1. Upgrade phase 1: Energy deposition in the triplet
Elena Wildner
Francesco Cerutti
Marco Mauri
24/01/08
Energy deposition, LIUWG, Elena Wildner

2. Energy deposition, LIUWG, Elena Wildner
Outline
Baseline, IR1 and IR5
Some basic considerations
The upgrade Phase I scenario
Simulation results
Continuation
Conclusion
24/01/08
Energy deposition, LIUWG, Elena Wildner

3. Work on the nominal insertion layout
Energy deposition studies independently Fermilab, 2002 & CERN, 2007 (LHC report 633 and LHC note to appear) with MARS and FLUKA
In addition comparisons have been made on representative toy model
Agreement 5 % in coils 20% in iron
Studies so far up to D1
24/01/08
Energy deposition, LIUWG, Elena Wildner

4. Models of baseline IR1 and IR5
Courtesy C. Hoa
Liner in Q1 and MCBX of thickness 6.5 mm (stainless steel)
Length 31 m
Magnet apertures 70 mm
Half crossing angle mrad
24/01/08
Energy deposition, LIUWG, Elena Wildner

5. Heat load along the triplet, “nominal”
To limit the peaks in the superconducting coils: our first objective
Luminosity= L0 (1 *1034 cm-2s-1)
Recommended limit
Q Q2a Q2b Q3
Courtesy C. Hoa
24/01/08
Energy deposition, LIUWG, Elena Wildner

6. Energy deposition, LIUWG, Elena Wildner
The scoring
Cable
We make the binning for the scoring so that it corresponds to a minimum volume of equilibrium for the heat transport (cable transverse dimensions, with a length corresponding to the twist pitch of the cable)
Total power deposited in the magnets
Important to know the volume of the magnet (the model has to be realistic)
The power deposited per meter of magnet
Azimuthal integration of the power in the longitudinal bins
Important for results to know how this is calculated and choose correct bin size!!!
Scoring volume: A*L
Transverse area of cable (A)
Length (L) 10 cm (twist pitch)
24/01/08
Energy deposition, LIUWG, Elena Wildner

7. Effect of Magnetic Field, nominal IR5
24/01/08
Energy deposition, LIUWG, Elena Wildner

8. Energy deposition, LIUWG, Elena Wildner
Effect of the TAS
Q1, TAS 40 mm aperture
”Symmetric” upgrade layout
Q1, no TAS
24/01/08
Energy deposition, LIUWG, Elena Wildner

9. Effect of Crossing Angle, nominal IR5
Total
Peaks
24/01/08
Energy deposition, LIUWG, Elena Wildner

10. Basic considerations (summary)
Beam Pipe
The beam pipe between magnets shields the front face of the downstream magnet
The experimental vacuum chamber before the TAS has to be properly integrated
We do not include the experimental vacuum chamber before the TAS in our calculations yet
TAS
The TAS protects essentially the first quadrupole
Magnetic field
The magnetic field is driving the deposited energy
Mask
A mask outside the magnet aperture does not affect the energy deposited in the cable
Crossing angle
The effect of the crossing angle is smaller than 20%
24/01/08
Energy deposition, LIUWG, Elena Wildner

11. Energy deposition, LIUWG, Elena Wildner
The layout, Phase I
“Symmetric”
TAS
Q Q2a Q2b Q3
IP1
130mm
130mm
130mm
130mm
9.40m
7.80m
7.80m
9.40m
41 m
Positive particle +
FDDF
Magnet
MQXC
Configuration
“Symmetric”
Gradient [T/m]
120
Aperture [mm]
130
Peak Field [T]
8.7
Layers 2
LHC Project Report 1000: “A Solution for Phase-one Upgrade of the LHC Low-beta Quadrupoles Based on Nb-Ti”,
J. P. Koutchouk, L. Rossi, E. Todesco
Half crossing angle: 220 m rad, vertical
For comparison: “Nominal” (L=L0) layout is about 30 m long.
24/01/08
Energy deposition, LIUWG, Elena Wildner

12. The Magnet/Field Model
Cold Mass outer diameter 570 mm
4 X MQXC
130 mm Aperture
270 mm
Courtesy: F. Borgnolutti
24/01/08
Energy deposition, LIUWG, Elena Wildner

13. Energy deposition, LIUWG, Elena Wildner
The magnet ends
The magnets have in this first study the same length as the magnetic length:
mechanical length = magnetic length
No coil ends are modeled (the same transverse layout over the whole magnet)
No 3D field or hard edge approximation
24/01/08
Energy deposition, LIUWG, Elena Wildner

14. Beam pipe dimensioning
Relation thickness (t) and diameter (D), valid for stainless steel: t = D
Example for 130 mm aperture quads (3.5 mm is the gap between coil and beam tube):
OD = 130 mm mm = mm
Thickness of beam pipe according to formula: t= 3.45 mm
ID = mm – 2*3.45 mm = mm
24/01/08
Energy deposition, LIUWG, Elena Wildner

15. “Baseline”or “reference” case, no shielding
Peak in coils
Luminosity = 2.5 L0
Minimum thicknesses for mechanical considerations:
Beam-Pipe 3.45 mm
Beam-Screen 2 mm
Ref. value for max energy deposition 4.3 mW/cm3
Q Q2a Q2b Q3
Continuous beam-screen and pipe, no experimental vacuum pipes
24/01/08
Energy deposition, LIUWG, Elena Wildner

16. Azimuthal heat deposition pattern, Q2a
24/01/08
Energy deposition, LIUWG, Elena Wildner

17. Beam-screen, case 3mm W-liner
OD = mm – 2 * 0.7 mm – 2 * 3 mm = mm
ID = OD – 2 * 2 mm = mm
Liner
Additional restriction on vertical aperture
Necessary Gap
108.2/2
102.61/2
Beam-Screen thickness
24/01/08
Energy deposition, LIUWG, Elena Wildner

18. Energy deposition, LIUWG, Elena Wildner
Liner dimensioning
Old Capillary Position
Beam-pipe and beam-screen as thin as mechanically possible!
Magnet aperture 130 mm same in all 4 magnets. s
Liner
Space CBT-BS [mm]
0.7
Coil Aperture [mm]
130
CBT Outer Diameter [mm]
126.5
CBT thickness [mm]
3.45
CBT Inner Diameter [mm]
119.6
BS Outer Diameter [mm]
112.2
BS Inner Diameter [mm]
108.2
BS thickness [mm]
2.0
Capillary Outer Diameter [mm]
4.76
hmax [mm]
102.68
w [mm]
11.1
S [mm]
1.1
Liner thickness [mm]
3.0
Width of liner [mm]
17.44 w a
hmax = Di,CBT - 2*0.7-2* *2.0 -2*s= Di,CBT *s
Di,BS = Di,CBT - 2*0.7-2*2.0 – 2*3.0= Di,CBT– 11.4
s= (Di,CBT / /2-0.7)(1-Cos[a])
w= (Di,CBT / /2-0.7)(Sin[a])
Width of liner: w - outer radius of Capillary = 22.2 mm mm
24/01/08
Energy deposition, LIUWG, Elena Wildner

19. Adding a liner along the Triplet
Recommendation:
3 mm W shield up to Q2
Continuous beam-screen and pipe, liner also between magnets
24/01/08
Energy deposition, LIUWG, Elena Wildner

20. Liner not covering entirely gap Q1-Q2
Liner 3mm W
No shielding, only BS and BP
24/01/08
Energy deposition, LIUWG, Elena Wildner

21. Liner not covering entirely gap Q1-Q2
Shielding like for “nominal”:
Peak due to 1.5 m “gap”
Shield needed between magnets
24/01/08
Energy deposition, LIUWG, Elena Wildner

22. Total heat load in magnets
24/01/08
Energy deposition, LIUWG, Elena Wildner

23. Energy deposition, LIUWG, Elena Wildner
Total heat load
Integration over 10 cm longitudinal (z) bins
Q Q2a Q2b Q3
24/01/08
Energy deposition, LIUWG, Elena Wildner

24. Between the Q1 and the Q2 magnets
Critical region, must be shielded:
Coil end
BPM aperture
1.4 cm stainless steel (checked case)
Nominal Layout
24/01/08
Energy deposition, LIUWG, Elena Wildner

25. Energy deposition, LIUWG, Elena Wildner
TAS opening
The TAS opening has been taken as 55 mm
24/01/08
Energy deposition, LIUWG, Elena Wildner

26. TAS, lateral and backwards scattering
Normalization (Lupgrade = 2.5 L0)
24/01/08
Energy deposition, LIUWG, Elena Wildner

27. TAS, mechanical considerations
Fluka - > Ansys
Luminosity: cm-2 s-1
TAS aperture: 55 cm
Total power in TAS: 300 W
Peak: 131 mW/cm3 ± 7%
24/01/08
Energy deposition, LIUWG, Elena Wildner

28. Energy deposition, LIUWG, Elena Wildner
Continuation
Choice of pipe sizes and absorbers for next iterations
Model of the region between Q1 and Q2a to be refined
3D field of coil ends, mechanical lengths
Corrector magnets to be implemented
Including D1, TAN, D2 and Q4
Detailed experimental pipes also before TAS
Mechanical analysis of the TAS
Detailed study on the beam particle distributions at the collisions
Ions
24/01/08
Energy deposition, LIUWG, Elena Wildner

29. Energy deposition, LIUWG, Elena Wildner
Conclusion
The beam-pipe and the beam-screen thicknesses are enlarged (aperture increase): decreases energy deposition in coils!
For good coil protection, we propose to add a 3 mm tungsten sheet (or equivalent) around the beam screen up to the entry of the second quadrupole.
We need to design detailed shielding in the region close to the beam-pipe between Q1 and Q2a, according to point 2 above (BPM, RF-conncetion, interconnects…)
24/01/08
Energy deposition, LIUWG, Elena Wildner

30. Energy deposition, LIUWG, Elena Wildner
Thanks to
Alessio Mereghetti
Joined team from 01/01/2008
R. Ostojic
V. Baglin
S. Fartoukh
M. Karppinen
S. Sgobba
L. Tavian
And others…
24/01/08
Energy deposition, LIUWG, Elena Wildner

31. Comparison, smaller aperture TAS
The smaller TAS aperture shields better the entrance of the first quad
The effect of 3 mm SS between magnets is important for peak in second quad
24/01/08
Energy deposition, LIUWG, Elena Wildner