Hamamatsu-photonics K.k.

Takehisa Okamoto

Makoto Nakamura

Haruhisa Yamaguchi

Shiro Sakai

Takayuki Ohmura

Tetsuya Morita

Hiroshi Suzuki

An ion detector includes an ion input face, a Faraday cup, an ion-to-electron converter dynode, two ion deflection electrodes, an electron multiplier portion, and an anode. The ion input face is formed with an ion input opening. The Faraday cup has an ion collection surface that confronts the ion input opening. The ion-to-electron converter dynode is disposed to one side with respect to the Faraday cup and the ion input opening and has a conversion surface that converts impinging ions into electrons. The two ion deflection electrodes generate an electron lens that attracts and focuses ions from the ion input opening toward the conversion surface of the ion-to-electron converter dynode. The electron multiplier portion receives and multiplies the electrons from the ion-to-electron converter dynode, and includes a plurality of dynodes that multiply electrons one after the other. The plurality of dynodes are juxtaposed in an arc-shape around the Faraday cup. The anode receives electrons from the electron multiplier portion and outputs a signal that corresponds to the amount of input ions.

Mass spectrometer and ion detector used therein

An electron multiplier according to this invention comprises dynodes DY1 .about.DY16 arranged in multi-stages along a direction of incidence of an energy beam for, upon incidence of the energy beam, gradually multiplying secondary electrons to emit the same, a collection electrode A for receiving electrons emitted from that of the dynodes on a last stage, and resistors R1 .about.R16 inserted between the respective dynodes and their adjacent ones, the dynodes, the collecting electrode, and the resistors being mounted between two support plates 10a, 10b disposed in parallel with each other, the resistors being arranged in two rows which sandwich the dynodes.

Electron multiplier

The electron multiplying device according to this invention comprises an electron multiplying unit including dynodes arranged in a plurality of stages. The electron multiplying unit has an incidence opening for an energy beam to be multiplied to enter through, and has the proximal end secured to a base. There is provided a casing for housing the electron multiplying unit. The forward edge of the casing is secured to the base, and a space defined by the base and the casing houses the electron multiplying unit. The casing has an entrance window formed at a position opposed to the incidence opening. Energy beams enter the electron multiplying unit through the entrance window, but the electron multiplying unit itself is housed in the casing to be protected from surrounding air flow and unnecessary energy beams not to be measured.

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Hamamatsu, Japan

Takehisa Okamoto