Cooling Update (27 March 2014) Rob van Weelderen, Cryogenic Group, Technology Department, CERN

Overview Fluka Heat Loads + Explicit Design Margins 1.9 K Heat load limits for IT with – double HX in Q1 to Q3 + intermediate pumping 1.9 K Heat load limits for D1 – CP with –single HX and with/without intermediate pumping Beamscreen cooling

Placing of cryo-equipment considered (variant 4) Additional low pressure pumping ? actively cooled: 2 x HX actively cooled: 1 x HX ? 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, single-HXs desired

D1 & IT: Fluka heat loads However these values have to be augmented due to additional loads  Courtesy L. S. ESPOSITO

D1 & IT: Fluka + additional heat loads Heat Loads (W) 50 cm gap in ICs 50 cm gap in ICs3 Magnet cold mass Beam screen Q1A + Q1B 110 150 Q2A + orbit corr. 105 50 Q2B + orbit corr. 130 70 Q3A + Q3B 160 60 CP 45 D1 (160 mm) 100 Interconnects 25 85 beam-screen contact load 27 -27 static heat load cryostat ends 16 electron cloud image currents ? Total 771 633 Q1-Q2A ~ 247 W, Q2B-Q1B ~ 322 W, D1+CP ~ 202 W, Beam screens ~ 633 W Image currents 0.5 W/m on BS (tbc) What will be our design choice? Propose + 20 % margin: ~ 925 W at 1.9 K, ~ 759 W at BS beam-screen contact load 0.5 W/m static heat load cryostat ends 16 W electron cloud 150 image currents ?

Minimal need (569 W) Practical T-regulation limit, (800 W) Hard limit, HX overflowing (1000 W)

D1 + CP (~14.9 m long) needed 202 W without contingency "Power (W)" "Double HX ID (mm)" "single HX ID (mm)" 50 24 32 100 44 150 38 53 200 61 250 49 300 350 57 400 - Limited by vapour velocity (green is ok) - No good regulation possible/HX-area (red, forbidden) Using a full length double HX: 250 W at 2x49 mm ID, 2x58 mm Yoke-holes Using a full length single HX : 125 W at 1x49 mm ID, 1x58 mm Yoke-hole Not enough! "Power (W), 6m 1HX" "single 6m long HX ID (mm)" 40 35 45 50 55 60 65 70 75 - Intermediate pumping between CP and D1 and with single HX, limited by HX-area