Variable Permanent Magnet Quadrupole

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

doi:10.1109/tasc.2006.873248

Cited by 18 publications

(12 citation statements)

References 2 publications

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“…/ SLAC collaboration for a final focus in a linear collider. The system consists of an inner hybrid ring with 8 sectors Halbach system and the outer ring being a pure 12-magnet Halbach structure rotating around the first one resulting in gradient variation from 17 T/m up to 120 T/m for a 230 mm magnetic length and 10 mm bore radius [45]. • A super hybrid quadrupole combining permanent magnetic material, coils and soft magnetic material has been built (see Figure 10) and tested for the new Brazilian Synchrotron Light Source (Sirius) [46].…”

Section: Variable Gradientmentioning

confidence: 99%

Permanent Magnet-Based Quadrupoles for Plasma Acceleration Sources

et al. 2019

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The laser plasma accelerator has shown a great promise where it uses plasma wakefields achieving gradients as high as GeV/cm. With such properties, one would be able to build much more compact accelerators, compared to the conventional RF ones, that could be used for a wide range of fundamental research and applied applications. However, the electron beam properties are quite different, in particular, the high divergence, leading to a significant growth of the emittance along the transport line. It is, thus, essential to mitigate it via a strong focusing of the electron beam to enable beam transport. High-gradient quadrupoles achieving a gradient greater than 100 T/m are key components for handling laser plasma accelerator beams. Permanent magnet technology can be used to build very compact quadrupoles capable of providing a very large gradient up to 500 T/m. We present different designs, modeled with a 3D magnetostatic code, of fixed and variable systems. We also review different quadrupoles that have already been built and one design is compared to measurements.

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Section: Variable Gradientmentioning

confidence: 99%

Permanent Magnet-Based Quadrupoles for Plasma Acceleration Sources

et al. 2019

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“…Because of the expertise gained in accelerator facilities, the use of permanent magnet quadrupoles (PMQs) appears to be slightly more robust in respect of APL. The required gradient level corresponds to values achieved for prototype systems [49,[56][57][58][59][60][61][62][63][64][65][66][67][68] rather than quadrupoles produced in large amounts. Moreover, special care has to be taken for the design of these PMQs, in particular for their multipolar content in order to minimize the beam spot size while avoiding chromatic aberration effects dominance [56,69].…”

Section: Introductionmentioning

confidence: 99%

Skew Quadrupole Effect of Laser Plasma Electron Beam Transport

et al. 2019

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Laser plasma acceleration (LPA) capable of providing femtosecond and GeV electron beams in cm scale distances brings a high interest for different applications, such as free electron laser and future colliders. Nevertheless, LPA high divergence and energy spread require an initial strong focus to mitigate the chromatic effects. The reliability, in particular with the pointing fluctuations, sets a real challenge for the control of the dispersion along the electron beam transport. We examine here how the magnetic defects of the first strong quadrupoles, in particular, the skew terms, can affect the brightness of the transported electron beam, in the case of the COXINEL transport line, designed for manipulating the electron beam properties for a free electron laser application. We also show that the higher the initial beam divergence, the larger the degradation. Experimentally, after having implemented a beam pointing alignment compensation method enabling us to adjust the position and dispersion independently, we demonstrate that the presence of non-negligible skew quadrupolar components induces a transversal spread and tilt of the beam, leading to an emittance growth and brightness reduction. We are able to reproduce the measurements with beam transport simulations using the measured electron beam parameters.

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“…As for introducing gradient tunability in PMQs, original designs were proposed and developed to provide a variable gradient, such as at SLAC / Fermilab collaboration [9]; at Kyoto U. / SLAC collaboration [10]; at STFC Daresbury Laboratory / CERN for the CLIC project [11].…”

Section: Introductionmentioning

confidence: 99%

Tunable high gradient quadrupoles for a laser plasma acceleration based FEL

Ghaith¹,

Kitégi²,

André³

et al. 2018

Nuclear Instruments and Methods in Physics Research Section A:

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Laser Plasma Acceleration (LPA) is capable of producing a GeV beam within a cm accelerating distance, but with a rather high initial divergence and large energy spread. COXINEL aims to demonstrate a compact Free Electron Laser using such a source, where a specific transport line with adequate elements is used, such as tunable high gradient quadrupoles for handling the divergence. An innovative permanent magnet based quadrupole (QUAPEVA) made of two quadrupoles superimposed capable of generating a gradient of 200 T/m is presented. The first quadrupole consists of magnets shaped as a ring and attaining a constant gradient of 155 T/m, and the second one made of four cylindrical magnets surrounding the ring and capable of rotating around their axis to achieve a gradient tunability of ± 46 T/m. Each tuning magnet is connected to a motor and controlled independently, enabling the gradient to be tuned with a rather good magnetic center stability (±10 µm) and without any field asymmetry. The measurements and field optimization of seven quadrupoles with different magnetic lengths are reported. A set of QUAPEVA triplet, installed at COXINEL, achieved good focusing and enabled beam based alignment.

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Variable Permanent Magnet Quadrupole

Cited by 18 publications

References 2 publications

Permanent Magnet-Based Quadrupoles for Plasma Acceleration Sources

Permanent Magnet-Based Quadrupoles for Plasma Acceleration Sources

Skew Quadrupole Effect of Laser Plasma Electron Beam Transport

Tunable high gradient quadrupoles for a laser plasma acceleration based FEL

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