Amplifier, radiation detector, and radiation detector control method

An amplifier provided in a photon-counting radiation detector, the amplifier comprising:

• an inverting amplification unit that inverts and amplifies an input signal to generate an inverted amplified output a feedback transistor that connects an input unit and an output unit of the inverting amplification unit to each other;
• and
• a pulse measurement unit that generates an output signal corresponding to a number of pulses of the inverted amplified output, wherein
• the pulse measurement unit is capable of supplying the output signal toward the feedback transistor,
• in a case where the pulse measurement unit supplies the output signal toward the feedback transistor,
• the pulse measurement unit is connected to a gate of a second transistor,
• the second transistor is connected to a gate of the feedback transistor through a third transistor,
• at a point in time before the inverting amplification unit oscillates, the second transistor and the third transistor are switched on and a gate voltage of the feedback transistor increases according to a second voltage signal supplied to the second transistor,
• at a point in time when the gate voltage of the feedback transistor reaches an oscillation start value, the inverting amplification unit starts to oscillate,
• at a point in time after the inverting amplification unit starts to oscillate, the gate voltage of the feedback transistor is held at a first value larger than the oscillation start value by switching off the second transistor as the oscillation of the inverting amplification unit continues, and
• at a point in time after the gate voltage of the feedback transistor is held at the first value, the gate voltage of the feedback transistor is held at a second value smaller than the oscillation start value by extracting electric charge from the feedback transistor in accordance with a change in a third voltage signal supplied to the third transistor.