Patent 11139293 was granted and assigned to Hamamatsu Photonics on October, 2021 by the United States Patent and Trademark Office.
The present embodiment relates to a photon detector which includes a preamplifier having a structure capable of preventing saturation of an amplifier. The preamplifier includes an amplifier, and further includes a capacitive element, an n-type MOSFET, and a p-type MOSFET disposed on a plurality of wirings electrically connecting the input end side and the output end side of the amplifier. A control electrode of the n-type MOSFET is set to a first fixed potential V1, while a control electrode of the p-type MOSFET is set to a second fixed potential V2.