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Title: Variable Permanent Magnet Quadrupole

Abstract

A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.

Authors:
; ; ; ; ; ;
Publication Date:
Research Org.:
Stanford Linear Accelerator Center (SLAC)
Sponsoring Org.:
USDOE
OSTI Identifier:
907959
Report Number(s):
SLAC-PUB-12504
TRN: US0703604
DOE Contract Number:
AC02-76SF00515
Resource Type:
Journal Article
Resource Relation:
Journal Name: IEEE Trans.Appl.Supercond.16:224, 2006; Journal Volume: 16; Journal Issue: 224
Country of Publication:
United States
Language:
English
Subject:
43 PARTICLE ACCELERATORS; FABRICATION; IRON; LINEAR COLLIDERS; MAGNETS; PERMANENT MAGNETS; QUADRUPOLES; Accelerators,ACCPHY

Citation Formats

Mihara, T., Iwashita, Y., /Kyoto U., Kumada, M., /NIRS, Chiba, Spencer, C.M., and /SLAC. Variable Permanent Magnet Quadrupole. United States: N. p., 2007. Web.
Mihara, T., Iwashita, Y., /Kyoto U., Kumada, M., /NIRS, Chiba, Spencer, C.M., & /SLAC. Variable Permanent Magnet Quadrupole. United States.
Mihara, T., Iwashita, Y., /Kyoto U., Kumada, M., /NIRS, Chiba, Spencer, C.M., and /SLAC. Wed . "Variable Permanent Magnet Quadrupole". United States. doi:. https://www.osti.gov/servlets/purl/907959.
@article{osti_907959,
title = {Variable Permanent Magnet Quadrupole},
author = {Mihara, T. and Iwashita, Y. and /Kyoto U. and Kumada, M. and /NIRS, Chiba and Spencer, C.M. and /SLAC},
abstractNote = {A permanent magnet quadrupole (PMQ) is one of the candidates for the final focus lens in a linear collider. An over 120 T/m strong variable permanent magnet quadrupole is achieved by the introduction of saturated iron and a 'double ring structure'. A fabricated PMQ achieved 24 T integrated gradient with 20 mm bore diameter, 100 mm magnet diameter and 20 cm pole length. The strength of the PMQ is adjustable in 1.4 T steps, due to its 'double ring structure': the PMQ is split into two nested rings; the outer ring is sliced along the beam line into four parts and is rotated to change the strength. This paper describes the variable PMQ from fabrication to recent adjustments.},
doi = {},
journal = {IEEE Trans.Appl.Supercond.16:224, 2006},
number = 224,
volume = 16,
place = {United States},
year = {Wed May 23 00:00:00 EDT 2007},
month = {Wed May 23 00:00:00 EDT 2007}
}
  • A set of compact variable-field permanent-magnet quadrupoles have been designed, fabricated, and tested for use in the SSC linac matching section. The quadrupoles have 24 mm-diameter apertures and 40 mm-long poles. The hybrid (permanent-magnet and iron) design, uses a fixed core of magnet material (NdFeB) and iron (C-1006) surrounded by a rotating ring of the same magnet material and iron. The quadrupole gradient-length product can be smoothly varied from a minimum of 0.7 T up to a maximum of 4.3 T by a 90{degree} rotation of the outer ring of iron and magnet material.
  • The focusing system is an essential part of any ion microbeam system and focusing of MeV ion beams is generally accomplished using quadrupole lenses. There are two types of quadrupole lenses requiring the application of either voltage or current to provide the excitation, but there is also the possibility of utilizing lenses constructed from permanent magnets. All of these lens types have different advantages and disadvantages. Most microprobes employ electromagnetic quadrupoles for focusing, however electrostatic lenses have several advantages with respect to electromagnetic lenses, including significantly smaller size, no hysteresis effects, no heating, the utilization of highly stable voltage supplies,more » focusing which is independent of ion mass, and construction from industrial grade materials. The main advantage of the permanent magnetic lens is that it does not require the application of external power which can significantly reduce the overall lifetime cost. In this presentation, the short probe-forming systems comprised from all these types of quadrupole lenses are compared and the smallest beam spot size and appropriate optimal parameters of these probe-forming systems are determined.« less