Triple point immersion cell article

1. A triple point immersion cell article for determining a triple point of a non-metallic analyte, the triple point immersion cell article comprising:

a first cryochamber comprising a first cryo-zone;

a second cryochamber comprising a second cryo-zone, the second cryochamber being:

nested and disposed in the first cryochamber; and

thermally isolated from an exterior environment of the triple point immersion cell article by the first cryochamber;

a third cryochamber comprising a third cryo-zone, the third cryochamber being:

nested and disposed in the second cryochamber;

thermally isolated from the exterior environment by the first cryochamber and the second cryochamber; and

thermally isolated from the first cryochamber by the second cryochamber; and

a fourth cryochamber comprising a fourth cryo-zone, the fourth cryochamber being:

nested and disposed in the third cryochamber;

thermally isolated from the exterior environment by the first cryochamber, the second cryochamber, and the third cryochamber; and

thermally isolated from the second cryochamber by the third cryochamber; and

a triple-point pressure vessel comprising a fifth cryo-zone, the triple-point pressure vessel being:

nested and disposed in the fourth cryochamber;

thermally isolated from the exterior environment by the first cryochamber, the second cryochamber, the third cryochamber, and the fourth cryochamber; and

thermally isolated from the third cryochamber by the fourth cryochamber; and

a thermowell disposed in the triple-point pressure vessel, the triple-point pressure vessel being directly accessible from the exterior environment via thermowell.

2. The triple point immersion cell article of claim 1 , further comprising a first cryocooler in thermal communication with the first cryochamber.

3. The triple point immersion cell article of claim 2 , wherein the first cryocooler actively cools the first cryochamber to produce the first cryo-zone.

4. The triple point immersion cell article of claim 2 , wherein the first cryocooler comprises a Stirling cycle cryocooler.

5. The triple point immersion cell article of claim 1 , further comprising a second cryocooler in thermal communication with the second cryochamber.

6. The triple point immersion cell article of claim 5 , wherein the second cryocooler actively cools the second cryochamber to produce the second cryo-zone.

7. The triple point immersion cell article of claim 5 , wherein the second cryocooler comprises a Stirling cycle cryocooler.

8. The triple point immersion cell article of claim 1 , wherein the first cryo-zone and the second cryo-zone are subjected to closed-cycle refrigeration in an absence of a liquid cryogen.

9. The triple point immersion cell article of claim 1 , wherein the fourth cryo-zone is an adiabatic zone with respect to a triple point transition temperature of non-metallic analyte.

10. The triple point immersion cell article of claim 1 , wherein the first cryochamber, the second cryochamber, the third cryochamber, and the fourth cryochamber are reversibly demountable and re-mountable from one another.

11. The triple point immersion cell article of claim 1 , wherein the triple-point pressure vessel accommodates a fixed point of the non-metallic analyte from 75 K to 175 K.

12. The triple point immersion cell article of claim 1 , wherein the fourth cryo-zone provides a stable and reproducible melt plateau for the non-metallic analyte.

13. The triple point immersion cell article of claim 1 , wherein the non-metallic analyte comprises a rare gas condensate.

14. The triple point immersion cell article of claim 1 , wherein the triple-point pressure vessel and triple-point cell interior volume receive a long-stem thermometer or capsule-type thermometer for calibration at the triple point of the non-metallic analyte.

15. The triple point immersion cell article of claim 1 , wherein a pressure of the first cryochamber, the second cryochamber, the third cryochamber, and the fourth cryochamber is high-vacuum.

16. The triple point immersion cell article of claim 1 , wherein the first cryo-zone, the second cryo-zone, the third cryo-zone, and the fourth cryo-zone are subjected to active control.

17. The triple point immersion cell article of claim 1 , further comprising a thermowell with a length that is from 10 cm to 100 cm to receive a long-stem thermometer,

wherein the thermowell is in thermal communication with the first cryo-zone, the second cryo-zone, the third cryo-zone, and the fourth cryo-zone and in mechanical communication with the first cryochamber, the second cryochamber, the third cryochamber, the fourth cryochamber, the triple-point pressure vessel, the triple-point cell interior volume, and the thermowell receiving helium as a heat exchange gas at a pressure from 1 millibar (mbar) to 1.3 bar.

18. The triple point immersion cell article of claim 1 , further comprising a vacuum chamber housing disposed around the first cryochamber.

19. A process for determining a triple point of a non-metallic analyte with the triple point immersion cell article of claim 1 , the process comprising:

evacuating a vacuum chamber in which the first cryochamber is disposed;

cooling the first cryo-zone, the second cryo-zone, the third cryo-zone, and the fourth cryo-zone with a cryocooler;

flowing the non-metallic analyte into the triple point cell interior volume to partially condense the non-metallic analyte;

inserting an immersion cooler in the thermowell to complete condensation of the non-metallic analyte;

initiating freezing of the non-metallic analyte;

removing the immersion cooler;

introducing a calibrated standard platinum resistance thermometer into the thermowell;

flowing helium heat-exchange gas in the thermowell;

adjusting a set point temperature of each of the first cryochamber, the second cryochamber, the third cryochamber, and the fourth cryochamber to a selected value for the non-metallic analyte;

pulse heating of the triple point cell pressure vessel in energy increments;

adjusting a set point of the fourth cryo-zone to an adiabatic condition;

suspending pulse heating;

removing the calibrated standard platinum resistance thermometer;

disposing a test standard platinum resistance thermometer into thermowell;

removing the test standard platinum resistance thermometer from the thermowell;

re-disposing the calibrated standard platinum resistance thermometer in the thermowell;

resuming pulse melting;

completely melting the non-metallic analyte;

reinserting the immersion cooler into the thermowell; and

refreezing the non-metallic analyte to determine the triple point of the non-metallic analyte.