1. f James T Volk June 20021 Permanent Magnets for Linear Colliders James T Volk Fermilab

2. f James T Volk June 20022 People already working on Permanent magnets SLAC Seung Rhee, Cherrill Spencer, Jim Spencer SLAC Magnetic Measurement Group Scott Anderson, Zack Wolf Fermilab Magnetic Measurement Joe DiMarco LBNL Jose Alonso, Jin-Young Jung

3. f James T Volk June 20023 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

4. f James T Volk June 20024 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

5. f James T Volk June 20025 Permanent Magnets at SLAC SLC 72 Sextupoles made of Sm 1 Co 5 SLC final focus 4 Octupoles made of SM 2 Co 17 PEPII two normal and two skew Quadrupoles made of SM 2 Co 17 All small Halbach style magnets

6. f James T Volk June 20026 Fermilab Recycler 8 GeV transfer line: 750 m long from booster to MI Gradient Mirror gradientSextupole Recycler: 8 GeV anti proton storage ring Over 500 gradient, quadrupole, and sextupole permanent magnets Temperature stable Fields adjusted to within 5 parts in 10 4 Harmonics 1 part in 10 4 Vertical and Horizontal tune within 0.001 of design

7. f James T Volk June 20027 Representative Dipole Technologies From Kem Robinson LBNL

8. f James T Volk June 20028 Quads for NLC Quad

9. f James T Volk June 20029 NLC LINAC Quad Specs

10. f James T Volk June 200210 Wedge Quad Rods rotate to adjust field Pole Magnets Tuning Rods Wedge Magnets Flux Return Poles

11. f James T Volk June 200211 NLC adjustable quad on SSW stand Quad Stretched wire stages

12. f James T Volk June 200212 Wedge Quad Rod Turning Mechanism Tuning Rod May 2002 James T Volk Pin slides in slot turning rod

13. f James T Volk June 200213 Center shifts wedge quad

14. f James T Volk June 200214 SLAC Rotating Coil Data X max 2.5  Y max 4.5 

15. f James T Volk June 200215 Counter Rotating Quadrupole

16. f James T Volk June 200216 Counter Rotating Quad Data

17. f James T Volk June 200217 Results

18. f James T Volk June 200218 Issues Improve center stability Time stability Temperature stability Motor controls Optimize Design New Designs

19. f James T Volk June 200219 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

20. f James T Volk June 200220 TOSCA model of ¼ Neo quad with a steel end plate

21. f James T Volk June 200221 Radiation Damage Summary

22. f James T Volk June 200222 Radiation Damage in SM Cobalt

23. f James T Volk June 200223 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:N32ZLower 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

24. f James T Volk June 200224 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!

25. f James T Volk June 200225 Radiation Test Dipole Design PM Material 2 inch gap

26. f James T Volk June 200226 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

27. f James T Volk June 200227 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!