Patent ID: 8330364
Filing Date: 2012-12-11
Classification: H01J

Abstract:
1. A photomultiplier, comprising: a sealed container, an interior of which is depressurized to a predetermined degree of vacuum; a photocathode, housed inside the sealed container, emitting photoelectrons into the sealed container in response to light with a predetermined wavelength; an electron multiplier section, housed inside the sealed container, emitting secondary electrons in response to the photoelectrons arriving from the photocathode, and successively cascade multiplying the secondary electrons, the electron multiplier section including multiple stages of dynode units, each having one or more dynodes respectively set to a same potential and frame integrally supporting the dynodes; an anode, arranged inside the sealed container so as to sandwich the electron multiplier section together with the photocathode, capturing the secondary electrons emitted from the electron multiplier section; and a plurality of dynode pins for setting each of the multiple stages of dynode units to a predetermined potential, one end of each being fixed while being electrically connected to the associated one of the multiple stages of dynode units, wherein the electron multiplier includes, at least, a first dynode unit having a first dynode emitting secondary electrons in response to incidence of the photoelectrons emitted from the photocathode, a second dynode unit having a second dynode emitting secondary electrons in response to incidence of the secondary electrons emitted from the first dynode and a third dynode unit having a third dynode emitting secondary electrons in response to incidence of the secondary electrons emitted from the second dynode; and wherein the frames of the first to third dynode units are stacked sequentially from the photocathode toward the anode in a manner such that the frame of the first dynode unit is positioned between the frames of the second and third dynode units.