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) actively cooled actively cooled Phase-separator & Piping entries/exits Phase-separator & Piping entries/exits QRL-jumper SM & QRL-jumper Phase-separator Piping entries/exits Q1,Q2a,Q2b,Q3: actively cooled for about 41 m, double-HXs needed CP,D1 : actively cooled for about 16 m, double-HXs needed

D1 & IT: heat loads 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 Q1A + Q1B 100 175 170 Q2A + orbit corr. 95 60 65 Q2B + orbit corr. 115 80 120 Q3A + Q3B 140 CP 55 D1 90 Interconnects 20 105 Total 615 650 630 Courtesy L. S. ESPOSITO 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 loads Q1-Q2A ~ 260 W, Q2B-Q1B ~ 310 W, D1+CP ~ 195 W, Corrected for 10 % tungsten transparancy 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 Q1A + Q1B 117.5 157.5 117 153 Q2A + orbit corr. 101 54 106.5 58.5 Q2B + orbit corr. 123 72 128 Q3A + Q3B 148 CP 60.5 49.5 65.5 D1 96 Interconnects 34 126 30.5 94.5 beam-screen contact load 28 static heat load cryostat ends 16 electron cloud image currents ? Total 753 658 764 626 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 W Assuming 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 beam-screen contact load 0.5 W/m static heat load cryostat ends 16 W electron cloud image currents ?

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