N-HeliX

Helium or nitrogen gas is cooled in heat exchangers mounted on a two stage, closed cycle cooler. The cold gas then passes into a unique gas delivery system patented by Oxford Cryosystems. This means that N-HeliX can deliver helium down to a base temperature of 28K with a stability of 0.3K whilst keeping helium gas consumption to a minimum.

A typical gas cylinder will last approximately 16 hours, but, as with the Cryostream, the sample temperature is not affected by changing the supply of helium or nitrogen gas, thus enabling long term experiments to be performed. A second gas stream at room temperature provides extra shielding for the cold stream in order to improve the resistance to icing.

A 10mm diameter x-ray transparent shield tube extends around and beyond the crystal to protect the cold stream from atmospheric contamination.

Although it is possible to use the N-HeliX with bottled nitrogen gas, we recommend that the most cost-effective way to run the HeliX is with an in-house piped nitrogen gas supply or a nitrogen gas generator, similar to that used with the Cobra. The nitrogen gas generator can be purchased from Oxford Cryosystems with the N-HeliX if required.