Testing the HeRL02-RM Helium Reliquefier

While Cryomech has offered a range of Helium Reliquefiers for many years, the HeRL02-RM was the first product on the market to be specifically designed and manufactured to meet the capacity of an NMR magnet and the needs of sensitive NMR spectroscopy.

During development of the HeRL02-RM, the R&D team worked closely with customers to test its performance. The results of those tests provide the vital data proving that it doesn’t interfere with the results of NMR spectroscopy – making it ideally suited for its intended purpose.

In this article, we take a closer look at the testing process and the results achieved.

HeRL02-RM – A Helium Reliquefier for NMR

NMR is the leading technique for determining the structure of organic compounds. NMR spectroscopy relies on superconducting magnets, which require liquid helium for cooling, ensuring the magnets remain at the necessary low temperatures for optimal performance.

Helium Reliquefiers play a vital role in conserving helium. The HeRL02-RM creates a closed-loop, zero-boil-off system. Boiled-off helium is passed through a vapor return line to the Pulse Tube Cryocooler-powered reliquefier, which instantly liquefies the boil-off and returns it to the magnet’s helium bath. This eliminates the need for any more liquid helium orders or transfers.

Designed specifically for helium recovery from a single Nuclear Magnetic Resonance (NMR) instrument, the HeRL02-RM employs unique vibration mitigation techniques, such as a remote motor, to ensure that vibration from the device doesn’t affect any NMR spectra.

The Role of Rigorous Testing

An important part of developing products for specific applications is testing them in real experiments, ensuring that the product caters to the needs of our customers in a reliable way. In the case of the HeRL02-RM, rigorous testing of the vibration mitigation was of key importance.

For the HeRL02-RM to successfully support NMR experiments, we needed to ensure that no vibrations were visible in any potential spectra our customers would be producing. Therefore, the HeRL02-RM has been field-tested by many NMR experts, on multiple units of varying magnet strength.

We partnered with researchers from several universities, such as Western Washington University and The City University of New York, to gather test data before and after installing our reliquefier, to get relevant results from the research community. These tests have proved that introducing the reliquefier has not had any effect on the results – showing that the HeRL02-RM excels at what it was designed for. 

Let’s take a closer look at the results, and the data from the tests.

Western Washington University Test Data

The team at Western Washington University was eager to test out a reliquefier on their own magnet in the anticipation of ordering their own. Once installed on their 500MHz instrument, the usual leak checking was performed, but this time a leak was found.

Thanks to the installation of the NMR reliquefier, they were able to discover that this leak was coming from cracked O-rings within the magnet which they were then able to remedy.

Following the repair, Western Washington produced the data below, further reassuring us that the HeRL02-RM performs exceptionally without negatively affecting NMR performance. As you can see from the charts, the results with the HeRL02-RM are actually slightly better than the control experiment.

Similarly, the data below shows that utilizing the HeRL02-RM resulted in 6-8% better noise sensitivity:

The City University of New York (CUNY) Test Data

The College of Staten Island (The City University of New York) was also gracious enough to test out our NMR reliquefier in their lab. They were interested in acquiring a unit of their own, so this was an opportunity for them to test the HeRL02-RM while also adding to the Bluefors catalog of test data.

Read the full report here or the excerpt of their findings below.

Report on the Effect of Helium Recycling System on protein NMR Spectrum Quality

Purpose

This report aims to assess the impact of a helium recycling system on NMR spectral quality. A series of 2D and 3D experiments were conducted and compared before and after the installation of the helium recycling system.

Summary of Results

During the tests, Research Associate Jianqin Zhuang discovered the following: “We assessed the impact of the helium recycling system on NMR spectral quality by performing 2D 15N HSQC and 3D HNCA, HNCACB experiments using 13C, 15N double-labeled ubiquitin samples. Signal-to-noise ratio (S/N) and line width were evaluated before and after the system’s installation, revealing minimal changes in spectral quality with stable S/N and line width values. Additionally, stability testing with rapid 15N HMQC experiments confirmed that the recycling system maintained spectral integrity.

To summarize, CUNY found that the HeRL02-RM reliquefier preserved NMR spectral data quality without compromising signal fidelity.

Collaborative Product Development

In conclusion, by collaborating with universities and researchers in the field, we have been able to gather valuable test data about the performance of the HeRL02-RM Helium Reliquefier, specifically designed for NMR instruments. Thus far, rigorous testing has played an important role in successfully proving the reliability of the product’s vibration mitigation – a critical feature for sensitive NMR spectroscopy. Over the coming months, we will be testing in a wide range of different magnet brands, fields, and configurations to ensure that our offering can remain truly magnet agnostic.

Our mission is to support researchers and scientists to go further, and that’s why their feedback and expertise are invaluable in refining our products to better serve their needs. By fostering strong relationships with the scientific community, we can develop new products that meet the demanding needs of our customers and enable progress.

Read more about the Cryomech HeRL02-RM Helium Reliquefier, or contact our sales engineers for more information.