The present invention relates to a detection device (6) for detecting photons emitted by a
radiation source (2) and capable of adjusting ballistic deficit. The detection device (6) comprises a pre-amplifying unit (11) (such as, e.g., a charge-sensitive
amplifier), a shaping unit (60) comprising a feedback
discharge unit (13, I) (such as, e.g., a feedback
resistor or a feedback
current source), and a feedback
discharge control unit (50) coupled to the feedback
discharge unit (13, I). The feedback discharge
control unit (50) is adapted to, e.g., adjust a resistance of a feedback
resistor (and / or to adjust the current value of the feedback
current source) if an electrical pulse generated by the shaping unit (60) does not exceed at least one energy comparison value (X1, X2, . . . , XN). The feedback discharge
control unit (50) is adapted to not adjust the parameter of the feedback discharge unit (13, I) if the electrical pulse exceeds the at least one energy comparison value (X1, X2, . . . , XN). By tuning the feedback
resistor operating point (or the feedback
current source operating point), the ballistic deficit can be adjusted to a predefined expected value.