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LER Magnets Major R&D Effort

LER Magnets Major R&D Effort. There are 2 distinct sets of magnets: Arc magnets covering ~ 26 km of accelerator circumference LER to LHC transfer line magnets covering total of ~ 1 km of beam path The VLHC low field magnet is proposed

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LER Magnets Major R&D Effort

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  1. LER Magnets Major R&D Effort • There are 2 distinct sets of magnets: • Arc magnets covering ~ 26 km of • accelerator circumference • LER to LHC transfer line magnets • covering total of ~ 1 km of beam • path • The VLHC low field magnet is proposed • as the base magnet for the LER arc. • The LER-LHC transfer line magnets are • viewed as new initiative in magnet design. The new injection scheme shows only the path from SPS to LER to LHC LARP LBL Meeting

  2. VLHC & LER Magnet Count VLHC: - 233 km accelerator ring - ~ 3200 main arc dipoles - ~ 466 km continued length of transmission line superconductor LER: - ~27 km accelerator ring - 1232 main arc dipoles - ~ 54 km continued length of transmission line superconductor LARP LBL Meeting

  3. Base Magnet of the LER Accelerator LER Main Arc Dipole Magnet • Magnet cross-section area: 26 cm (height) x 24 cm (width) Pole gap: 20 mm (?) • 1.6 Tesla field (nominal operation) (1.99 T for VLHC) • 0.6 Tesla (beam injection) (0.2 T for VLHC) • Alternating gradient: 12 m (64 m) • 20 mm magnet pole gap ( 25 mm ??) • Energized by 55 kA (87 kA for VLHC), single turn superconductor line • Coolant – supercritical helium (4.2 K, 3 bar, 60 g/s) • Warm beam pipe vacuum system- ante-chambers required We propose that LER is based on the VLHC low field, combined function dipole magnet LARP LBL Meeting

  4. LER Magnet Location in the LHC Tunnel • It fits easily in the space above the • LHC magnet • Vertical distance between LHC and • LER beams: 1350 mm • The holding brackets and the magnets • can be installed without disturbing the • LHC operations • The 4 K, 3 bar LHe can be tapped at • convenient locations from the QRL line • providing 1700 g/s flow LARP LBL Meeting

  5. LER Arc Dipole Magnet in LHC Tunnel Normal tunnel area Area with cryogenic feed tower LARP LBL Meeting

  6. VLHC Magnet and B-field Measuring Instrumentation • Magnet view (tangential coil side) Magnet view (Hall station side) LARP LBL Meeting

  7. Magnetic Measurements Gueorgui Velev, TUA07PO02 Probe: 15.2 mm dia. x 754.1 mm long Vespel (polyimide) used to form the probe (winding support) and bearings. Field Harmonics measured to: order 10 at 1.966 Tesla (collisions), and order 6 at 0.1 Tesla (injection) LARP LBL Meeting

  8. Magnetic Measurements • Quadrupole component is as designed; ~ -415 units, both at • injection and full field 1.966 T. • 102 element Hall Probe confirms • the +/- 4% gradient. • Sextupole component very small; • ~ few units, and no change from • injection to the full field 1.966 T. • The b4 – b10, and the a4 – a10 • also << 4 units, or << 0.04%. • LER magnet operates at 1.6 T !! LARP LBL Meeting

  9. Principle of the LER-LHC Beam Transfer • After the LER ring filling is complete, the pulsing magnets are turned • off as soon as the last proton bunch passed through them. LARP LBL Meeting

  10. Principle of LER-LHC beam transfer • Cryogenic support for fast pulsing magnets must sustain long-term • operations at 0.45 TeV, and a 100 second long ramping to 1.5 TeV LARP LBL Meeting

  11. LER-LHC Transfer Line Boundaries • Total length of ½ straight section: 260 m • Available free space between D1 and Q7: 176.5 m • To reproduce the LHC optics the LER-LHC transfer line magnets must reach the LER level of 1100 mm at the D2 LHC dipole (approximately 65 m from the end-face of D1) • A 336 T-m bending power is required to lift a 1.5 TeV beam by 1100 mm above the LHC nominal beam level, or on average ~5 T magnets are required for a 65 m beam path • For comparison, to bypass detectors by ~ 40 m in the straight sections of 260 m the transfer line magnets of ~50 T field would be needed LARP LBL Meeting

  12. LER-LHC Transfer Line Option 1 • No re-arrangement • of LHC, D1 magnet. • 4 vertical bends • preceded by a • horizontal bend to • provide enough • separation in the • first pair of vertical • dipole magnets for • the “cc” and “cw” • LER beams. • Three sets of fast • pulsing magnets are • needed! LARP LBL Meeting

  13. LER-LHC Transfer Line Option 2 • LHC D1 magnet is • moved a bit (or • shortened) to make • a space for a (5 m?) • LER single bore • dipole magnet. • Only one set of fast • Pulsing magnets is • needed! LARP LBL Meeting

  14. An Example of Possible Vertical Bend Magnet Arrangement LARP LBL Meeting

  15. LER-LHC Transfer Line Magnets • In order to accomplish the LER-LHC beam transfer the beam • line must consists primarily of three type of dipole magnets: • - 2 T range, normal conducting, fast pulsing, single bore dipole to • enforce the LER beam circulation in the LHC • - 2 T range, normal conducting, single bore dipole operating with • the LHC LER beam pipe separation of no less than 75 mm • (40 mm beam pipe and ~ 30 mm for the magnet yoke) • - 7-8 T, superconducting, two-bore, 1m long vertical dipole to pass • the LER beam through most of the 1.35 m vertical separation LARP LBL Meeting

  16. Fast Pulsing Magnets From Martin N. Wilson, Superconducting Magnets, ISBN 0 19 854810 9 (Pbk), 1997 • - For 3 microseconds current decay time, L < 1 uH, so the magnet length is • typically < 1 m, and the conductor spacing 40-60 mm. • - For B field in 2 T range, the conductor current is in the range of 100 kA. • - Magnet operating < 25 K (lowest resistance of Cu) is the only option. LARP LBL Meeting

  17. Fast Pulsing LER-LHC Transfer Line Magnets • Horizontal bend of both LER beams. Vertical bend of the LER beams, • B-field shaped by laminations, B-field shaped by conductors, • conductors are LHe cooled. conductors are LHe cooled. 40 mm gap, 1.5 T max @ 90 kA Pulsed or continual operation 60 mm gap, 2.0 T max @ 67 kA pulsed or continual operation. CERN operated WC 0.6 T magnet @ 29 kA LARP LBL Meeting

  18. LER-LHC Transfer Line Magnets • A vertically bending magnet – • for horizontally separated LER • and LHC beams. • Continual or fast pulsing • operations. • Laminations are used to contain • magnetic flux, and to minimize • fringe field at the LHC beam. LARP LBL Meeting

  19. Fast Pulsing Magnet Power Supply • For I = 90 kA and L =1 uH of the magnet system, the voltage drop is 30 kV at • 3 microsecond of current decay time. Lowering the operating temperature of • the power supply switcher cells to 25 K will eliminate need for the HTS leads. LARP LBL Meeting

  20. LER Major Magnet R&D for FY07 • Dipole, 2T range, single bore (30-50 mm), 0.8 m long, dc, • 3 microsecond turn-off time, LHe cooled condcutors: • (a) magnetic field shaped by conductor • (b) magnetic field shaped by Silicon Steel tape core • Goal for FY07: magnetic and mechanical/cryo design • 2. A 100 kA dc power supply with 3 microsecond turn-off time: • (a) switcher cells operating below 100 K, possibly • down to 25 K • (b) fast transformer/heater to turn-off the current • (c) superconducting dump resistor to expend magnetic • energy • Goal for FY07: research and preliminary design LARP LBL Meeting

  21. LER Major Magnet R&D for FY07 • 3. Two-bore (40 mm), high field (7-8 T) vertically bending magnet: • set of short (0.8m) 12-15 magnets arranged into a single cryostat • Goal for FY07: magnetic and mechanical/cryo design • 4. VLHC combined function magnet, 1.6 T, 25 and 30 mm gaps: • Goal for FY07: magnetic design LARP LBL Meeting

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