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.
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?
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.
