1. Compact & Low Consumption Magnet Design Workshop for Future Linear and Circular Colliders Geneva, November 26-28, 2014 Saving opportunities in accelerator magnets Davide Tommasini

2. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014 Saving …what ? Materialinvestment cost, smaller coils Electricity running cost, larger coils, Sc, PMs Infrastructurespace, supports, services «Optimum» J~3-5 A/mm 2 for resistive magnets we tend associating saving to … cost we tend associating cost to … money cost/money … for what ? What is a cost if 1 t of oil? Politically, we should probably associate a higher cost for energy than the commercial one but now … let’s focus on technical matters

3. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014 DescriptionProCons Permanent MagnetsNo powering Compactness Reliability Fixed field (unless trimmeable) Large magnets limited in field Lower current densityPower consumption Easier cooling Reliability especially if air cooled Size Investment cost Pulsed operationPower consumptionComplexity (power converter + operation) Not always possible SuperconductingAbsence of Joule losses Enables higher field intensities Complexity (everything) Investment cost Maintenance (whole system) Dynamic behaviour Smaller magnet borePower consumption Magnet cost & size Complex beam optics design/operation Combined magnetCompactness Infrastructure cost Limited in field Field quality Power consumption Use of high saturation materials Compactness Weight Running cost Investment cost

4. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014

6. Sextupoles for AsacusaCleaning dipole for n-TOF Quadrupole for LINAC 4 QD0 for CLIC

7. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014 The PS East Experimental Area houses five beam lines, derived from the 24 GeV/c proton beam from the Proton Synchrotron accelerator (PS)

8. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014 EAST AREA CONSUMPTION AFTER CONSOLIDATION PULSED MODEDC MODE Energy in MWhPrice in kCHFEnergy in MWhPrice in kCHF Total magnet electrical consumption 55728.39 128464 Water cooling electrical consumption 794.01 29466 Air cooling electrical consumption 261.343122 Total electricity consumption66233.710 853551.8 Total cooling fluid 6.2 101.5 TOTAL energy cost 40 kCHF 653 kCHF TypeEstimated Price in kCHF per magnetNumber of magnets after consolidationTotal cost per family in kCHF MDX206120 M100702140 M2001005500 Q100505250 Q200704280 Q74401 Total231.3 MCHF

9. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014

10. Using superconducting magnets when you could use normal conducting ones? The conclusion of this study was that the investment cost of the two option was comparable, but the operation cost of the warm solution is twice that of the superrferric solution. A similar study performed for SIS 100 (G.Moritz, ASC 2002) arrived at a similar conclusion (yearly operation cost 2.05 ME for resistive magnets, 0.9 ME/year for superferric magnets). Electrical consumption (MW)NCSC Main Magnets7.50 RF22 Other systems33 Cryoplant01.3 Water cooling station1.20.4 Ventilation0.5 Climatisation0.4 Total consumption14.67.6

11. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014 A superconducting magnet is often more complicated If the magnet is cycled, dynamic losses increase complication Let’s consider overlapping situations: Required field amplitudes within the range of 2T Required dynamic rates up to few T/s Indicative threshold for considering superconducting magnets Single units, DC operated : 100 KW Single units, AC operated : 1 MW Synchrotrons : 5-10 MW If we had to redo the CERN synchrotrons today we would: certainly do the PSB NC probably do the PS NC certainly do the SPS Sc (probably at higher energy)

12. Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014

13. 1.the present cost of electricity does not motivate for increasing magnet sizes to reduce the current density below 2-3 A/mm 2. 2.Where possible it is economically advantageous to use pulsed or permanent magnets. 3.The use of (expensive) high saturation materials may allow saving weight. 4.Superconducting magnets may be the definitive route to save power, weight and money when a trimmeable magnetic field is needed. Their use is limited by their complexity and accessibility. 5.When a trimmeable magnetic field is not needed, the use of permanent magnets shall be explored first, with more vigour and initiative than usually done in our field.

14. Thank you for your attention