Cryoprobe

From NMR Wiki

Cryoprobe or Cold probe is a technology where probe coil and/or built-in signal preamplifier are cooled with a stream of He gas at ~10-25K (?) This reduces the level of thermal noise generated by electronic circuits and components of the signal receiver itself and allows detect weaker signals.

The result is that signal to noise ratio can increase several times, e.g. ~3.5x, vs. a room temperature probe.

Typical parts included into the cryo-probe system

• Helium compressor (expected lifetime 3-5 years of continuous operation, cost ~$20,000)

Maintenance

Cryoprobes require periodic maintenance and careful operation.

For example, care must be taken so that water, cooling the He compressor is at suggested temperature (or even slightly cooler). Even if water temperature is only slightly above nominal, the compressor oil may overheat and start breaking down, and generating gases that will condense at cryogenic temperatures inside the system. This may lead to breakage of mechanical parts.

Gas filters (removing contaminants from He) need periodic replacement.

Expenses

• ~12,000 or more