Use of flat panel microchannel photomultipliers in sampling calorimeters with timing

A detector comprising:

• at least one substantially planar slab of radiation-creating material;
• and
• at least one substantially planar photodetector, the at least one substantially planar photodetector comprising:
• a window having an inside surface;
• one or more microchannel plates;
• a dielectric base plate having in inside surface;
• an electrically conductive coating on the inside surface of the base plate;
• a first spacer or first set of spacers separating the window from the one or more microchannel plates;
• a second spacer or second set of spacers separating the one more microchannel plates from the dielectric base plate;
• and
• if the photodetector comprising more than one microchannel plate, a third spacer or third set of spaces separating the microchannel plates;
• and
• a dielectric side frame hermetically sealed between the window and the dielectric base plate to form a vacuum volume in which the one or more microchannel plates and the spacers are disposed, wherein the seal between the dielectric side frame and the dielectric base plate comprises a frit seal.