A spectrometer designed for 6.7 and 14.1T DNP-enhanced solid-state MAS NMR using quasi-optical microwave transmission

A quasi-optical and corrugated waveguide microwave transmission system for simultaneous dynamic nuclear polarization NMR on two separate 14.1 T spectrometers

“…We designed the microwave propagation system following some of the concepts proposed by Lesurf [26,27] to control the beam (power and polarization), continuously monitor its power, and transmit the microwaves in a nearly loss-free manner. This section describes the design of the microwave handling system, comprised of quasi-optical tables and corrugated waveguides, as well as the characterization of its performance.…”

“…At the exit of the gyrotron’s waveguide, the microwave beam is transmitted in free space and manipulated via a combination of plane and concave ellipsoidal mirrors [26,27,30], using a breadboard table that allows precise positioning and alignment of all optical elements (see Figs. 1 and 3 for further details).…”

Theoretical aspects of Magic Angle Spinning - Dynamic Nuclear Polarization

“…(c) Corresponds to a nuclear relaxation time of T1;n ¼ 0:05 s and (d) to T1;n ¼ 4 s. The insert in figure (b and d) represents the distribution of ðPaðtÞ À P b ðtÞÞ max for the positive DNP spectrum part, respectively at B0 ¼ 9:934 T and 18.788 T. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article. )spectrometers operating at fields corresponding to 600 and 800 MHz proton Larmor frequency were constructed in different laboratories and commercialized[57][58][59][60]. Increasing the external magnetic field broadens the inhomogeneous EPR linewidths of the radicals and therefore increases all the ''velocity'' LZ coefficient n M t , and in particular influences the SE and CE LZ ratios that are proportional to ðA AE…”

Development of a Compact sub-THz Gyrotron FU CW CI for Application to High Power THz Technologies

“…On the basis of the importance of CW operation, we have begun to develop Gyrotron FU CW series in 2003 [13,14]. We have already developed more than ten CW gyrotrons and applied them to DNP-NMR spectroscopy, [15][16][17][18][19][20] X-ray detected magnetic resonance (XDMR) measurement [21], preliminary experiments on hyperfine structure of positronium [22,23], preliminary experiment on Bloch oscillator, [24] high frequency ESR spectroscopy [11]. and development of new medical technology [25][26][27][28].…”

“…Those are Gyrotrons FU CW II [29,32] and FU CW VI [15] , for 600 MHz DNP-NMR experiment [17,31] in Osaka University, Institute of Protein Research, Japan, Gyrotron FU VII [16] , for 300 MHz and 600 MHz DNP-NMR experiment [19] in Warwick University, UK and Gyrotron FU CW IV [30] for 200 MHz DNP-NMR experiment [18] in FIR FU. Similar pioneering developmental works were carried out in MIT [33][34][35] for 400 MHz and 700 MHz DNP-NMR spectroscopy [34,36,37].…”