Is there a scientific field that focuses exclusively on scientific instrumentation research? I would like to know if there is any scientific field that focuses exclusively on scientific instrumentation research? I know that each field (and sub-field) has its own instrumentation and apparatus, but my question is about the existence of a community that explore the nature and the methodological sides of those instruments.
Yes, there exist such a field, but actually the development of scientific instrumentation is transversal to many fields. Note, however, that one typically specializes in scientific instrumentation of a certain kind. With just one life available, one cannot cover all types of instruments!

One specific field is that of metrology. Metrology is the science of measurement, and many metrologists are involved in the development of measuring systems and methods for accurate measurements. For instance, as my profile says, I'm a metrologist and I work in the field of primary electrical resistance and impedance measurements. I spend most of my time developing devices and measuring systems for that quantity, and for the realization of its unit, the ohm. Metrologists also collaborate with the industry, to improve the development of certain types of instruments. It's not uncommon that measuring systems that were once developed by research laboratories can be now bought as off-the-shelf instruments from various companies. In a few institutions around the world, and especially in Europe, one can find PhD programmes or schools dedicated to metrology.

However, not all scientific instruments are dedicated to accurate measurements, and many instruments are also developed by researchers working in specific disciplines. So, for instance, particle physicists may collaborate with engineers to develop particle and radiation detectors. As I said, the development of scientific instrumentation is really transversal to many fields.

It is common for those who work at the development of instrumentation to have a degree in engineering or physics, but these are not the only possibilities indeed. You definitely need a broad knowledge, though.

You can find papers on instrumentation on certain dedicated journals, but also in journals about specific disciplines. Some dedicated journals are the following (list by no means exhaustive):


Metrologia: This is the main journal dedicated to the world of metrology. You can find papers dedicated to primary measuring systems.
Review of Scientific Instruments: As the title says, this is a journal specifically dedicated to scientific instruments, of all kinds. Quite well known.
Measurement Science and Technology: Another journal dedicated to the world of measuring instruments, with a broader scope with respect to Metrologia.
IEEE Transactions on Instrumentation and Measurement: Journal with a very broad scope, where you can find papers dedicated to instrumentation, sensors, algorithms etc.