Electron multiplier based detector

The invention relates to the technical field of detection and provides an electron multiplier based detector. The electron multiplier based detector comprises a detection unit, a floating direct-current power supply U1 of the detection unit, a thermionic cathode, a floating power supply U2 of the thermionic cathode and a signal amplification unit, wherein the detection unit is connected with the thermionic cathode, the signal amplification unit consists of an accelerating field cathode plate, an electron multiplier, a charge collector electrode, a voltage divider power supply U3, a voltage divider resistor R1, a voltage divider resistor R2, a voltage divider resistor R3, a capacitor C3, a capacitor C4 and a capacitor C5, the floating direct-current power supply U1 constantly extracts electrons of an anode of the detection unit to the thermionic cathode, free electrons generated by the thermionic cathode are fed into the electron multiplier through an accelerating field, and amplified signal current reaches the charge collector electrode and then is output. The electron multiplier based detector can effectively amplify weak-current signals and is good in environmental adaption capacity.