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Microwave Source for ODNP-Enhanced NMR Spectroscopy

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Related Product: X-Band ODNP Probe

Overhauser DNP Spectroscopy


Overhauser Dynamic Nuclear Polarization (ODNP) enhanced NMR spectroscopy at 9 GHz (0.35 T, 15 MHz 1H NMR frequency) is a powerful method for site-specific studies of the accessibility and translational dynamics of water molecules at or near bio-macromolecules, membrane proteins, or polymer/solvent interfaces [1,2]. Although the method has been in practice since the 1960s, it has just recently been successfully applied in structural biology and material science. The unique instrumentation requirements previously limited the application of ODNP-enhanced NMR spectroscopy, specifically the lack of commercially available microwave sources and DNP probes that are compatible with existing EPR instrumentation.

Upgrade any existing EPR Spectrometer

Unlike high-field DNP-enhanced solid-state NMR experiments, ODNP -enhanced NMR spectroscopy at 9 GHz does not require a large superconducting NMR magnet or a gyrotron as the microwave source. In fact, any commercially availabe or home-built X-band EPR spectrometer, often found in academic spectroscopy facilities, can be easily upgraded with ODNP capabilities.

A turn-key microwave source for you to focus on your research

The Bridge12 MPS 9 GHz is an easy-to-use X-band microwave source for ODNP spectroscopy. The maximum output power of commercially available, state-of-the-art EPR spectrometer is typically limited to < 300 mW, which is insufficient to drive the ODNP effect into saturation.

The Bridge12 MPS is a simple add-on for existing EPR spectrometers and can deliver up to 10 W of microwave power to the sample. The system features easy-to-use front panel operation, a concise design, and several failsafe features to protect your sample and your EPR instrumentation. You don’t have to be an expert in microwave technology to operate this system. Instead of troubleshooting home-built instrumentation, keep the focus on your research. Simply set the correct microwave frequency and output power, enable the microwave output, and start recording ODNP-enhanced NMR spectra. For more advanced users, the system features an optional external trigger to modulate the microwave power directly from the NMR console, and a USB interface for deeper integration of the source into the target application.

Easy to operate user interface

The Bridge12 MPS features a simple and concise user interface. A large, five inch front panel display is designed to show only the important values in an easy-to-read font size, even from a distance. Users can switch between the default screen and an advanced screen for more operation parameters.

A modular platform with many additional options

The Bridge12 MPS has a modular design, which can be upgraded with various features. The unit has a front panel SMA breakout for users who would like to add external components such as fast microwave switches, or mixers for pulse shaping (e.g. AWG).

The system has an integrated power detector to constantly monitor the forward and reflected microwave power and also disables the microwave power once the reflected power exceeds a certain level. Additional tuning/matching features can be added to display the cavity tuning in real time.

Five additional digital input/output lines can be individually programmed for user-specific functions. For example, the instrument can be configured to run through a predefined power schedule, to fully automate ODNP experiments.

ODNP connection kit

Bridge12 offers a connection kit for seamlessly integrating the ODNP microwave source and probe into existing EPR instrumentation. This allows a user to simply switch back and forth between EPR and DNP operation. The kit includes a waveguide switch that can be operated manually or automatically to ensure the safety of your EPR equipment.

Integrated NMR spectrometer

The system can be equipped with a single-channel, compact NMR spectrometer. The system is entirely controlled using OpenVnmrJ. For more information take a look here.

The Bridge12 MPS for ODNP-enhanced NMR spectroscopy is also available for experiments at K (24 GHz) and Q (35 GHz) band.

[1] Franck, J.M., et al., Quantitative cw Overhauser effect dynamic nuclear polarization for the analysis of local water dynamics. Prog. Nucl. Magn. Reson. Spectrosc., 2013. 74(0): p. 33-56.

[2] Franck, J. M., and Songi Han. “Overhauser Dynamic Nuclear Polarization for the Study of Hydration Dynamics, Explained.” In Methods in Enzymology, 615:131–75.

Technical Specifications

  • Frequency Range: 8.5 – 11.5 GHz (also available for Q and K-band spectrometers)
  • Maximum Output power: 5 or 10 W (cw). Continuous attenuation in steps of 0.01 dB
  • Operation: Front Panel operation. Digital interface (USB) for remote operation (optional)
  • TTL pulse modulation (optional): 100 ns minimum pulse length, 50 % minimum duty cycle (shorter pulses available).
  • Temperature monitor and safety switch to prevent overheating of the amplifier.
  • System size (W x H x D): 12 x 7 x 14 (inch), 30.5 x 17.8 x 35.6 (cm)
  • System weight: 3.3 lbs (1.5 kg)
  • Input power: 110 – 220 V (50/60 Hz)

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