A device for processing a signal (i) derived from a particular detector, the device including an integrator for measuring the total charge transported by an input signal (i2) feeding the integrator for a predetermined time interval. The device further includes a plurality of units for receiving detector signal (i) derived from the particle detector, reducing the background noise present in the detector signal (i), and producing the input signal (i2). The invention is applicable to various devices and appliances for measuring flow of particles such as photons.