1. HL LHC WP3 (magnets) TASK 2 ADVANCEMENT
CERN, 14th February 2012
WP3 – Task2 meeting
HL LHC WP3 (magnets) TASK 2 ADVANCEMENT
E. Todesco
CERN, Geneva Switzerland
With relevant inputs from colleagues
L. Bottura, O. Bruning, R. De Maria, S. Fartoukh, P. Ferracin, P. Fessia, B. Holzer, L. Rossi, G. Sabbi, …

2. FOREWORD Task 2: Nb3Sn Triplet (G. Sabbi)
Task 3: Separation dipoles (T. Nakamoto and P. Wanderer)
Task 4: Cooling (R. Van Weldereen)
Task 5: Other topics (J.-M. Rifflet) Q4
Nb-Ti triplet
Resistive magnets around IR4
In these slides I focus on the triplet, which has the highest degree of coupling between different WP and aspects – top priority
Meetings about other parts of the machine (D1, D2, Q4) will come soon
Partecipation: meetings are open and contributions are welcome

3. APERTURE OF THE TRIPLET
We can start analysing four lay outs given by WP2
Two technologies: Nb-Ti and Nb3Sn
Two apertures: 120 mm (present hardware) and 140 mm (more performance ?)
Aperture of D1 should be 10 mm larger than triplet
Two cases being analysed: 130 mm and 150 mm (Task 3)
First guess of four layouts up to D1 given by WP2 (S. Fartoukh, R. De Maria, B. Holzer)

4. PROOF OF TECHNOLOGY First priority is demonstrate Nb3Sn
Nb-Ti is the plan B, that will be also discussed in the preliminary design report
Independentely of 120/140 mm, the Nb3Sn technology will be proved on the ground of LARP on 120 mm
HQ and LHQ magnets will prove the technology by 2014
This will require a full qualification
Gradient, field quality, protection, heat transfer, …

5. THE PLAN
Plan: have a first estimate of the performance in each case by June
We should also provide time estimate for both 120 and 140 mm options, and rough estimate of costs
If we go to 140 mm we will need more time
We have to provide all the information to the project management in the first half of 2012
Decision on one aperture per Nb3Sn and one aperture for the Nb-Ti plan B in September 2012
Taken on the ground of performance, cost and schedule
Decision on technology will be possible only in

6. APERTURE OF THE TRIPLET
We can start analysing four lay outs given by WP2
Two technologies: Nb-Ti and Nb3Sn
Two apertures: 120 mm (present hardware) and 140 mm (more performance ?)
Aperture of D1 should be 10 mm larger than triplet
Two cases being analysed: 130 mm and 150 mm (Task 3)

7. THE CHOICE OF THE GRADIENT
Gradient has been selected on the following criteria
20% operational margin on the loadline
For Nb-Ti
120 mm: this is MQXC (15.1 mm LHC dipole cable, grading), gradient has been lowered to 118 T/m have 20% margin
140 mm: this is the sketch of MQXD cross-section presented by Glyn in November (15.1 mm LHC dipole cable, two layers) – 100 T/m
For Nb3Sn
120 mm: this is HQ (MQXE)
0.8 mm Ø strand, 35 strands (~15 mm width)
We lowered the jc at 12 T, 4.2 K from 3000 A/mm2 to 2600 A/mm2
We keep the same copper/non copper challenging ratio 1.13
This gives 170 T/m instead of 180 T/m as given previously
140 mm: this is MQXF [P. Ferracin]
0.8 mm Ø strand, 40 strands (~17 mm width - stress already top level in HQ)
Same choice of jc and same copper/non copper ratio 1.13
This gives 150 T/m

8. MILESTONE OF JUNE - 1
June 2011: Make a first iteration between all different aspects to understand if some parameters are clearly not good for integration in the LHC
First estimate of the powering scheme and magnet protection to understand if the copper content of the cable is too low
Possible feedback on strand (very urgent)
Have a first guess on maximum tolerable b6 at injection and compare to what obtained in HQ – have an idea of the FQ requirements on filament size
Find the maximum size of cold mass given by integration and solve the problems related to fringe field
Urgent for sizing of some tooling
Explore the option of no beam screen, in collaboration with AT-VSC

9. MILESTONE OF JUNE - 2 Plan of studies up to June 2011
Have a first estimate of energy deposition from WP10 and necessary shielding
Heat load versus margin
Radiation resistance
Heat load
This will feedback on avaliable aperture and performance
We should clarify the quench margin in continuous losses regime
Can we apply a larger quench limit for enhanced insulation?
More investigation for Nb3Sn limits
This will allow WP2 to estimate the performance of the four lay-outs given the free aperture (June-August)

10. MILESTONES OF JUNE - 3
Analysis of MQXC and HQ field quality to provide field quality tables to WP2
This depends on conductor for some multipoles
Estimation of the most dangerous multipoles and need of correctors
This could feed back on the lay-out where some space for correctors is already allocated
Have a first iteration on the interconnection lenghts with experts
This also could feed back on lay out
Analysis of tests of the existing hardware
Analysis of HQ test (February 2012 at CERN)
First test on MQXC (June 2012)
Heat transfer aspects