A readout circuit coupleable to at least one photodiode of a photomultiplier array, the readout circuit comprising at least one channel circuit said at least one channel circuit is coupleable to the at least one photodiode, the channel circuit comprising: a first resistor (Rd), coupleable at one end to the anode of the at least one photodiode, and an input stage, coupled to the other end of the first resistor, the input stage comprising: a current mirror configuration having at least a first gain path, the first gain path having an input branch with at least one input amplifier and a first output branch with at least one mirror amplifier having its base and emitter connected to the base and emitter of the input amplifier of the input branch; characterized in that it further comprises a high frequency feedback circuit arranged between the base of the input amplifier and the input of the current mirror configuration, the high frequency feedback circuit comprises at least a first amplifier (Qf) and a second amplifier (Mf), the first amplifier (Qf) having a collector coupled to a power supply voltage (Vdd), a base coupled to a collector of the second amplifier (Mf) and an emitter coupled to the base of the input amplifier and to earth via a current source, the second amplifier (Mf) having a base coupled to earth via a first capacitor and an emitter coupled to the input of the current mirror configuration; and wherein a low frequency feedback circuit is coupled between the base of the second amplifier (Mf) and the input of the input branch. said at least one channel circuit is coupleable to the at least one photodiode, the channel circuit comprising: a first resistor (Rd), coupleable at one end to the anode of the at least one photodiode, and an input stage, coupled to the other end of the first resistor, the input stage comprising: a current mirror configuration having at least a first gain path, the first gain path having an input branch with at least one input amplifier and a first output branch with at least one mirror amplifier having its base and emitter connected to the base and emitter of the input amplifier of the input branch; characterized in that it further comprises a high frequency feedback circuit arranged between the base of the input amplifier and the input of the current mirror configuration, the high frequency feedback circuit comprises at least a first amplifier (Qf) and a second amplifier (Mf), the first amplifier (Qf) having a collector coupled to a power supply voltage (Vdd), a base coupled to a collector of the second amplifier (Mf) and an emitter coupled to the base of the input amplifier and to earth via a current source, the second amplifier (Mf) having a base coupled to earth via a first capacitor and an emitter coupled to the input of the current mirror configuration; and wherein a low frequency feedback circuit is coupled between the base of the second amplifier (Mf) and the input of the input branch. a first resistor (Rd), coupleable at one end to the anode of the at least one photodiode, and an input stage, coupled to the other end of the first resistor, the input stage comprising: a current mirror configuration having at least a first gain path, the first gain path having an input branch with at least one input amplifier and a first output branch with at least one mirror amplifier having its base and emitter connected to the base and emitter of the input amplifier of the input branch; characterized in that it further comprises a high frequency feedback circuit arranged between the base of the input amplifier and the input of the current mirror configuration, the high frequency feedback circuit comprises at least a first amplifier (Qf) and a second amplifier (Mf), the first amplifier (Qf) having a collector coupled to a power supply voltage (Vdd), a base coupled to a collector of the second amplifier (Mf) and an emitter coupled to the base of the input amplifier and to earth via a current source, the second amplifier (Mf) having a base coupled to earth via a first capacitor and an emitter coupled to the input of the current mirror configuration; and wherein a low frequency feedback circuit is coupled between the base of the second amplifier (Mf) and the input of the input branch. a current mirror configuration having at least a first gain path, the first gain path having an input branch with at least one input amplifier and a first output branch with at least one mirror amplifier having its base and emitter connected to the base and emitter of the input amplifier of the input branch; characterized in that it further comprises a high frequency feedback circuit arranged between the base of the input amplifier and the input of the current mirror configuration, the high frequency feedback circuit comprises at least a first amplifier (Qf) and a second amplifier (Mf), the first amplifier (Qf) having a collector coupled to a power supply voltage (Vdd), a base coupled to a collector of the second amplifier (Mf) and an emitter coupled to the base of the input amplifier and to earth via a current source, the second amplifier (Mf) having a base coupled to earth via a first capacitor and an emitter coupled to the input of the current mirror configuration; and wherein a low frequency feedback circuit is coupled between the base of the second amplifier (Mf) and the input of the input branch.