Wir schaffen Wissen – heute für morgen Paul Scherrer Institut Alexander Gabard The PSI Experience: a Theory of Evolution or „the quest for compactness“ Paul Scherrer Institut, ATK division PSI, 27. November 2014 Outline • PSI History • Proton facility (HIPA) • PROSCAN • SLS • SwissFEL • Conclusion • Outlook A very brief history of PSI • 1960: creation of EIR in Würenlingen • 1960: physics department at ETH decides to build a particle accelerator • 1968: location found (across the river from the EIR), creation of SIN • 1974: 590 MeV Cyclotron in operation (High Intensity Proton Accelerator HIPA) • 1989: EIR and SIN merged into PSI • 1996: SINQ • 2001: SLS • 2007: PROSCAN cancer treatment facility • 2010: SwissFEL 250 MeV Injector test facility (SITF) • 2016: SwissFEL 6 GeV machine • 2020: SLS 2.0? PSI, 27. November 2014 Seite 3 Facilities SwissFEL HIPA SITF PROSCAN 18-22 MW SLS PSI, 27. November 2014 Seite 4 HIPA 1200 1200 650 800 1200 400 1000 1200 1200 3600 1050 numbers indicate magnet current in Amps; most other main beamline magnets run at 400-500 Amps PSI, 27. November 2014 Seite 5 Considerations? PSI, 27. November 2014 Seite 6 Considerations? • „In the old days, we would just order what the physicists wanted“ PSI, 27. November 2014 Seite 7 Considerations? Cost considerations: • Discussion of initial investment vs. Operating costs • Base: seven years, including a 50% factor for quads • Stick to internal standards in terms of PS: 50 A, 200 A, 500 A • Main constraint: space PSI, 27. November 2014 Seite 8 Ring accelerator sector magnets Main goals in 1969: • Pion and Muon production (Targets) • 500 MeV energy (590 MeV in the end) • 100 µA beam current (today: 2400 achieved, 3000 in preparation) Specs: • Gap: 55 to 86 mm • Conductor 19.5 sq by Ø11.5mm, 80 turns • Current: 1000 A, power 60 kW / magnet • Field: 1.9 Tesla PSI, 27. November 2014 Seite 9 Sector Magnets Bulletin Oerlikon, January 1969 PSI, 27. November 2014 Seite 10 Short Quads Main constraint: Space? Mean Lifetime • • • μ− : 2 μs π+, π - : 26 ns πo : 84 as -> reduce length of flight path Aperture: 260 mm Iron length: 270 mm PSI, 27. November 2014 Seite 11 PROSCAN PSI, 27. November 2014 Seite 12 PROSCAN COMET 250 MeV 3.9 Tesla SC 160A Ø 4m 90 tons Magnet dimensions mostly defined by beam optics • Degrader shifts energy 70-230 MeV, creates divergence (99% loss at 70 MeV) wide poles, large gaps • Degrader shifts with Δt = 80ms all components downstream must follow laminated, low field [1,2] • Gantry 2: large 90 degree dipole due to upstream sweeping [3] PSI, 27. November 2014 Seite 13 PROSCAN dipoles 480mm Dimensions 2 x 1 x 0.5 m Mass: 12 t Gap: 65mm B=1T PSI, 27. November 2014 Seite 14 PROSCAN quads • • • • • PSI, 27. November 2014 Aperture 100 mm G = 16.25 T/m Pole Tip Field = 0.65 T 750 kg 9 kW Seite 15 Gantry 2 90 degree dipole PSI, 27.11.2014 Seite 16 Gantry 2 90 degree dipole 46 tons Gap 150 mm 500 A 85 kW B=1.56 T ? Integrated Vacuum chamber PSI, 27.11.2014 Seite 17 SLS – first electron machine @ PSI Aperture 60 mm G = 23 T/m 380 / 420 kg 2.5 kW Aperture 68 mm G = 742 T/m2 400 kg 1.4 kW Gap 41 mm B = 1.4 T 2700 kg 10 kW • Watercooling used as feature for temperature stability (ΔT = 10C, low current density) • Aperture defined by beam optics • • • • • PSI, 27. November 2014 Sextupoles with correctors; correctors operate at 50 Hz «reasonably fast» beam based alignment Three different lengths for each quad profile Two different dipole lengths Cycling after PS failure much faster laminated magnets Seite 18 Context : The Swiss Free Electron Laser- SwissFEL Two FEL Beamlines: Hard X-ray Beamline Aramis: SASE FEL (1 – 7 Å), tuning mostly by energy (2016) Soft X-ray Beamline Athos: SASE FEL (7 – 70 Å), seeded FEL (10 – 70 Å), tuning by gap and energy (2018) One injector , two bunch compressor chicanes, three linacs for a beam energy up to 5.8 GeV Status and Milestones Injector and booster test facility (250 MeV) in operation; Facility will be moved to SwissFEL in 2015 End 2014: Building ready; Magnet installation planned from beginning 2015 Mid 2017: Routine operation of the Aramis line; End of 2018: Athos line installation 162 small aperture quadrupoles S.Sanfilippo / M.Buzio 20th IMEKO TC4 International Symposium – Benevento (Italy) Sep 15-17. 2014 SwissFEL Power supply costs: CHF PSI, 27. November 2014 20k 5k Seite 20 Considerations - SwissFEL • Reduce operating costs • Reduce magnet size • Reduce machine size and length combined function magnets) • Eliminate water cooling (and thus flow induced vibrations) Consequences: • Small aperture with relatively large iron body to increase airflow • Combined function: good cooling eight coils instead of twelve large stray field • Fast feedback – up to 1 kHz correction laminated magnets, low core loss iron, some parts non-metallic • High operating temperature; temperature drift • Increased mechanical precision requirements PSI, 27. November 2014 Seite 21 Considerations - SwissFEL Aperture 45 mm G = 1.5 T/m 11 kg 5W PSI, 27. November 2014 Aperture 45 mm G = 25 T/m 94 kg 3.2 kW Aperture 12 mm G = 50 T/m 32 kg 40 W Aperture 22 mm G = 50 T/m 180 kg 870 W Seite 22 Considerations - SwissFEL Integrated X/Y steerers Laminated yoke Room for ventilation Non-magnetic parts (1kHz fast feedback) Air cooled coils PSI, 27. November 2014 Seite 23 Considerations - SwissFEL 12º C Magnet temperature [deg. C] Magnet thermal expansion vs. time (QFD) 11 µm PSI, 27. November 2014 8 hrs Time [hrs] Magnet vertical expansion [µm] 11 µm Magnet thermal expansion vs. temp. (QFF) Magnet vertical expansion [µm] Magnet vertical expansion [µm] Magnet vertical expansion [µm] Magnet thermal expansion vs. temp. (QFD) 7 µm 11º C Magnet temperature [deg. C] Magnet thermal expansion vs. time (QFF) [4] 7 µm 6 hrs Time [hrs] Seite 24 Considerations - SwissFEL Operating temperature? PSI, 27. November 2014 Seite 25 • Considerations - SwissFEL • QFB Design: 10 A max. current • Depicted above: 20 A current • PSI, • 27. November 2014 • Seite 26 Measuring small magnets • For SwissFEL: 150+ quads • Mechanical deviations forbidden harmonics • Small aperture small rotating coil strong restraints regarding pick-up coil positioning • Long, thin rotating coil: coil warps asymmetric rotation inside quad artificial dipole harmonics • Compensation measurements required to eliminate artificial harmonics; but lack of room for compensation coils so reduced number of turns, which limits coil sensitivity • Solutions: PCB coils (max. 500mm); In-Situ calibration; hybrid measurement systems like vibrating, rotating wire (CERN) • Conclusion: Compact magnets are harder to measure accurately • see presentation of Marco Buzio PSI, 27. November 2014 Seite 27 Considerations - SwissFEL Conclusion: the SwissFEL Magnets are PSI‘s idea of the current state of the art in terms of Compact and Low Consumption Magnets PSI, 27. November 2014 Seite 28 Outlook In technical terms: • Watercooled – outdated • Air cooled resistive – works but has its limits • Laminated (ramping, fast feedback, flexibility in magnet length) • Superconducting magnets • Permanent magnets? • Push development of measurement systems to increase precision For PSI: • SLS 2.0 • SC Gantry PSI, 27. November 2014 Seite 29 PSI‘s theory of evolution PSI, 27. November 2014 Seite 30 Thank you for your attention PSI, 27. November 2014 Seite 31 References [1] M. Negrazus et al., "Eddy Current Reduction in Fast Ramped Bending Magnets"; Proceedings of the 19th International Conference on Magnet Technology, MT-19, IEEE Transactions on Applied Superconductivity, Vol. 16, No. 2, pp. 228-230, June 2006. [2] M. Negrazus et al., "The Fast Ramped Bending Magnets for the Gantry 2 at PSI"; Proceedings of the 20th International Conference on Magnet Technology MT-20, IEEE Transactions on Applied Superconductivity, Vol. 18 No.2, pp. 869-898, June 2008. [3] A.Gabard et al., “Magnetic Measurements and Commissioning of the Fast Rapmed 90º Bending Magnet in the PROSCAN Gantry 2 Project at PSI”; Proceedings of the 21 st International Conference on Magnet Technology, MT-21, IEEE Transactions on Applied Superconductivity, Vol. 20 No. 3, pp. 794-797, June 2010. [4] R.Ganter et al., “Status of SwissFEL Undulator Lines; Proceedings of FEL 2013“, New York, August 2013, pp. 263-266 PSI, 27. November 2014 Seite 32
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