The NMR facility has three high-field FT-NMR instruments: a Bruker Avance Neo 500 MHz with a Prodigy Cryoprobe and a 24-position SampleCase sample changer; a Varian NMR-System 500 MHz with a OneNMR probe and 7510-AS 12 position sample changer; and a Varian INOVA 300 MHz with a quad-nucleus probe. All three instruments have pulsed-field gradients and variable-temperature accessories. The two 500 MHz instruments having auto-tuning probes with a broad range of accessible nuclei.
The Bruker Avance Neo 500 MHz instrument was installed in 2019. The default probe installed in this magnet is a Prodigy cryoprobe which has twice the sensitivity on the 1H channel and three times the sensitivity on the X channel compared to the OneNMR probe on our Varian 500 MHz instrument. We also have an iProbe with similar sensitivity to the OneNMR probe on our Varian 500 MHz instrument. Both of these probes are auto-tuning, providing access to a broad range of nuclei, and have pulsed-field gradients, for automated shimming and modern gradient-filtered techniques. The magnet is also equipped with a 24-position SampleCase sample changer to improve the throughput and reduce wasted time.
The Varian NMR-System 500 MHz instrument was installed in 2007. The default probe installed in this magnet is a Varian OneNMR probe. This probe has enhanced 1H RF homogeneity so that the sensitivity of the 1H channel is similar to that of an indirect probe, while maintaining the high X channel sensitivity of a direct probe. This probe is auto-tuning, providing access to a broad range of nuclei, and has pulsed-field gradients, for automated shimming and modern gradient-filtered techniques. A 12 position 7510-AS sample changer is available. Traditional direct and indirect probes with pulse-field gradients are available, but they require manual tuning.
The Varian Inova 300 MHz instrument was installed in 1996. This default probe installed in this magnet is a Varian quad-nucleus probe which allows acquisition of 1H, 13C, 31P and 19F spectra without manual tuning. This probe has pulsed-field gradients, for automated shimming and modern gradient-filtered techniques. A broadband probe is available, allowing detection of broad range of NMR active nuclei. However, these low-frequency nuclei benefit from higher field instruments, so the 500 MHz instruments are recommended for these applications.
Due to ongoing shortages and rising helium prices, we purchased and began renovations for a helium recovery system in late 2019. The system arrived in 2020 and we began operation in early 2021. The recovery system is currently recycling the helium boil-off from six superconducting magnets in the department. The current setup produces roughly 5100 L of liquid He per year and delivers about 2800 L of liquid He to the six magnets with a recovery rate of 95%.
Our helium recovery system uses a CryoMech liquid helium plant. This includes
- an atmospheric pressure recovery bag,
- a recovery compressor,
- medium pressure storage tanks,
- an automatic helium purifier,
- a LHeP22 helium liquefaction plant with a 150 L collection dewar.
The manifolds that connect the magnets to the He collection circuit are based on the setup at Yale’s NMR facility.
More details are found here.