How to make a "super-cooled" vacuum?

Factual Questions
1

I’m always reading about this new particle or process designed with the aid of, or only existing, in some vacuum “1 bazillionth above absolute zero.”

How do they make such devices?
How do they even measure such temperatures?

2

Vacuum has no temperature. Temperature is a measure of energy content of a substance. No substance, no temperature.
As for how you achieve really low temperatures, that’s a fascinating topic on its own. There are many stratagems and dodges, depending on what your temperature already is. The lower you go, the harder it becomes and thecleverer you have to be.
here’s a start:

3
4

Thank you. The measurement link was more my speed…But I’m interested enough to kind of slog though, with minimum understanding–Welcome to my World–the other stuff.
Leo

5

A bit thin on details, but a good story.

6

Thank you very much.

7

Sorry, this is incorrect.

It’s a fascinating story.