
Building a towering millikelvin thermometer - elorant
http://news.fnal.gov/2018/11/how-to-build-a-towering-millikelvin-thermometer/
======
John_KZ
In my opinion, the majority of useful work done by CERN is not in the domain
of theoretical physics, but in that of engineering. A lot of really bizarre
configurations are build (with respect to day-to-day engineering challenges),
with extreme requirements that push materials and other forms of engineering
forward. Personally I have discovered papers by CERN where they test things
that are very useful to me, but if it wasn't for their massive budget,
available tools and personnel, nobody else would be be able to, or bother
testing and publishing.

~~~
scottlocklin
Agree; and the engineering stuff that comes out of CERN is more important than
the experimental physics as well.

Same was true of NASA back in the day; it was amazing how much practical
knowledge on vacuum chambers _alone_ was generated in the late 50s early 60s.

------
benj111
So could the op or someone else comment on why the temperature profiler is so
long/tall.

Am I understanding correctly that there is supposed to be a temperature
differential along its length to measure? Why would you want to do that, would
mixing the argon introduce too much energy?

~~~
wnkrshm
There is a better article on the subject here [0] - it's indeed a long tube
with lots of temperature sensors (48) to measure temperatures at different
depths in the liquid argon volume.

The data can be used to check whether the cooling and filtration system is
working correctly and correlate that with contamination of the liquid argon by
other material (e.g. outgassing from building material).

These detectors aren't described (but mentioned) in the original DUNE design
report [1], but it's an extremely interesting 'read' if you want to get a feel
for which parts work together in the detectors.

[0] [https://phys.org/news/2018-08-temperature-
protodune.html](https://phys.org/news/2018-08-temperature-protodune.html) [1]
[https://arxiv.org/abs/1601.02984](https://arxiv.org/abs/1601.02984)

