Relative representation of scientists and engineers on major experiments (especially particle physics)

Question

I am interested in other academics' experiences with large experiments (especially something like the LHC). To what extent do the "engineers" who design and build the machine (solder electronics, assemble quadrupole magnets, etc) interact with "scientists" who determine the program (who might want to test their 11-dimensional model etc)? Do the two sides take an active interest in each other's work and give constructive suggestions to one another? Are the technicians all hired locally? How many in the "engineering" camp have PhDs?

(It's also possible to label the two groups "experimentalists" vs "theorists", though for the former I really mean people involved in the construction and day-to-day operations - I'm not interested in semantics here)

While the Higgs was at a sigma of ~4, I heard that postdocs and PhD students at CERN could volunteer for maintenance and similar tasks, and that those who did would have their names on the "Higgs paper" (hence the notoriously large author lists). Was this true and is it still the case?

Answer 1

I heard that postdocs and PhD students at CERN could volunteer for maintenance and similar tasks, and that those who did would have their names on the "Higgs paper" (hence the notoriously large author lists). Was this true and is it still the case?

There are a lot of maintenance and monitoring work performed by Ph.D candidates and postdocs at CERN and they may be entitled to have their names in a paper if they comply with the minimum requirements.

There are a minimum of night shifts and work hours in one of the experiments to be completed in order to participate as co-author in the papers produced due to work performed during the internship. If I am not in mistake, you need at least 6 months working in one of the experiments to comply with the minimum work hours demanded for co-authoring.

Usually the ones attending internships at CERN are from experimental particles groups with collaboration to one of the experiments (CMS, ATLAS,etc). They are not purely experimentalists, but I am sure that they can not be purely theorists.