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Permanent magnet array (PMA) is a popular option to provide the main magnetic field in a dedicated portable magnetic resonance imaging (MRI) system because it does not need power or a cooling system and has a much stronger field strength…

Medical Physics · Physics 2024-11-07 Ting-Ou Liang , MinXuan Xu , Wenwei Yu , Shao Ying Huang

We report on the development of a microfabricated atomic magnetic gradiometer based on optical spectroscopy of alkali atoms in the vapor phase. The gradiometer, which operates in the spin-exchange relaxation free regime, has a length of 60…

Instrumentation and Detectors · Physics 2017-02-14 Dong Sheng , Abigail R. Perry , Sean P. Krzyzewski , Shawn Geller , John Kitching , Svenja Knappe

The design of a magnetic field source that can switch from a high field to a low field configuration by rotation by $90^\circ$ of a set of iron pieces is investigated using topology optimization. A Halbach cylinder is considered as the…

Instrumentation and Detectors · Physics 2019-01-11 R. Bjørk , A. R. Insinga

Adaptable, low-cost, coils designed by carefully selecting the arrangements and geometries of simple primitive units are used to generate magnetic fields for diverse applications. These extend from magnetic resonance and fundamental physics…

We present a laboratory electromagnet capable of generating magnetic fields up to $\pm$0.48T, specifically designed as a perpendicular flux source for thin film samples in an ambient environment. The magnet features a 250mm diameter clear…

Instrumentation and Detectors · Physics 2021-01-07 A. P. Petrović , B. H. M. Smit , K. L. Fong , B. Satywali , X. Y. Tee , C. Panagopoulos

By utilizing the quadratic dependency of the interferometry phase on time, the Hannover Very Long Baseline Atom Interferometer facility (VLBAI) aims for sub nm/s$^2$ gravity measurement sensitivity. With its 10 m vertical baseline, VLBAI…

Purpose: Conventional MRI is relying on the assumption of the magnetic field being homogeneous in direction and amplitude. However, with the growing interest in portable, affordable point-of-care MRI systems, these assumptions do not…

Medical Physics · Physics 2026-02-17 Fabian Bschorr , Thomas Hüfken , Tobias Lobmeyer , Volker Rasche

High pressure Nuclear Magnetic Resonance (NMR) is known to uncover behavior of matter at extreme conditions. However, significant maintenance demands, space requirements and high costs of superconducting magnets render its application…

A general scheme for increasing the difference in magnetic flux density between a high and a low magnetic field region by removing unnecessary magnet material is presented. This is important in, e.g., magnetic refrigeration where magnet…

Instrumentation and Detectors · Physics 2014-10-13 R. Bjørk , C. R. H. Bahl , A. Smith , N. Pryds

Very-low-field MRIs are becoming increasingly popular due to their portability and adaptability to different environments. They are being successfully used for various clinical applications, leading to a paradigm shift in the way imaging…

Computational Engineering, Finance, and Science · Computer Science 2025-12-24 Umberto Zanovello , Alessandro Arduino , Vittorio Basso , Luca Zilberti , Alessandro Sola , Andrea Agosto , Luca Toso , Oriano Bottauscio

We present a Scanning Hall Probe Microscope operating in ambient conditions. One of the unique features of this microscope is the use of the same stepper motors for both sample positioning as well as scanning, which makes it possible to…

Mesoscale and Nanoscale Physics · Physics 2017-12-12 Gorky Shaw , R. B. G. Kramer , N Dempsey , K Hasselbach

Spin-exchange relaxation free alkali-metal magnetometers typically operate in the regime of high optical density, presenting challenges for simple and efficient optical pumping and detection. We describe a high-sensitivity Rb magnetometer…

Atomic Physics · Physics 2009-03-16 V. Shah , M. V. Romalis

A magnet designed for use in a magnetic refrigeration device is presented. The magnet is designed by applying two general schemes for improving a magnet design to a concentric Halbach cylinder magnet design and dimensioning and segmenting…

Instrumentation and Detectors · Physics 2014-10-09 R. Bjørk , C. R. H. Bahl , A. Smith , D. V. Christensen , N. Pryds

We present a method of optical magnetometry with parts-per-billion resolution that is able to detect biomagnetic signals generated from the human brain and heart in Earth's ambient environment. Our magnetically silent sensors measure the…

Medical Physics · Physics 2020-07-29 M. E. Limes , E. L. Foley , T. W. Kornack , S. Caliga , S. McBride , A. Braun , W. Lee , V. G. Lucivero , M. V. Romalis

An atomic magnetometer operated with elliptically polarized light is investigated theoretically and experimentally. To explore the potential of this magnetometric configuration, the analytical form of the outgoing signal is derived.…

Atomic Physics · Physics 2020-01-08 Shengran Su , Guoyi Zhang , Xin Bi , Xiang He , Wenqiang Zheng , Qiang Lin

Purpose: To demonstrate in-vivo imaging with a low-cost, low-field MRI scanner built and operated in Africa, and to show how systematic hardware and software improvements can mitigate the main operational limitations encountered in…

Access to Magnetic Resonance Imaging system assembly knowledge can be expanded by leveraging open-source hardware and software, simplified installation requirements, and collaborative training initiatives. To this end, we conducted a…

We optimized designs of permanent magnet systems to study the effect of magnetic nanoparticles on cell cultures in microslide channels. This produced two designs, one of which is based on a large cylindrical magnet that applies a uniform…

Biological Physics · Physics 2024-01-04 Leon Abelmann , Eunheui Gwag , Baeckkyoung Sung

Presently, Magnetic Resonance Imaging (MRI) magnets must deliver excellent magnetic field (B0) uniformity to achieve optimum image quality. Long magnets can satisfy the homogeneity requirements but require considerable superconducting…

Medical Physics · Physics 2024-02-15 Marina Manso Jimeno , John Thomas Vaughan , Sairam Geethanath

We describe a novel pulsed magnetic gradiometer based on the optical interference of sidebands generated using two spatially separated alkali vapor cells. The sidebands are produced with high efficiency using parametric frequency conversion…

Atomic Physics · Physics 2021-11-25 Kaleb Campbell , Ying-Ju Wang , Igor Savukov , Peter Schwindt , Yuan-Yu Jau , Vishal Shah