  Single particle detection is described in a limited way by simple models of
measurements in quantum field theory. We show that a general approach, using
Kraus operators in spacetime constructed from natural combinations of fields,
leads to an efficient model of a single particle detector. The model is free
from any auxiliary objects as it is defined solely within the existing quantum
field framework. It can be applied to a large family of setups where the time
resolution of the measurement is relevant, such as Bell correlations or
sequential measurement. We also discuss the limitations and working regimes of
the model.
