Field Measurement System in Vacuum for a Cryogenic Permanent-Magnet Undulator at NSRRC

Yang, Chih‐Sheng; Chang, C. H.; Chen, Sei-Da; Lin, YuanYao; Hwang, Ching-Shiang

doi:10.1109/tasc.2016.2518488

Cited by 4 publications

(2 citation statements)

References 8 publications

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“…Moreover, the challenge of heating by synchrotron radiation has much improved compared to IVUs owing to the large cooling capability of the magnet configuration. At the present situation, rare earth-based CPMUs such as Nd 2 Fe 14 B and Pr 2 Fe 14 B are popular due to their higher coercivity and remanence properties at low (cryogenic) temperatures. ,− We believe the Tb 75 Fe 25 nanoglass could be the new class of material for the CPMU application.…”

Section: Resultsmentioning

confidence: 99%

Magnetic Tb₇₅Fe₂₅ Nanoglass for Cryogenic Permanent Magnet Undulator

Singh

Witte

Clemens

et al. 2020

ACS Appl. Nano Mater.

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In this paper, the magnetic properties of a nanostructured amorphous Tb 75 Fe 25 material, which is termed as nanoglass (NG), are reported. The nanoglass structure consists of two regions: a nanometer-sized glassy core (10−20 nm) and nanometers of glass−glass interfaces (∼1−2 nm). The nanoglass was prepared by inert gas condensation technique. The amorphous phase of this specific alloy composition is otherwise not synthesized by conventional rapid quenching techniques. The as-prepared NG was further treated by high-pressure torsion (HPT) to introduce deformation in the material. The Curie temperature was found to be around 200 K for the as-prepared and HPT-treated samples. The magnetic coercivity for the as-prepared and HPT samples was found to be about 4 T at 1.8 K. Furthermore, heat treatment of these two samples at 390 °C for 30 min was performed, which resulted in the crystallization of the amorphous alloys. X-ray diffraction patterns and Rietveld refinement reveal that cubic Fe 2 Tb and hexagonal Tb phases formed after heat treatment. It is substantiated that the high contents of Fe 2 Tb and Tb crystalline phases were precipitated after heat treatment for the HPT sample compared to the NG sample. There was no any pronounced texture effect observed after heat treatment in both cases. However, the coercivity of these samples decreased upon crystallization. The heattreated sample subjected to HPT was noted to have higher magnetization than the heat-treated NG. The above reported high coercivity (4 T) at 1.8 K could make the sample a suitable material for the application of cryogenic permanent magnet undulators (CPMUs).

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Section: Resultsmentioning

confidence: 99%

Magnetic Tb₇₅Fe₂₅ Nanoglass for Cryogenic Permanent Magnet Undulator

Singh

Witte

Clemens

et al. 2020

ACS Appl. Nano Mater.

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“…As the Hall sensor is cooled by nearby cold magnets, a temperaturedependent calibration of the Hall probe is necessary and all components of the system must be UHV compatible to avoid contamination. At SPring-8, TPS [24,56] and SLS in situ measurement systems based on laser-positioned components with a feedback system are used. The Hallprobe carrier is moved along a customized rail located in the vacuum chamber where the magnet arrays of the undulator are arranged, and the longitudinal position of the Hall probe is determined by a laser interferometer.…”

Section: In Situ Magnetic Measurement Systemmentioning

confidence: 99%

Challenges of in-vacuum and cryogenic permanent magnet undulator technologies

Huang

Kitamura

Yang

et al. 2017

Phys. Rev. Accel. Beams

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An in-vacuum undulator (IVU) provides a means to reach high-brilliance x rays in medium energy storage rings. The development of short period undulators with low phase errors creates the opportunity for an unprecedented brilliant light source in a storage ring. Since the spectral quality from cryogenic permanent magnet undulators (CPMUs) has surpassed that of IVUs, NdFeB or PrFeB CPMUs have been proposed for many new advanced storage rings to reach high brilliance x-ray photon beams. In a low emittance ring, not only the performance of the undulator but also the choice of the lattice functions are important design considerations. Optimum betatron functions and a zero-dispersion function shall be provided in the straight sections for IVU/CPMUs. In this paper, relevant factors and design issues for IVUs and CPMUs are discussed together with many technological challenges in short period undulators associated with beam induced-heat load, phase errors, and the deformation of support girders.

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