Advanced instrumentation for DNP-enhanced MAS NMR for higher magnetic fields and lower temperatures
| Autor: | Jun Fukazawa, Yoh Matsuki, Toshitaka Idehara, Toshimichi Fujiwara |
|---|---|
| Rok vydání: | 2015 |
| Předmět: |
Nuclear and High Energy Physics
Biophysics Analytical chemistry 02 engineering and technology 010402 general chemistry 01 natural sciences Biochemistry High-field DNP Magic angle spinning Spectral resolution Instrumentation Spectrometer Chemistry business.industry Cryogenic temperatures 021001 nanoscience & nanotechnology Condensed Matter Physics Polarization (waves) 0104 chemical sciences Magnetic field Optoelectronics 0210 nano-technology business Frequency modulation Field conditions Magic-angle spinning |
| Zdroj: | Journal of magnetic resonance (San Diego, Calif. : 1997). 264 |
| ISSN: | 1096-0856 |
| Popis: | Sensitivity enhancement of MAS NMR using dynamic nuclear polarization (DNP) is gaining importance at moderate fields (B090K) with potential applications in chemistry and material sciences. However, considering the ever-increasing size and complexity of the systems to be studied, it is crucial to establish DNP under higher field conditions, where the spectral resolution and the basic NMR sensitivity tend to improve. In this perspective, we overview our recent efforts on hardware developments, specifically targeted on improving DNP MAS NMR at high fields. It includes the development of gyrotrons that enable continuous frequency tuning and rapid frequency modulation for our 395GHz–600MHz and 460GHz–700MHz DNP NMR spectrometers. The latter 700MHz system involves two gyrotrons and a quasi-optical transmission system that combines two independent sub-millimeter waves into a single dichromic wave. We also describe two cryogenic MAS NMR probe systems operating, respectively, at T ∼100K and ∼30K. The latter system utilizes a novel closed-loop helium recirculation mechanism, achieving cryogenic MAS without consuming any cryogen. These instruments altogether should promote high-field DNP toward more efficient, reliable and affordable technology. Some experimental DNP results obtained with these instruments are presented. |
| Databáze: | OpenAIRE |
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