads

Courtesy L. S. ESPOSITO

Heat Loads: secondairies (W) 10 cm gap in ICs 10 cm gap in ICs2 50 cm gap in ICs 50 cm gap in ICs3

Magnet cold mass Beam screen Magnet cold mass Beam screen

Q1A + Q1B 100 175 100 170

Q2A + orbit corr. 95 60 100 65

Q2B + orbit corr. 115 80 120 80

Q3A + Q3B 140 80 140 80

CP 55 55 60 55

D1 90 60 90 60

Interconnects 20 140 20 105

Total 615 650 630 615

However these loads have to be corrected for the expected 10 % transparency of the Tungsten absorbers material with respect to the Pure Tungsten used for the Fluka calculations

+ additional loads -

D1 & IT: heat loadsCorrected for 10 % tungsten transparancyHeat Loads: secondairies (W) 10 cm gap in ICs 10 cm gap in ICs2 50 cm gap in ICs 50 cm gap in ICs3

Magnet cold mass Beam screen Magnet cold mass Beam screenQ1A + Q1B 117.5 157.5 117 153Q2A + orbit corr. 101 54 106.5 58.5Q2B + orbit corr. 123 72 128 72Q3A + Q3B 148 72 148 72CP 60.5 49.5 65.5 49.5D1 96 54 96 54Interconnects 34 126 30.5 94.5beam-screen contact load 28 28 28 28static heat load 28 28 28 28cryostat ends 16 16 16 16electron cloud 0 0 0 0image currents ? ? ? ?Total 753 658 764 626

beam-screen contact load 0.5W/mstatic heat load 0.5W/mcryostat ends 16Welectron cloud 0Wimage currents ?W

Q1-Q2A ~ 260 W, Q2B-Q1B ~ 310 W, D1+CP ~ 195 W,Beam screens ~ 785 W

Assuming no electron cloud we have already IT+D1: 764 WAssuming image currents 0.5 W/m on BS (tbc) : 655 W

What will be our design choice?

Propose + 20 % margin ~ 920 W (686 @IT) at 1.9 K,785 W at BS

Targeting 686 W means:

HX inner diameter ~78 mm, Yoke hole ~88 mm

Targeting 686 W with split pumping option means:

HX inner diameter ~57 mm, Yoke hole ~65 mm

Notes:• At 800 W on the Q1-Q3B the split option starts

to break down due to vanishing T-regulation margin (but can still “work”)

• D1 can extract ~250 W with 2x49mm ID HX’s (2x58mm Yoke holes): about 350-400 W with 2x68 ID HX’s (2x77mm Yoke holes).

• Total IT+CP+D1 heat extraction capacity using split pumping option 1050 W – 1200 W