1. Cooling Update (25 February 2014)
Rob van Weelderen,
Cryogenic Group, Technology Department, CERN

2. Overview Heat Loads + Explicit Design Margins
IT - Bayonet Heat Exchangers
Update of Update at next video meeting!

3. 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

4. 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 -

5. 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 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 ?

6. Targeting 686 W means:
HX inner diameter ~78 mm, Yoke hole ~88 mm

7. Targeting 686 W with split pumping option means:
HX inner diameter ~57 mm, Yoke hole ~65 mm

8. 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 W with 2x68 ID HX’s (2x77mm Yoke holes).
Total IT+CP+D1 heat extraction capacity using split pumping option 1050 W – 1200 W