Interaction depth of photons in a CdZnTe pixel detector is measured by configuring an ASIC connected to the detector to measure both positive polarity and negative polarity signal amplitudes and then measuring a core pixel having positive signal amplitude and hallow pixels having negative signal amplitude and surrounding the core pixel. When a thin semiconductor film with a thickness of 1 m or less is formed over the surface, minute convex portions are formed, which causes a problem that characteristics of TFTs vary among elements. The stem extends perpendicularly from the center of the elongated member and is substantially of the same length of the second hole. The handle and actuator can be operable with a single hand, such that the operation of the end effector can be accomplished with the same hand that is used to hold the handle and advance the end effector through an endoscope.