compact & low consumption magnet design workshop for future linear and circular colliders...
TRANSCRIPT
Compact & Low Consumption Magnet Design Workshop for Future Linear and Circular CollidersGeneva, November 26-28, 2014
Saving opportunities in accelerator magnets
Davide Tommasini
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Saving … what ?Material investment cost, smaller coilsElectricity running cost, larger coils, Sc, PMsInfrastructure space, supports, services
«Optimum» J~3-5 A/mm2 for resistive magnets
we tend associating saving to … costwe 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
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Saving opportunitiesDescription Pro Cons
Permanent Magnets No poweringCompactnessReliability
Fixed field (unless trimmeable)Large magnets limited in field
Lower current density Power consumptionEasier coolingReliability especially if air cooled
SizeInvestment cost
Pulsed operation Power consumption Complexity (power converter + operation)Not always possible
Superconducting Absence of Joule lossesEnables higher field intensities
Complexity (everything)Investment costMaintenance (whole system)Dynamic behaviour
Smaller magnet bore Power consumptionMagnet cost & size
Complex beam optics design/operation
Combined magnet Compactness Infrastructure cost
Limited in fieldField qualityPower consumption
Use of high saturationmaterials
CompactnessWeightRunning cost
Investment cost
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Impact of operation time
1 2 3 4 5 6 7 8 9 100
200
400
600
0.0
2.0
4.0
6.0
8.0
10.0
12.0
14.0
16.0Example for a 1.5 T dipole, L= 2m, gap=80 mm
Magnet costTotal cost (5000 h)Total cost (50000 h)Total cost (100000 h)Total mass
Current density (A/mm2)
Cost
(kCH
F)
Mag
net w
eigh
t (to
ns)
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Saving … space
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Permanent Magnets
Sextupoles for Asacusa Cleaning dipole for n-TOF
Quadrupole for LINAC 4 QD0 for CLIC
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Pulsed OperationThe PS East Experimental Area houses five beam lines, derived from the 24 GeV/c proton beam from the Proton Synchrotron accelerator (PS)
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Pulsed OperationEAST AREA CONSUMPTION AFTER CONSOLIDATION
PULSED MODE DC MODE Energy in MWh Price in kCHF Energy in MWh Price in kCHF Total magnet electrical consumption 557 28.3 9 128 464Water cooling electrical consumption 79 4.0 1 294 66Air cooling electrical consumption 26 1.3 431 22
Total electricity consumption 662 33.7 10 853 551.8
Total cooling fluid 6.2 101.5
TOTAL energy cost 40 kCHF 653 kCHF Type
Estimated Price in kCHF per magnet
Number of magnets after consolidation
Total cost per family in kCHF
MDX 20 6 120M100 70 2 140M200 100 5 500Q100 50 5 250Q200 70 4 280Q74 40 1 40
Total 23 1.3 MCHF
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Superconducting Magnets
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Superconducting MagnetsUsing 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) NC SC
Main Magnets 7.5 0
RF 2 2
Other systems 3 3
Cryoplant 0 1.3
Water cooling station 1.2 0.4
Ventilation 0.5 0.5
Climatisation 0.4 0.4
Total consumption 14.6 7.6
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Superconducting or Normal?
• 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
Here, the job can be done by Sc or by Normal magnets
Indicative threshold for considering superconducting magnetsSingle units, DC operated : 100 KWSingle units, AC operated : 1 MWSynchrotrons : 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)
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Use of high saturation materials
0
5
10
15
20
25
30
35
0 1000 2000 3000 4000 5000 6000 7000 8000 9000 10000
H (Oersteds)
B (k
G)
1010 Steel (MTID=0)
Decarburized iron (MTID=-1)
Vanadium permendur (STI, MTID=-2)
Vanadium permendur (GE, MTID=-3)
Compact & Low Consumption Magnet Design Workshop Davide Tommasini Geneva, November 26-28, 2014
Conclusion1. the present cost of electricity does not motivate for increasing magnet sizes to reduce
the current density below 2-3 A/mm2.
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.
Thank you for your attention