Nottingham DNP MAS NMR Facility
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DNP System

Spectrometer

High performance digital AVANCE III 600 MHz (1H Larmor frequency) three-channel NMR spectrometer having the following specifications:

  • Ascend™ wide-bore (89 mm) 14.09 Tesla cryo-magnet, with sweep-coil and autonomous helium recycling system (Ascend Aeon design). The presence of the sweep-coil will aid in testing the efficiency of the radicals and check their field profile for maximal efficiency of DNP. It will also help in designing experiments involving metal ions like Gd for DNP.
  • Double bay 3-channel spectrometer console with 1 kW 1H amplifier, 1 kW X-amplifier, and 500 W X-amplifier. It will be very much suitable for the users to carry out triple channel experiments, as well as experiments involving low amplitude selective pulses. It will also have high power preamplifiers suitable for solid state NMR.
  • BSVT variable temperature unit will be available for those who want to carry out experiments at different temperatures.

MAS pneumatic unit

One of the most important prerequisite for designing an experiment in ssNMR is stable sample spinning and control of the sample spinning. So it is essential here to give a brief description of our pneumatic unit.

  • The unit will be capable of automated spinning of the sample with respect to increasing and decreasing spinning frequencies. This will be beneficial to the researchers designing experiments as a function of spinning frequencies.
  • It will have precise spinning frequency control, and will be highly conducive for experiments which require accurate spinning frequencies, like recoupling in ssNMR.
  • Trigger output for synchronization with rotor, which will be essential for controlling the RF sequences. The trigger output can be encoded in the pulse programme, which will tell the transmitters to start pulsing at a particular time point in the rotational period (generally the beginning).
  • The unit will have automated eject and manual keyboard control.

Gyrotron

The details of our gyrotron system in which a researcher might be interested in are following:

  • Microwave source type: Gyrotron
  • Mode of operation: continuous operation for 10 days or longer
  • Operation frequency: 395 GHz
  • Frequency stability: ± 10 ppm over 12 hrs
  • Output power: 1 – 50 W
  • Output power stability: ± 1% over 12 hrs, achieved with feedback loop
  • Supply voltage: 230V 3-phase
  • Output microwave beam: Gaussian

Probe specification

1. Triple resonance low temperature MAS (Magic Angle Spinning) probe for solid state DNP-NMR configured for biological applications. Equipped with the following features:

  • 3.2 mm MAS system
  • Optimised for 13C and/or 15N observation with 1H high-power decoupling
  • Waveguide, optimized for 395 GHz
  • Sample volume ~ 30 μl
  • Maximum rotation frequency is 24 kHz at room temperature and approximately 14 kHz at 100K
  • Further inserts and high-power filters to cover X/Y nuclei combinations:
Possible X/Y nuclei combinations
 X Y
31P 13C, 29Si, 6Li
7Li 17O
11B 13C, 29Si, 17O
27Al 29Si
13C 2H, 17O, 29Si, 14N, 15
29Si 15N
71Ga 17O

2. Double resonance (HX) MAS (Magic Angle Spinning) probe for solid-state DNP-NMR measurements. Equipped with the following features:

  • 3.2 mm MAS system
  • Optimised for observation in the range 13C to 109Ag with 1H highpower decoupling
  • Sample volume ~ 30 μl
  • Maximum rotation frequency is 24 kHz at room temperature and approximately 14 kHz at 100K

 

Available Radicals

 

The following radicals are available:

  • AMUPol: Sauvée, C. et al. Highly efficient, water-soluble polarizing agents for dynamic nuclear polarization at high frequency. Angew. Chemie - Int. Ed. 52, 10858–10861 (2013).
  • TEKPol: Zagdoun, A. et al. Large molecular weight nitroxide biradicals providing efficient dynamic nuclear polarization at temperatures up to 200 K. J. Am. Chem. Soc. 135, 12790–12797 (2013).
  • TOTAPOL: Song, C et al. TOTAPOL: a biradical polarizing agent for dynamic nuclear polarization experiments in aqueous media. J. Am. Chem. Soc. 128, 11385–90 (2006).

Nottingham DNP MAS NMR Facility

Sir Peter Mansfield Magnetic Resonance Centre
University Park
Nottingham, NG7 2RD

telephone: +44 (0) 115 9514747
fax: +44 (0) 115 9515166
email: spmmrc@nottingham.ac.uk