NMR MANDHALA Magnetic Field Gradients

thingiverse

This is an updated version of the [NMR Mandhala Gradient](https://www.thingiverse.com/thing:3019735). This Thing features a modular design where multiple copies of the same magnet holder can be utilized to create linear gradients along various axes of an NMR MANDHALA. This was designed with an 8-cm inner diameter and holds four 1/2" x 1/4" x 1" magnets, specifically either [magnets with poles on tall, narrow sides](https://www.kjmagnetics.com/proddetail.asp?prod=BX048) or [magnets with poles on large faces](https://www.kjmagnetics.com/proddetail.asp?prod=SB8X04-IN). The measurements shown here use the N42 magnets provided in the links. The center two holders hold 8 magnets arranged to create a quadrupolar field, as described in an article by Peter Blümler ("Permanent Magnet System for MRI with Constant Gradient mechanically adjustable in Direction and Strength", Concepts in Magnetic Resonance Part B (Magnetic Resonance Engineering), No Vol. Number (2015), [DOI 10.1002/cmr.b.21320](https://www.researchgate.net/publication/282790159_Permanent_Magnet_System_for_MRI_with_Constant_Gradient_mechanically_adjustable_in_Direction_and_Strength?enrichId=rgreq-f91f6e789ad4ee8cb7a438bb543e20b8-XXX&enrichSource=Y292ZXJQYWdlOzI4Mjc5MDE1OTtBUzozNjMwNDE4ODQ1MjQ1NDRAMTQ2MzU2NzMzODUyMg%3D%3D&el=1_x_2&_esc=publicationCoverPdf)). The angle of the two gradient pieces relative to each other changes the gradient strength along the external homogeneous field provided by the NMR Mandhala. Maximum gradient strength is observed when all magnets are at 45-degree increments. We achieved a maximum gradient of ~11 Gauss/mm with this setup and the magnets given above. The outer two holders generate a linear gradient along the cylindrical axis by orienting the magnets such that one side adds to the homogeneous magnetic field created by the NMR Mandhala and the other side subtracts. One can control the strength of the gradient field by adjusting the separation between the two sides, with the maximum gradient we measured being ~5 Gauss/mm. This gradient is for use with an NMR MANDHALA which you can find here: https://www.thingiverse.com/thing:3012509 **NOTE: This model provides a tight fit, so we suggest using a scaling of 102% to make the gradients more easily adjustable when sliding them over the NMR MANDHALA.** This Thing was designed by Aaron Conover with the guidance of Merideth Frey, PhD, as part of the summer science research program 2019 at Sarah Lawrence College.