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 Cooling Update Rob van Weelderen, Cryogenic Group, Technology Department, CERN

Overview Heat Loads + Explicit Design Margins Heat Loads + Explicit Design Margins IT - Bayonet Heat Exchangers IT - Bayonet Heat Exchangers Beam-screen piping at 5 K – 20 K Beam-screen piping at 5 K – 20 K IT – PID (for beam-screen at 5 K – 20 K) IT – PID (for beam-screen at 5 K – 20 K) IT – PID (for beam-screen at 40 K – 60 K) IT – PID (for beam-screen at 40 K – 60 K) IT – Piping IT – Piping Other Magnets (D2, Q4, Q5, Q6) Other Magnets (D2, Q4, Q5, Q6) 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 needed CP,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 ICs10 cm gap in ICs250 cm gap in ICs50 cm gap in ICs3 Magnet cold massBeam screenMagnet cold massBeam screen Q1A + Q1B Q2A + orbit corr Q2B + orbit corr Q3A + Q3B CP D Interconnects Total However these loads have to be corrected for the expected 10 % transparency of the Titanium absorbers material with respect to the Pure Titanium used for the Fluka calculations + additional loads - 

D1 & IT: heat loads Corrected for 10 % tungsten transparancy Heat Loads: secondairies (W)10 cm gap in ICs10 cm gap in ICs250 cm gap in ICs50 cm gap in ICs3 Magnet cold massBeam screenMagnet cold massBeam screen Q1A + Q1B Q2A + orbit corr Q2B + orbit corr Q3A + Q3B CP D Interconnects beam-screen contact load28 static heat load28 cryostat ends16 electron cloud0000 image currents???? Total beam-screen contact load0.5W/m static heat load0.5W/m cryostat ends16W electron cloud0W image currents?W Assuming no electron cloud we have already: 764 W Assuming image currents 0.5 W/m on BS (tbc) : 751 W What will be our design choice? Propose + 20 % margin ~ 920 W at 1.9 K, 785 W at BS IT ~ 690 W, D1+CP ~ 230 W, Beam screens ~ 785 W

Targeting 690 W means: HX inner diameter 80 mm, Yoke hole 89 mm

Next slides need updating !

Beam-screens with 16 mm & 6 mm Tungsten Q2-D1, 291 kg, 4 x 4.4 mm ID Q1, 515 kg, 4 x 14.4 mm ID Courtesy R. Kersevan

Have to split beam-screen & BLM cooling between (Q1 – Q3) & (CP – D1) Cryogenically working 40 K – 60 K would be better Cooling possibility at these T-levels under investigation