Micro-coils for MR spectroscopy by deep silicon etching

Syms, R.R.A.; Ahmad, M.M.; Young, I. R.; Gilderdale, D. J.; Collins, David; Leach, Martin O.

doi:10.1088/1742-6596/15/1/003

Cited by 2 publications

(1 citation statement)

References 12 publications

(10 reference statements)

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“…Coils may be passivated with SU-8, an epoxy-based resist [6] with excellent mechanical properties. Recently, we have shown that coils formed this way have sufficient performance for both imaging and spectroscopy [7]. Here, we show how the approach may be used to form needle-shaped coils.…”

Section: Introductionmentioning

confidence: 95%

Needle Micro-Coils for MRS

Syms

Ahmad²,

Young³

et al.

19th IEEE International Conference on Micro Electro Mechanical Systems

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A process for batch fabrication of low-cost needle-shaped microcoils for magnetic resonance spectroscopy (MRS) is demonstrated. The conductors are embedded inside a cross-section designed to avoid the signal cancellation that can occur with a completely immersed coil. Conductors are fabricated on oxidised silicon substrates by electroplating metals inside a deep resist mould, and then capped with a thick layer of epoxy resist. Throughwafer deep reactive ion etching is used to define needle shapes, and die separation is carried out by snap-out. Prototype coils are robust, and sharp enough to puncture model samples of fruit. At 63.8 MHz, Q-factors on Si substrates are comparable to those obtained on glass, and resonators based on single-turn coils have Q-factors of 14. Total immersion 1 H MR imaging and spectroscopy are demonstrated in a 1.5 T field using tomato fruits.

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Section: Introductionmentioning

confidence: 95%

Needle Micro-Coils for MRS

Syms

Ahmad²,

Young³

et al.

19th IEEE International Conference on Micro Electro Mechanical Systems

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Mems Nuclear Magnetic Resonance Microcoil

Ghasemi

Bahrami

2017

Biomed. Eng. Appl. Basis Commun.

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NMR is one of the important analytic tools which is used to obtain certain information such as metabolic concentrations in neural or muscular tissues. In some other important applications such as proton decoupling, it is necessary to design NMR transmitters/receivers capable of operating at multiple frequencies, while maintaining a good performance at each frequency. In this work, a new nuclear magnetic resonance (NMR) receiver microcoil based on MEMS technology is proposed. The designed structure uses MEMS microswitches with low contact resistance and NMR-based actuation mechanism. The proposed device can detect carbon (13C), proton (1H), and phosphorus (31p) nucleus with larmor frequencies of 96.36[Formula: see text]MHz, 383[Formula: see text]MHz, and 155.11[Formula: see text]MHz at 9 T magnetic field, respectively. The designed microcoil achieves three important goals: (1) Getting high SNR, high Q and high filling factor which are key parameters in NMR performance, by changing number of turns. (2) Turning into the array of microcoils to obtain better SNR. (3) Turning into two or three microcoils inside of each other for simultaneous detection. The MEMS microswitch in this paper uses static magnetic field of the NMR for its operation ([Formula: see text]T) which simplifies the switch mechanism. This switch is small (150[Formula: see text][Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]50[Formula: see text][Formula: see text]m[Formula: see text][Formula: see text][Formula: see text]6[Formula: see text][Formula: see text]m), scattering parameters of 43.2[Formula: see text]db isolation and 0.0059 insertion loss and maximum displacement of 2.03[Formula: see text][Formula: see text]m due to the magnetostatic actuation. In this work, the models and investigations are conducted using finite element simulations in COMSOL Multiphysics. The switch scattering parameters are obtained by HFSS 12.0.

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Micro-coils for MR spectroscopy by deep silicon etching

Cited by 2 publications

References 12 publications

Needle Micro-Coils for MRS

Needle Micro-Coils for MRS

Mems Nuclear Magnetic Resonance Microcoil

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