Thanks for question. The sample was cooled exactly in this way, using LN2, but in slighlty different configuration. Liquid nitrogen was flowing only through motorized manipulator. Sample holder and sample were not in direct contact with LN2.

The sample was mounted on the sample holder, which in turn was placed on the manipulator, and all this stuff was cooled to temperature slightly below desired Temp, and then the sample was heating up to desired Temp (in all cases below 0C). Temperature was measured by thermocouple mounted in the sample holder, and what is more, temperature was stabilized of approx. 30 min before bombarding with accuracy of 0.2C, also during bombardment (as I remember).

With best regards too!

Dear Salah,

I would expect the temperature 77K = -196C.

With Regard

R. Mitdank