Main Question or Discussion Point
I thought the method was still used in particle detectors (like CMS) to identify particles.That is the historical approach, as the experiments can be done with basic equipment (and as experiment for students). Today, there are more options to measure masses. Some examples:
This was a very fun lab to do indeed.One standard way of measuring the electron mass, once the charge is known, is to use the e/m method of measuring the radius of curvature of a known energy electron in a known magnetic field, as mentioned above.
This can be done in an undergraduate physics lab using a Helmholz coil and the special vacuum tube, as described in http://www.clemson.edu/ces/phoenix/labs/cupol/eoverm/index.html
Be sure to click on Fig. 1 to enlarge it (beautiful photograph). It is very obvious during the experiment that the force on the electron is orthogonal to both the electron velocity and the magnetic field.
~100MHz for protons in a field of 1 Tesla (quite strong) and less for smaller fields. This corresponds to radio frequencies, which can be observed easily.woah seems like a lot of prerequisites are required. How do you measure such a high frequency for instance?
Curvature in magnetic fields? This just gives a momentum measurement. To measure the mass, you need an additional velocity measurement (energy would work in theory, but gives large uncertainties). This can be done, and LHCb and ALICE have several methods to measure the velocity of particles.I thought the method was still used in particle detectors (like CMS) to identify particles.