1. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE1 Carlos A. Martins Instituto Superior Técnico (IST) – Technical University of Lisbon Centre for Innovation in Electrical and Energy Engineering (CIEEE) (formerly a section leader at CERN in the power converters group)

2. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE2 1.- Introduction on Power Supplies for particle accelerators - Classifications; 2.- Main issues to be considered in the design - Load Regime (topology), Precision, EMC compliance, Remote controls, Safety, Reliability/maintenability; 3.- Examples of magnet power supplies (CERN case study) - Of the shelf; - Custom made; 4.- Solid state klystron modulators for proton Linac´s 5.- Potential contributions from CIEEE / IST 6.- Conclusions

3. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE3 1.- Power Supplies for magnets - beam bending magnets; - beam correction magnets (steerers, quadrupoles, solenoids, sextupoles, etc.); - beam kicking magnets (septa, kickers); - special purpose (gamma transition, beam scope meters, etc.); 2.- Power Supplies for RF tubes - Tetrodes for RF generators in particle sources; - Klystron / IOT modulators for accelerating structures; Classification based on the load type

4. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE 4 Classification based on load regime Regime modeEnergy efficiency Cost / Volume Voltage (V), Current (I) waveforms Physics Machine 1.- DC mode 1-quadrant ( V + ; I +); LowHigh DC Synchrotrons Or Superconducting machines 2.- Function tracking mode 1-quadrant ( V + ; I +); 2-quadrants ( V +/- ; I +); 4-quadrants ( V +/- ; I +/-) Medium Normal conducting Fast Cycling Synchrotrons Or Transfer Line Bending magnets 3.- Pulsed mode 2-quadrants ( V +/- ; I +) HighestLowest Normal conducting LINACs and Transfer Lines t(s) 0 V, I t(s) 0 V, I t(ms) 0 V, I

5. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE5 1.Load regime (power) selection of topology (DC, function tracking, pulsed); nº of quadrants; Cabling and AC feeders; Cooling (air natural or forced; water); 2.Precision Stability (over one year ?, one day ?, half an hour ?); Reproducibility (pulse to pulse); Precision budget should be established together with beam dynamics specialists; Impact mostly from the choice of DCCTs (magnets supplies) or HV voltage dividers (RF tube supplies); These complex sensor devices are manufactured by very few companies (i.e. Danfysik, Hitec, North Star,...); 3. EMC compliance All power supplies should be compliant with international standards in terms of EMC emissions and immunity. Specific testing campaigns shall be planned and executed during prototyping and production acceptance; The guarantee that all systems (power supplies, instrumentation electronics,...) will perform correctly once integrated together in the machine

6. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE6 4.Remote Control System Selection of the fieldbus (WorldFIP?, ScienceFIP?, Ethernet?, WhiteRabbit?,...); Interface with the low-level controller part in the power supplies; Physical layout of the controller (single board?, cassette?, chassis?,...); Should be UNIQUE to all power supplies in the physics complex; Online monitoring, diagnosis and post mortem facilities; 5.Reliability and maintainability MTBF – Mean Time Between Failures (should be ~ 10 years, individually; if total power supplies = 1000 -> Total MTBF = 4 days); Lifetime should be ~20 years by design (ageing of components like capacitors, obsolescence, thermal cycling of semiconductors must be taken into account); MTTR – Mean Time to Repair (should be ~1 hour); Spare parts and spare power supplies policy (shall be foreseen from the very early stage of the project and included in call for tenders; inventory data-base created and updated); 6. Safety Fire risks (special cables?); Access for operation (Grounding equipment, capacitor discharge systems,...); Presence of oil in HV equipments (leakage retainers, fire prevention systems,...);

7. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE7 Danfysik Delta Elektronika Heinzinger FUG Technix High Voltage DC; Capacitor Chargers High Voltage DC; Medium Voltage DC; Capacitor Chargers Low voltage DC Low voltage DC; High Voltage DC; Capacitor Chargers

8. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE8 Developed for CERN PS Consolidation program PS Gamma Transition (500A pk, +/-6kV pk ) PS Pole Face Windings (+/-250A, +/-1.2kV) PS Pole Face Windings (+/-1600A, +/-600V) Function tracking type

9. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE9 CERN Linac2, PS Booster & PS Consolidation programs Also foreseen for Linac4 19,3U 7 ms 20A Linac2 & PSB TL Steerers (Pulsed: 20A pk, 600V pk, 5ms/5 Hz) Pulsed type voltage current 1 ms 300A 500V Power crate 19, 6U Electronics crate 19, 3U Linac2 & Linac3 Quads (Pulsed: 300A pk, 1kV pk, 1ms/5 Hz) Septa current PS injection / extraction Septa (Pulsed: 20kA pk, 300V pk, 0.6ms/1 Hz)

10. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE10 Typical Requirements Klystron power supply - Pulse width:~2 ms - Flat-top duration~1.5 ms - Precision at flat-top:< 1% - HF ripple at flat-top:< 0.1% - Repetition rate:2..50 Hz - Nominal voltage:~120 kV - Nominal current:~20..100 A - Nominal power (peak):~10 MW - Rise/fall times (99% / 1%):~10% of Pulse width - Maximum energy in case of arc:< 20 J Pulse width Rise timeFall time time Flat-top V Shape of High Voltage Pulses Collector (GND) Cathode (-) ~ hundred kV + -

11. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE11 Also foreseen for: - Project X @ Fermilab; - XFEL @ Desy; The FERMILAB / DESY type modulator (Without pulse transformer) Simplified schematic, with pulse transformer 120 kV, 140A, 2.3ms, 10 Hz

12. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE12 CERN Prototype (3-MeV Test Stand & Linac4) Simplified schematics 100 kV, 20A, 0.8ms, 2 Hz

13. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE13 SLAC Prototype Also a candidate for: - ILC; 115 kV, 135A, 1.5 ms, 5 Hz

14. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE14 Oak Ridge (SNS) modulators 140 kV, 70A, 1.6ms, 60 Hz (9.8 MWpk, 940 kWav) AC/DC input converter not shown

15. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE15 J-PARC modulators

16. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE16 1.Carry on Studies for the Technical Design Report and Work-Package Description Define main parameters, types and quantities for each application (in close collaboration with magnets team (magnet power supplies), RF team (klystron modulators) and beam dynamics team; Propose topologies/references taking into account the market availability; Define remote control system (in close collaboration with controls people); Estimate costs, volumes, auxiliary requirements (water cooling, AC electrical feeders, AC and DC cables); Planning; 2.Studies on Klystron Modulator Topologies Evaluate in detail the existing topologies; Propose the most suited topology for ESS (High power, High repetition ratio); Study in detail the adopted topology by simulation and small scale prototyping (~same voltage, ~10% of rated power); Synergy with CERN possible; Or alternatively (consulting): Participate in writing-up of technical specifications and test protocols; Evaluate commercial offers; follow-up of contracting milestones; participate in the testing campaign; 3.Realization of prototypes for custom made power supplies 4.Write-up technical specifications, test protocols. Follow-up of construction and validation On Power Supplies and Klystron Modulators:

17. Towards a Portuguese participation in the ESS project, 29 th Jan. 2010, Lisbon Carlos Martins – IST / CIEEE17 1.Power Supplies and Klystron Modulators are key technologies in accelerators Klystron modulators are probably the second most challenging sub-systems in high duty-cycle Linacs, just after accelerating structures… – Maurizio Vretenar, CERN Linac4 Project Leader; Very few European and Worldwide companies are able to develop and produce such specific equipment (particularly for klystron modulators) 2.Of the Shelf versus customized solutions should be carefully evaluated At least 2 solid companies (preferably 3) shall be able to provide the same or equivalent Of the shelf product (double source), to avoid risks of bankruptcy, monopoles in the long term future; The project team shall have a word to say on the selection of the topology (technology); Do not delegate entirely this responsibility to companies; Careful about functional specifications (technical specifications would be preferable…): - Too much freedom given to companies on turn-key solutions may put the whole project dependent on a single company in terms of delays, performance, long term reliability and maintainability; 3.Close follow-up of companies technical activities is essential Single contracts (not a long term based commercial exchange); Companies main objective: Profit (which is perfectly fair and honourable); Project main objectives: Systems ready on time according to specifications; Reliable and maintainable in long term (20 years); Be sure to get all documentation, knowledge and relevant information about the equipment; Before placing a contract:- cross-check all parameters and technical details with the other partners of the project; Be sure the specifications are clear and cover all pertinent technical details. Companies will challenge you on this capability…