In order to reduce an influence of disturbance propagation
noise inside and outside a
signal detection device and improve
signal detection accuracy, the present disclosure provides a
signal detection device including: detection equipment including a
photoelectric conversion element configured to convert a
photon as a detection target into a current signal, and a current-
voltage converter configured to convert the current signal into a
voltage signal; a transmission unit configured to transmit the
voltage signal; and a data collection unit configured to detect and collect the transmitted voltage signal. Here, the detection equipment is disposed inside a first shield case connected to a frame ground. The current-
voltage converter includes a
differential amplifier having first and second input terminals, the first input terminal is connected to a first output terminal of the
photoelectric conversion element via a first input
resistor, the second input terminal is connected to a second output terminal of the
photoelectric conversion element and a ground via a second input
resistor having a resistance value larger than that of the first input
resistor. First and second output terminals of the current-
voltage converter are connected to the data collection unit by a
cable transmission unit. The
cable transmission unit is connected to the ground together with the current-
voltage converter and the data collection unit (see FIG. 1).