Phase 3B of a 3-phase 1.3-GHz LTS/HTS NMR magnet

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Title: Modified Phase 3B of a 3-phase 1.3-GHz LTS/HTS NMR magnet Application #: GM114834-11A1 PI: Yukikazu Iwasa, Francis Bitter Magnet Laboratory, Plasma Science and Fusion Center, Massachusetts Institute of Technology, Cambridge MA Date: August 10, 2015 New Abstract Information In the simplest view of NMR, the advantages of higher field are improved sensitivity and resolution. Spectroscopy basically consists of measuring frequencies and amplitudes. Resolution gives frequency information. Sensitivity gives amplitude information. Both sensitivity per unit time in signal averaging experiments and resolution for 3D experiments improve as ω3. Thus, going up in frequency, for example, from 800 MHz to 1.3 GHz, sensitivity and resolution scale up by a factor of 4.3. In solution NMR most protein solution NMR experiments utilize the TROSY effect to optimize the resolution of the experiments. Initially it was predicted that TROSY experiments would be optimal at ~900 MHz. However, more recent experimental data and simulations on several proteins indicate that the resolution is optimized in the range 1200—1400 MHz (vide infra). In magic-angle-spinning (MAS) solid-state NMR, the higher the field the more optimal. Many cutting-edge structural biology questions such as ribosomal protein synthesis, virus entry into cells, ion channels implicated in human diseases, will become accessible to solid-state NMR investigation at higher magnetic fields. This modified Phase 3B program has two specific aims: Aim 1) successful completion of an 800-MHz (18.79 T) HTS insert (H800) comprising 3 nested stacks of DP coils wound with GdBCO tape, that together with a 500-MHz (11.74 T) LTS NMR magnet (L500) available at the FBML, will generate a field of 30.53 T (1.3 GHz 1H frequency); Aim 2) development, continued from Phase 3A, of innovative field-shimming techniques to convert, after completion of this modified Phase 3B program, the 30.53-T L500/H800 magnet to a high-resolution 1.3 GHz NMR magnet (1.3G) capable of producing 1-Hz linewidths. These new field-shimming techniques are essential for NMR magnets that rely on an HTS insert. To achieve Aim 1 in the most efficient, and affordable, manner, we are applying innovative design concepts to build HTS double-pancake (DP) coils: no-insulation winding technique and inside-notch DP coils. The two new shimming techniques, development of which will be continued as Aim 2 in this modified Phase 3B program are persistent-mode HTS shims and “shaking-field” magnet. Upon successful completion of our 1.3G, it will be installed in the MIT-Harvard Center for Magnetic Resonance at the FBML. We believe that our 1.3G will become a vital force in high-field NMR and will serve the entire NMR community in the U.S. for decades to come and have a worldwide impact on medical sciences. Modified Specific Aims The successful completion of an 800-MHz (18.79 T) HTS insert (H800) comprising 3 nested stacks of DP coils wound with GdBCO tape, is one of the Specific Aims of this modified Phase 3B program. The H800 will be combined with a 500-MHz (11.74 T) LTS NMR magnet (L500) presently available at the FBML. In this modified Phase 3B program we will also continue development, initiated in Phase 3A, of new field shimming techniques. After completion of this modified Phase 3B program, we will apply the shimming techniques to the H800, thereby converting the resultant 30.53-T LTS/HTS magnet to a high-resolution 1.3-GHz NMR magnet (1.3G). The key benefits of a 1.3-GHz magnet are higher resolution and sensitivity. This enables the examination of complex molecular systems such as proteins and nucleic acids in a much shorter time, or with smaller quantities of material. This modified Phase 3B program has two specific aims: 1) successful completion of H800, that together with L500 will generate a field of 30.53 T and a 1H frequency of 1.3 GHz; 2) development, continued from Phase 3A, of field-shimming techniques to convert, after completion of this modified Phase 3B program, the 30.53-T L500/H800 magnet to a high-resolution 1.3 GHz NMR magnet (1.3G) capable of producing 1-Hz linewidths. These new field shimming techniques are essential for NMR magnets that rely on HTS tape conductor. As discussed further in 3. Research & Strategy, to achieve Aim 1 in the most efficient, and affordable manner, we are applying innovative design concepts to build HTS DP coils: no-insulation winding technique and inside-notch DP coils. To ensure the highest possible probability to achieve Aim 2 we have initiated in Phase 3A, and to continue in this modified Phase 3B program, development of two innovative field shimming techniques: persistent-mode HTS shims and “shaking-field” magnet. As also discussed in 3. Research & Strategy, an L500/H800 combination is considerably less expensive than a combination of a <4.2-K operated 900-MHz LTS magnet (L900) and a 400- MHz HTS insert (H400)—this will become a reality when the HTS insert becomes standard for a >1-GHz NMR magnet. Moreover, because the footprint of a >1-GHz LTS/HTS magnet is essentially determined by that of the LTS component, space-wise our L500/H800 combination is more efficient, and certainly desirable, than an L900/H400 combination. Modified