1. CERN, 11th November 2011
Hi-lumi meeting
HL-LHC: INITIAL WORKFLOW BETWEEN MAGNETS, BEAM DYNAMICS, AND ENERGY DEPOSITION
E. Todesco
CERN, Geneva Switzerland
With relevant inputs from colleagues
M. Bajko, A. Ballarino, O. Bruning, R. De Maria, F. Cerutti, L. Rossi, …

2. TASKS OF THE WORKPACKAGE
Task 2. IR quadrupoles in Nb3Sn [G. L. Sabbi , LBNL]
Task 3. Separation and recombination dipoles [T. Nakamoto KEK , P. Wanderer BNL]
Task 4. Cooling [ R. van Weldeeren, CERN]
Task 5. Other topics [J. M. Rifflet, CEA]
Large aperture Q4
Nb-Ti option for the inner triplet
Resistive quadrupoles in IR3 and IR7

3. LAY-OUT FOR THE LUMINOSITY UPGRADE
Issue: different workpackages need info from others, creating loops
Green: beam dynamics WP2
Blue: magnet WP3
Red: energy deposition WP3
Yellow: powering WP3
Length
Protection
Coil aperture
Magnet design:
Gradient,
Current,
Yoke
Stored energy
Cooling
Lay-out
Beam aperture
Powering
Field quality
Heat load, Shielding
Correctors
Crossing angle
Beam screen
& cold bore
Beta*

4. LAY-OUT FOR THE LUMINOSITY UPGRADE
Issue: different workpackages need info from others, creating loops
Green: beam dynamics WP2
Blue: magnet WP3
Red: energy deposition WP3
Yellow: powering WP3
Length
Protection
Coil aperture
Magnet design:
Gradient,
Current,
Yoke
Stored energy
Cooling
Lay-out
Beam aperture
Powering
Field quality
Heat load, Shielding
Correctors
Crossing angle
Beam screen
& cold bore
Beta*

5. LAY-OUT FOR THE LUMINOSITY UPGRADE
Issue: different workpackages need info from others, creating loops
Green: beam dynamics WP2
Blue: magnet WP3
Red: energy deposition WP3
Yellow: powering WP3
Length
Protection
Coil aperture
Magnet design:
Gradient,
Current,
Yoke
Stored energy
Cooling
Lay-out
Beam aperture
Powering
Field quality
Heat load, Shielding
Correctors
Crossing angle
Beam screen
& cold bore
Beta*

6. LAY-OUT FOR THE LUMINOSITY UPGRADE
Issue: different workpackages need info from others, creating loops
Green: beam dynamics WP2
Blue: magnet WP3
Red: energy deposition
Yellow: powering
Length
Protection
Coil aperture
Magnet design:
Gradient,
Current,
Yoke
Stored energy
Cooling
Lay-out
Beam aperture
Powering
Field quality
Heat load, Shielding
Correctors
Crossing angle
Beam screen
& cold bore
Beta*

7. LAY-OUT FOR THE LUMINOSITY UPGRADE
We have to cut the loop
Proposal: we start from coil aperture, and then we estimate performance
Iteration of the loop may be necessary
Crossing angle input and output
Cooling should iterate with magnet design
Field quality and need of correctors may iterate with lay out
A first sketch should be available as soon as possible (end of the year)
Many WP just need an estimate, not the final numbers
But they cannot wait for final design otherwise is too late …

8. MAGNETS FOR THE INNER TRIPLET
Today we have two pieces of hardware at 120 mm
MQXC – 120 mm aperture Nb-Ti quadrupole (ex-phase I)
Coil fabricated - short model being assembled
Test for spring 2012
HQ – 120 mm aperture Nb3Sn quadrupole
(LARP)
Magnet assembled and tested ta 4.2 K a few times
Second set of coils being assembled
To be tested also at CERN
I would call this MQXD

9. MAGNETS FOR THE INNER TRIPLET
Indication from beam dynamics:
Larger apertures can give larger performance
Drawbacks with larger apertures:
Longer & larger magnets, larger stored energy, difficult protection
Larger fringe field
Longer times for new design and tooling (2 years?)
We will study 140 mm aperture cases
MQXE – 140 mm aperture Nb-Ti quadrupole
MQXF – 140 mm aperture Nb3Sn quadrupole
In summer 2012 we will have
Evaluation of gain in performance from 120 to 140 mm
Understand if 140 mm is possible
Management will decide

10. MQXF – CONCEPTUAL design
Inputs: Nb3Sn 140 mm aperture and 20% margin
Options [see P. Ferracin talk]
Cable width: 15 mm as in HQ or 17 mm to reduce stress
Timeline for first sketch of conceptual design:
Outputs (report)
Operational current, gradient
Stresses, conceptual mechanical structure
Choice of the cable
Field maps, coil cross-section, field quality
Used by
Energy deposition (field maps)
Protection and powering (cable, current, stored energy, inductance)
Cooling (margin, cross-section)
Optics (lay-out, field quality)

11. MQXE – CONCEPTUAL design
Inputs: Nb-Ti 140 mm aperture, 20% margin
Options [see G. Kirby talk]
LHC dipole cable (graded or not?)
Timeline for first sketch of conceptual design:
Outputs (report)
Operational current, gradient
Stress, conceptual mechanical structure as in MQXC
Field map, coil cross-section, field quality
Used by
Energy deposition (field maps)
Protection and powering (cable, current, stored energy, inductance)
Cooling (margin, cross-section)
Optics (lay-out, field quality)

12. MQXC FOR 5×1034 cm-2 s-1, 3000 fb-1
Born in the Phase I upgrade framework
2.5×1034 cm-2 s-1, 700 fb-1  5×1034 cm-2 s-1, 3000 fb-1
Gradient increased from 120 T/m (2008) up to 127 T/m
Now the loadline margin is 11%, temperature margin only of 1.2 K
We propose to go back 20% margin, lower gradient Timeline:
Outputs (web)
New operational current, gradients, margins, field map
Used by
Energy deposition (field maps)
Protection and powering (cable features, current, stored energy, inductance)
Cooling (margin, cross-section)
Optics (lay-out, field quality)

13. MBXD/E – CONCEPTUAL design
MBXD/E: wide & single aperture, Nb-Ti separation dipole
[see T. Nakamoto talk]
Inputs: 130 mm and 150 mm apertures – 30% margin
Options
LHC (30 mm) or MQXA cables (20 mm)
Timeline:
Outputs (report)
Operational current, gradient (both options)
Stress, conceptual mechanical structure (both options)
Choice of the cable - Field map, cross-section
Used by
Energy deposition (field maps)
Protection (cable features, current, stored energy, inductance)
Cooling (margin, cross-section) - Optics

14. LAY OUTS Definition of four lay-outs Inputs Timeline: January 2012
120 mm quad (Nb3Sn MWXD or Nb-Ti MQXC) plus 130 mm MBXD
140 mm quad (Nb3Sn MWXF or Nb-Ti MQXE) plus 150 mm MBXE
Inputs
Gradients (from magnet design)
Hypothesis on correctors, and interconnection lengths
Timeline: January 2012
Outputs (web)
Magnet lengths
Used by
Energy deposition (lay-outs)
Protection and powering (total stored energy and inductance)

15. PROTECTION Inputs Options Timeline: from January 2012 to December 2012
Operational fields and gradients
Cable properties
Magnet lengths
Options
Heaters, dump resistors, powering scheme
Timeline: from January 2012 to December 2012
Outputs (report)
First proposal of protection for the two lay outs
Identify bottlenecks that could make one lay out impossible
Used by
Magnet design (iteration on copper/no copper ratio in cable)

16. COOLING
Design of the yoke should include from the beginning cooling requirements (as for MQXC)
Inputs
Magnet cross-section
Heat loads
Temperature margins
Options
1.9 or 4.2 K
Timeline: from January 2012 to December 2012
Outputs (report)
Cooling scheme
Structure of the iron
Used by
Magnet design (iteration on iron and/or margin if needed)

17. OPEN ISSUES TO BE CLARIFIED SOON
Limit in the energy deposition:
4.3 mW/cm3 used for Nb-Ti, based on very old estimates
Review this limit and understand how much set for Nb3Sn
Maximal fringe field acceptable in the tunnel
With larger apertures we will have mT on the cryostat
Cold mass size limited
Shielding needed?
Radiation resistance of all materials
We need to launch tests for MGy

18. TENTATIVE SCHEDULE FOR NEXT 12 MONTHS
Tentative date: have in August 2012 a decision on 120/140 mm
Hypotheses on technology: Nb3Sn is the baseline, Nb-Ti the plan B
Final decision at the end of the study