NLC Ring-Tuned, Permanent Magnet-Based Halbach Quadrupole

Introduction:

Significant operational cost savings may be obtained by use of permanent magnet quadrupoles in main accelerators of a linear collider (LC). At Fermi National Laboratory, needed tunability of quadrupole gradient has been demonstrated in prototypes while simultaneously holding the magnetic center constant to less than 10 microns, as required for suppression of emittance growth in the LC linac.

Until now, work has not progressed to investigate one of the more promising designs, the ring-tuned Halbach (patent number 4,549,155) quadrupole. Fermilab completed the design for the prototype and production of all necessary parts. Currently at the Particle Beam Physics Laboratory at UCLA, assembly, preliminary testing, initial tuning and 3-D modeling (using the code RADIA) of the ring-tuned pmq are under way at our magnet testing facilities. It will then be sent to Fermilab for further analysis in the FNAL and SLAC magnet test facilities. A combination of prototyping, testing and computational analysis will allow optimization of the Halbach quadrupole for LC linac focusing use.

Visit the Pacific Century Enterprise website to learn more about the type of magnets being used.

Ring-Tuned PMQ Parameters:

Item	Value
Magnet gradient	approx. 200 T/m
Effective length	180 mm
Adjustment range	+0 to -20%
Center stability	1 micron < over range of adjustment
Material	Neodymium

Current Progress

Daily updates on progress of assembly and testing of the NLC PMQ

Mechanical Design Drawings:

This section contains preliminary designs of the ring-tuned mechanical system, along with representations of the magnetic field lines.

Photo Gallery:

The photo gallery contains many random pictures of the actual pieces of the ring-tuned pmq along with photos of the devices used in measurements and testing.

Documentation:

This section contains the documentation relating to and describing the ring-tuned pmq.

Preliminary Magnet Data:

Here you will find excel spreadsheets containing some preliminary and analyzed data compiled from measuring various aspects of the ring of magnets in the ring-tuned pmq.