Photodetecting device and image sensing apparatus using the same

A photodetecting device comprising:

• a photodetecting section having a photoelectric surface for emitting photoelectrons upon incidence of light, a semiconductor detection element having an electron incident surface on which the photoelectrons can be incident, and a vacuum vessel in which said photoelectric surface is arranged on one inner surface, said semiconductor detection element being arranged on another inner surface opposing said one inner surface;
• cooling means for cooling a structure on said semiconductor detection element side of said vacuum vessel, said cooling means having a heat absorption portion for absorbing heat and a heat generation portion for generating heat, said heat absorption portion being arranged on said semiconductor detection element side of said vacuum vessel;
• and
• a housing which comprises a transparent portion capable of passing the light to be incident on said photoelectric surface, and a voltage introduction terminal capable of supplying, to said photodetecting section, a voltage to be applied between said photoelectric surface and said electron incident surface, and accommodates at least part of said vacuum vessel, wherein said heat generation portion of said cooling means is fixed at a predetermined position on an inner surface of said housing, and said heat absorption portion is disposed between said vacuum vessel and said housing such that heat from said semiconductor detection element and heat from said photoelectric surface are absorbed by said heat absorption portion through said vacuum vessel.