A Super-Wide Bore DNP System for Multiple Sample Polarization: Cryogenic Performance and Polarization at Low Temperature

• Published in: Applied magnetic resonance Vol. 43; no. 1-2; pp. 167 - 180
• Main Authors: Crémillieux, Yannick, Goutailler, Florent, Montcel, Bruno, Grand, Dominique, Vermeulen, Gérard, Wolf, Pierre-Etienne
• Format: Journal Article
• Language: English
• Published: Vienna Springer Vienna 01.07.2012; Springer Nature B.V; Springer Verlag
• Subjects: Atoms and Molecules in Strong Fields; Cooling; Copper; Design; Diameters; Engineering Sciences; Glycine; Helium; Laser Matter Interaction; Liquid helium; Low temperature; Magnetic fields; Organic Chemistry; Physical Chemistry; Physics; Physics and Astronomy; Polarization; Radiation; Signal and Image processing; Solid State Physics; Spectroscopy/Spectrometry; Stainless steel; Temperature; United States > US; Microwave Cavity; Solenoid Coil; Dynamic Nuclear Polarization; Nuclear Magnetic Resonance Signal; Liquid Helium
• ISSN: 0937-9347; 1613-7507
• DOI: 10.1007/s00723-012-0354-5

The volume of polarized sample and the delay required between successive polarizations of samples represent serious constraints for dynamic nuclear polarization (DNP) applications. With these limitations in mind, a DNP polarizer, based on a super-wide bore (150-mm diameter) vertical magnet operating at 3.35 T, was designed. The working diameter for loading/unloading samples is equal to 46 mm and the microwave cavity can accommodate up to three samples. The cryostat can be cooled to 4.2 K in typically 2 h and filled with liquid helium in 1 h. Once filled with liquid helium, the cryostat hold time is on the order of 4 h and a minimum temperature of 1.19 K can be reached. In situ polarization levels at low temperature were measured between 5 and 10 % in single and multiple samples of 13 C-labeled urea and glycine.