Status of BDS (QD0 and SD0) and PCL magnet studies for CLiC

1. Status of BDS (QD0 and SD0) and PCL magnet studies for CLiC M. Modena thanks for the contributions of: A.Aloev, A.Bartalesi, E. Solodko TE-MSC CLIC MDI Meeting, 24 May 2013

2. Outline: CLiC QD0 status CLiC SD0 Status Post Collision Line design status Conclusion

3. CLiC QD0 Status

4. CLiC QD0 Status Ashort prototype of the QD0 (3TeV layout) was then built at CERN in 2011-2012. Aim was to validate the conceptual Hybrid Magnet design proposed: PM blocks, Permendur core structure, Coils (low current density) for tunability. Prototype assembly completed at end of 2011. Two campaign of measurements were done in 2012 in two different configuration:- in January 2012: the QD0 equipped with Nd2Fe14Bblocks was measured with the Vibrating Wire System - in August 2012: the same type of measurement was done for the configuration with Sm2Co17 blocks .

5. CLiC QD0 Status Results of MEASUREDGradient (red dots) (extrapolated from the INTEGRATEDGRADIENT effectively measured), together with the COMPUTED Gradient (blue curves). • Measurements in the configuration with Sm2Co17 blocks are in very good agreement with the FEA computation. • With Nd2Fe14B blocks we see a difference of ~ -6% in the high gradient area. This could have 2 possible explanations: • The Permendur saturate at lower level than expected.  A FEA check with the real magnetization curve extracted from the raw material test report provided was done and this explanation seems excluded. • The quality (magnetization module and/or direction) of the Nd2Fe14B PM blocks is not the as expected.  We should get more indication of this possibility when the PM blocks measuring device (by Helmholtz coils) under purchasing by the Magnetic Measurements Section will be operational.

6. CLiC QD0 Status The histograms provides for both QD0 configurations the magnetic harmonic content (multipoles) versus the magnet powering ; upper graph for Nd2Fe14B, lower graph for Sm2Co17. For comparison: the first computed “permitted” mutipole at NI=5000A is (integrated) : b6=1.4 units (with NdFeB) and b6=0.7 units (with SmCo).

7. Outline: CLiC QD0 status CLiC SD0 Status Post Collision Line design status Conclusion

8. CLiC SD0 Status SDO can be also considered as a critical magnet as it is required with the stronger as possible gradient. Anyway, the magnet has less tight geometric boundary conditions being not placed inside the Detector.

9. CLiC SD0 Status αin αout PM “Easy direction” Rout PM block analysed parameters SD0 conceptual layout Optimizationprocess provides these values : αin = 18.9°αout = 8.4 ° Rout = 40 mm Magnet powering curve

10. CLiC SD0 Status Opt.3 S-grad 221 247 T/m2 Opt.1 S-grad 222 020 T/m2 Opt.2 S-grad 220 349 T/m2 Opt.4 S-grad 215 785 T/m2

11. CLiC SD0 Status The main requirements & boundary conditions for SD0 magnet are: To have the stronger as possible Gradient Tunability of ~ -20 % Minimized vibrations (magnet should be actively stabilized) Integration with the Post Collision vacuum pipe needed. Differently from QD0, compactness is less critical since the magnet will be placed outside the Detector and End-Cups, on the Accelerator Tunnel just at the border with the Experimental Hall. The proposed design should permit us to investigate the very precise assembly of several (4 or 5) longitudinal sections, each equipped with PM blocks. Key aspects: Manufacturing (with highest precision) of each Permendur sector and “C” shape return yokes Sorting of PM blocks Assembly of the sectors (substantial magnetic forces between blocks? PM blocks are very fragile!) Final alignment

12. Outline: CLiC QD0 status CLiC SD0 Status Post Collision Line design status Conclusion

13. Post Collision Line design status Aspect ratio x to y is set as 25 to 1

14. Post Collision Line design status

15. Post Collision Line design status

16. Post Collision Line design status

17. Post Collision Line design status A study was started on the possible “low consumption” alternative design for the big dipoles of the PCL.Key aspects: To provide a “low consumption” design solution RELIABILITY is a key word for these magnets: they will be placed in a dumping tunnel, area very radioactive and interventions must be MINIMIZED. The magnets could be subjected to high doses of radiation (new simulation on-going) Assumptions are the following: The most simple (and economic) cryogenic solution seems to take advantage of the cryo coolants available at the IP (Detector Solenoid). They will be at 4.5 K (LHe to the solenoid) or at 40-60 K (thermal shields). Distance from the PCL magnets: 35-100m (depending by the PCL versions considered). In these condition the cost of the cryogenic system will consist in the cryogenic transfer line and the valve box for the distribution to the magnets. Other solution are also considered. For the magnet COILS, several possibility are evaluated: “Classic SC” solution (i.e. NbTi) HTS (High Temperature Superconductor) (i.e. MgB2,YBCO, etc.) Each solution has advantages and disadvantages, trying to identify them to provide some first evaluations.. 1. Copper @ 293 K 2. NbTi @ 4.5 K 3. MgB2@ 20 K 4. YBCO @ 77 K “Active” coil cross-section comparison for some different solutions. Other aspect to be considered: Complexity/cost of the coil winding Complexity/cost of cryostats Operation Stability and radiation resistance 1. 2. 3. 4.

18. Conclusions: • QD0: nothing new since last meeting. We are waiting the Helmholtz magnetic measurement system to investigate the PM block quality. (A lot of the R&D and manufacturing key aspects will be studied with the SD0 procurement) • SD0: conceptual design is advancing well. Compare to the QD0 we have added more investigation and optimization towards field quality (more interactions with R. Tomas Garcia and Y. Levinsen that are now advancing with more detailed requirements for FF magnets in terms of Field quality i.e. multipoles requirements) • Post Collision Line magnets: waiting the approval of the new baseline, we are advancing with some alternative dipole conceptual design targeting: low consumption, reliability, resistance to radiation. • (NOTE: After a discussion with Rogelio of few days ago, a new subject line will be added for ECFA LC2013 WS of next week : “An hybrid QD0 for ILC ? (basic conceptual design)”. Unfortunately material was not ready for today presentation)