| 摘要 |
PROBLEM TO BE SOLVED: To improve cooling efficiency, while preventing the dispersion of heat used to extract cooling in a support member by supporting a support board with support board supporting projections provided in a notch part, so as to reduce a contact area of the support board with the support member. SOLUTION: In a side-on type cooling photomultiplier, a support board 5 formed with a photoelectric negative electrode material 4 in a surface thereof is cooled by a Peltier effect element provided in a vertex of a tube 1. An upper- end part of the support board 5 is cooled through a holding mechanism, and a central part and a lower end thereof are supported by the only four supporting projections provided in a notch part 10a of a first insulating board 10 and four supporting projections provided in a notch part of a second insulating board provided under the tube 1 and having the same shape as the projections of notch part 10a so that a contact area with both the insulating board is remarkably reduced. With this structure, dispersion of the cooling heat used to extract cooling by the Peltier effect element in the first insulating board 10 and the second insulating board is prevented, so as to effectively cool the photoelectric negative electrode material 4, and generation of thermoelectrons from a photoelectric surface is lowered. |
