What is the need to transform the kinetic energy of a single proton to thermal energy in a large ensemble of particles?
Temperature , a thermodynamic measure, is defined only statistically, not for a single particle. An experiment could be set up but it has no meaning since the momentum of a charged particle can be easily measured by its bending in a magnetic field, which is the way charged particle energies are measured in particle experiments.
A second way is using calorimetry which measures both charged and neutral energies, in calorimeters, with much larger errors. Note "calorimetry". It is the depositing of energy in large number of particles in a medium, calibrated to give the energy of the impinging particle.( I guess one could get a temperature from the energy deposited but that would be putting the cart before the horse).
In any case, if bending a track in a magnetic field needs a simple calculation to get the energy of the proton, getting it from the calorimeter needs a lot more calculations. Everything in particle physics depends on calculations.