270 likes | 382 Views
Permanent Magnets for Linear Colliders. James T Volk Fermilab. People already working on Permanent magnets. LBNL Jose Alonso, Jin-Young Jung. SLAC Seung Rhee, Cherrill Spencer, Jim Spencer. SLAC Magnetic Measurement Group Scott Anderson, Zack Wolf. Fermilab Magnetic Measurement.
E N D
Permanent Magnets forLinear Colliders James T Volk Fermilab James T Volk June 2002
People already working on Permanent magnets LBNL Jose Alonso, Jin-Young Jung SLAC Seung Rhee, Cherrill Spencer, Jim Spencer SLAC Magnetic Measurement Group Scott Anderson, Zack Wolf Fermilab Magnetic Measurement Joe DiMarco James T Volk June 2002
Why Permanent Magnets • No Power Supplies • No Cables • No Water Cooling • No Operating Expense • Temperature stable • Time stable • Easy to Assemble • Can be in-expensive depending on field required and material chosen James T Volk June 2002
Where can they be used • Fixed energy transport lines • Bending • Focusing • Injection or extraction • Storage Rings • Final Focus near or inside of detectors • Quadrupoles in the NLC • Damping Rings James T Volk June 2002
Permanent Magnets at SLAC • SLC 72 Sextupoles made of Sm1 Co5 • SLC final focus 4 Octupoles made of SM2 Co17 • PEPII two normal and two skew Quadrupoles made of SM2 Co17 • All small Halbach style magnets James T Volk June 2002
Fermilab Recycler 8 GeV transfer line: 750 m long from booster to MI Gradient • Recycler: 8 GeV anti proton storage ring • Over 500 gradient, quadrupole, and sextupole permanent magnets Temperature stable Fields adjusted to within 5 parts in 104 Harmonics 1 part in 104 Sextupole Mirror gradient Vertical and Horizontal tune within 0.001 of design James T Volk June 2002
Representative Dipole Technologies From Kem Robinson LBNL James T Volk June 2002
Quads for NLC Quad Quad James T Volk June 2002
NLC LINAC Quad Specs James T Volk June 2002
Wedge QuadRods rotate to adjust field Poles Pole Magnets Wedge Magnets Tuning Rods Flux Return James T Volk June 2002
NLC adjustable quad on SSW stand Stretched wire stages Quad James T Volk June 2002
Wedge Quad Rod Turning Mechanism Tuning Rod Pin slides in slot turning rod May 2002 James T Volk James T Volk June 2002
Center shifts wedge quad James T Volk June 2002
SLAC Rotating Coil Data X max 2.5 m Y max 4.5 m James T Volk June 2002
Counter Rotating Quadrupole James T Volk June 2002
Counter Rotating Quad Data James T Volk June 2002
Results James T Volk June 2002
Issues • Improve center stability • Time stability • Temperature stability • Motor controls • Optimize Design • New Designs James T Volk June 2002
LBNL & SLAC work on designing magnets (PMs and EMs) for the damping rings • Main Damping Ring lattices have been published with detailed requirements on all magnets • Have 2-D model of DR quadrupoles and transport line dipoles. The Nd Iron style magnets are of reasonable size • Investigated the Nd Iron quads, with rotating rods to generate the +/-10% adjustability, in more detail to see if they could meet all the requirements. • Jin-Young Jung (LBNL) used TOSCA to make a 3-D model of damping ring magnets James T Volk June 2002
TOSCA model of ¼ Neo quad with a steel end plate James T Volk June 2002
Radiation Damage Summary James T Volk June 2002
Radiation Damage in SM Cobalt James T Volk June 2002
Radiation-Induced Demagnetization(Japanese experience with 200 MeV protons) • Material Type has large impact Red: N48 High Br (1.4T) Low Hc (1.15 MA/m) Blue: N32Z Lower Br (1.14 T) Higher Hc (2.5 MA/m) • Material Shape has large impact (All samples are discs 10 mm dia) Circle: thickness = 2 mm (Pc = 0.5) Triangle: thickness = 4 mm (Pc = 1.0) Square: thickness = 7 mm (Pc = 2.0) - Higher Permeance coefficient increases resistance (x 10) • SmCo is much more resistant than NdFeB James T Volk June 2002
Radiation damage tests Variety of particles p, n, d, , e used ND-Iron Radiation damage not well determined Energy is low Kev to Mev range No consistent dosimetry used All done on free bricks not magnets! James T Volk June 2002
Radiation Test Dipole Design PM Material 2 inch gap PM Material James T Volk June 2002
Radiation Damage Issues • Identify Radiation fields where PM could be used • Obtain consistent data on magnetic field loss • Determine Magnetic Field loss as a function of • Type of radiation • Amount of radiation • Dependence on Hc and other magnet parameters • Dependence on manufacturer James T Volk June 2002
Conclusions • There is plenty of work to do with permanent magnets • Improve quads for the LINAC • Investigate other applications • Measure effect of radiation on various magnet material • Plenty of real work to do! James T Volk June 2002