  This is the second paper on a new formalism for relativistic quantum
measurements. Here, we construct a fully relativistic model for detectors that
takes into account the detector's state of motion, intrinsics dynamics, initial
states and couplings to the measured field. The dual classical/quantum
description of the detector is implemented by using a master-equation type of
approximation for the coarse-grained pointer variables. Then we identify the
probabilities that correspond to ideal measurements, i.e., measurements that
are largely insensitive to modeling details of the apparatus. The Unruh-Dewitt
and Glauber detectors are recovered at the appropriate limits. We employ our
results to models of particle detection, photodetection and relativistic spin
measurements, and we derive an ideal distribution for relativistic
time-of-arrival probabilities.
