Method of manufacturing electron multiplier body, photomultiplier tube, and photomultiplier

An electron multiplier body comprising:

• a main body portion including one end surface and the other end surface and formed in a rectangular parallelepiped shape extending in a first direction from the one end surface;
• a channel reaching from the one end surface to the other end surface, opened at the one end surface and the other end surface, and emitting secondary electrons according to incident electrons;
• a resistive layer and a secondary electron multiplication layer formed on an inner surface of the channel;
• and
• metal layers provided on the one end surface and the other end surface,
• wherein the main body portion is given a potential difference so that the metal layer provided on the other end surface has a higher potential than that of the metal layer provided on the one end surface,
• the channel includes an electron incidence portion provided in the main body portion to be opened at the one end surface,
• the main body portion includes a first plate-like member that has a hole portion defining the channel and that is divided into a plurality of parts by the hole portion, and a pair of second plate-like members configuring the channel by closing the hole portion,
• the first and second plate-like members are formed of a ceramic,
• the main body portion is constituted by laminating the first and second plate-like members on each other so that the first plate-like member is interposed between the pair of second plate-like members, and by sintering laminated the first and second plate-like members.