Two high field quality quadrupole magnets QF1FF and QD0FF are required for the final focus system of the ATF3. In this paper we focus on the design of the QF1FF magnet. The proposed design is a permanent magnet quadrupole (PMQ) with adjustable strength. Alternative solutions such as conventional electromagnetic quadrupole (EMQ) and a hybrid quadrupole (combination of permanent magnet and electromagnet) are also presented and briefly discussed.
An adjustable focusing system for a 2 MeV H- ion beam line based on permanent magnet quadrupoles
设计、建造并测试了一个基于四极永磁体（PMQ）的小型可调聚焦系统。使用有限元模拟实现PMQ模型，提供2.35 T的集成场梯度，最大场梯度为57 T/m。构造了一个原型，并测量了磁场，表现出良好的协议与模拟。粒子轨迹模拟提供了四极位置的初始值。相应地，在束线上构造并组装四个PMQ，然后调整它们的位置以在目标上获得（1.2 x 2.2）mm^2的最小束斑尺寸。本文介绍了一种用于外离子束的可调PMQ束线。基于市售NdFeB磁体的新颖紧凑设计为离子束应用提供了高度灵活性。
This paper presents a simulation study of a permanent magnet electron cyclotron resonance ion source (ECRIS) with a minimum-B quadrupole magnetic field topology. The magnetic field is made to conform to conventional ECRIS with $B_\textrm{min}/B_\textrm{ECR}$ of 0.67 and a last closed magnetic isosurface of 1.86$B_\textrm{ECR}$ at 10 GHz. The distribution of magnetic field gradients parallel to the field, affecting the electron heating efficiency, cover a range from 0 to 13 T/m, being similar to conventional ECRIS. Therefore it is expected that the novel ion source produces warm electrons and h…
Permanent magnet has a small and compact structure, is especially suitable for a narrow space. With the aid of soft iron, the magnetic field can be increased much more and the field uniformity can be well controlled. Most Permanent magnets have a symmetry structure; the soft iron can be selected as the float magnet pole to keep its constant scalar potential, and take roles as media to collect the direct flux from the permanent blocks, then release indirect flux in magnet aperture and to the nearby return yoke. This paper presents the magnetic flux method to design and fabricate a hybrid perman…
Several coil structures have been used in accelerator superconducting quadrupole magnets, and cos2θ quadrupole magnets are the most mature in theoretical research and engineering applications. However, the cos2θ quadrupole magnet has a complicated coil structure, especially at the end of the coil, which makes it difficult to apply strain-sensitive high-temperature superconductors. Racetrack quadrupole magnets are friendly to high-temperature superconductors. Field strength of iron-dominated racetrack magnets is limited by the magnetic saturation of the iron poles. Therefore, coil-dominated rac…
We derive a closed-form expression of the magnetic field of a finite-size current sheet and use it to calculate the field of permanent magnets, which are modeled through their surface current densities. We illustrate the method by determining the multipoles and the effective length due to fringe fields of a finite-length dipole constructed of magnetic cubes.
Due to the various applications of THz sources, we developed a pure permanent magnet (PPM) undulator with 8 periods and min/max values of gap equal to 15/25, to use at the end of our current 10 MeV linear accelerator (linac) in order to produce THz coherent radiation. We used RADIA for simulation and calculation of our magnet and B2E code for calculation of its radiation harmonics. After fabrication, we also measured the magnetic field via high precision Hall probes. Calculations and measurements are in good agreements. These calculations show that it is possible to reach photon energies from …
We describe a framework to assemble permanent-magnet cubes in 3D-printed frames to construct dipole, quadrupole, and solenoid magnets, whose field, in the absence of iron, can be calculated analytically in three spatial dimensions. Rotating closely spaced dipoles and quadrupoles in opposite directions allows us to adjust the integrated strength of a multipole. Contributions of unwanted harmonics are calculated and found to be moderate. We then combine multiple magnets to construct beam-line modules: chicane, triplet cell, and solenoid focusing system.
The first FCC-ee final focus quadrupole prototype has been designed, manufactured, assembled and tested at warm. The prototype is a single aperture quadrupole magnet of the CCT type. One edge of the magnet was designed with local multipole cancellation, whereas the other was left with the conventional design. An optimized rotating induction-coil sensor was used. A technique was developed to take into account field distortions due to the environment of the test and distinguish them from magnet effects, demonstrating an excellent field quality for the prototype.
