Field Quality and Magnetic Center Stability Achieved in a Variable Permanent Magnet Quadrupole for the Ilc

Iwashita, Yoshihisa; Mihara, T.; Kumada, М.; Spencer, C.M.

doi:10.1109/pac.2005.1590955

Cited by 3 publications

(2 citation statements)

References 2 publications

(3 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Common approaches involve the application of Hall probes to determine the field gradients or rotating coils to determine HOMFCs. This poses challenges in fabrication of the miniature coil and, in particular, suppressing vibrations during the measurement [12,13]. We present a method allowing the measurement of all relevant magnetic vector field components relying solely on a miniature Hall probe which can be applied to very small apertures at the precision required.…”

Section: Introductionmentioning

confidence: 99%

Characterization and tuning of ultrahigh gradient permanent magnet quadrupoles

Becker

Bußmann

Raith

et al. 2009

Phys. Rev. ST Accel. Beams

View full text Add to dashboard Cite

The application of quadrupole-devices with high field gradients and small apertures requires precise control over higher order multipole field components. We present a new scheme for performance control and tuning, which allows the illumination of most of the quadrupole-device aperture because of the reduction of higher order field components. Consequently, the size of the aperture can be minimized to match the beam size achieving field gradients of up to 500 T m −1 at good imaging quality. The characterization method based on a Hall probe measurement and a Fourier analysis was confirmed using the high quality electron beam at the Mainz Microtron MAMI.

show abstract

Section: Introductionmentioning

confidence: 99%

Characterization and tuning of ultrahigh gradient permanent magnet quadrupoles

Becker

Bußmann

Raith

et al. 2009

Phys. Rev. ST Accel. Beams

View full text Add to dashboard Cite

show abstract

“…As can be seen, there are four independent magnet assemblies that are retracted by motors. This is an alternative to rotating magnets of Volk [2], sliding magnets used by Kashikin [3], rotating rings built by Halbach [4] and the outer rotating ring slices built by Iwashita [5]. We measured magnetic performance with an air bearing rotating coil system, [6].…”

Section: Introductionmentioning

confidence: 99%

Performance of an Adjustable Strength Permanent Magnet Quadrupole

Gottschalk¹,

Kangas²,

Dehart³

et al.

Proceedings of the 2005 Particle Accelerator Conference

Self Cite

View full text Add to dashboard Cite

An adjustable strength permanent magnet quadrupole suitable for use in Next Linear Collider has been built and tested. The pole length is 42cm, aperture diameter 13mm, peak pole tip strength 1.03Tesla and peak integrated gradient * length (GL) is 68.7 Tesla. This paper describes measurements of strength, magnetic CL and field quality made using an air bearing rotating coil system. The magnetic CL stability during -20% strength adjustment proposed for beam based alignment was < 0.2 microns. Strength hysteresis was negligible. Thermal expansion of quadrupole and measurement parts caused a repeatable and easily compensated change in the vertical magnetic CL. Calibration procedures as well as CL measurements made over a wider tuning range of 100% to 20% in strength useful for a wide range of applications will be described. The impact of eddy currents in the steel poles on the magnetic field during strength adjustments will be reported.

show abstract

A Rotating Coil Apparatus With Sub-Micrometer Magnetic Center Measurement Stability

Spencer

Anderson

Jensen

et al. 2006

IEEE Trans. Appl. Supercond.

Self Cite

View full text Add to dashboard Cite

A rotating double coil apparatus has been designed and built so that the relative magnetic center change of a quadrupole is measured to an uncertainty smaller than 0.02 micrometers (=micron, µm) for a single measurement. Furthermore, repeated measurements over about an hour vary by less than 0.1 µm and by less than 1 µm for periods of 24 hrs or longer. Correlation analyses of long data runs show that the magnet center measurement is sensitive to mechanical effects, such as vibration and rotating part wear, as well as to environmental effects, such as temperature and relative humidity. Evolving apparatus design has minimized mechanical noise and environmental isolation has reduced the effects of the surrounding environment so that sub-micron level measurement uncertainties and micron level stability have been achieved for multi-day measurement periods. Apparatus design evolution will be described in detail and correlation data taken on water-cooled electromagnet and adjustable permanent quadrupoles, which are about 350 mm in overall length, will be shown. These quads were prototypes for the linac quads of the Next Linear Collider (NLC) that had to meet the requirement that their magnetic centers change less than 1 micron during a 20% change in field strength. Thus it was necessary to develop an apparatus that could track the magnetic center with a fraction of a micron uncertainty. To be published in IEEE Journal of Applied Superconductivity* Work supported by Department of Energy contract DE-AC02-76SF00515. 1Abstract-A rotating double coil apparatus has been designed and built so that the relative magnetic center change of a quadrupole is measured to an uncertainty smaller than 0.02 micrometers (=micron, µm) for a single measurement. Furthermore, repeated measurements over about an hour vary by less than 0.1 µm and by less than 1 µm for periods of 24 hrs or longer. Correlation analyses of long data runs show that the magnet center measurement is sensitive to mechanical effects, such as vibration and rotating part wear, as well as to environmental effects, such as temperature and relative humidity. Evolving apparatus design has minimized mechanical noise and environmental isolation has reduced the effects of the surrounding environment so that sub-micron level measurement uncertainties and micron level stability have been achieved for multi-day measurement periods. Apparatus design evolution will be described in detail and correlation data taken on water-cooled electromagnet and adjustable permanent quadrupoles, which are about 350 mm in overall length, will be shown. These quads were prototypes for the linac quads of the Next Linear Collider (NLC) that had to meet the requirement that their magnetic centers change less than 1 micron during a 20% change in field strength. Thus it was necessary to develop an apparatus that could track the magnetic center with a fraction of a micron uncertainty.

show abstract

Field Quality and Magnetic Center Stability Achieved in a Variable Permanent Magnet Quadrupole for the Ilc

Cited by 3 publications

References 2 publications

Characterization and tuning of ultrahigh gradient permanent magnet quadrupoles

Characterization and tuning of ultrahigh gradient permanent magnet quadrupoles

Performance of an Adjustable Strength Permanent Magnet Quadrupole

A Rotating Coil Apparatus With Sub-Micrometer Magnetic Center Measurement Stability

Contact Info

Product

Resources

About