Hamamatsu-photonics K.k.

Shinichi Yamashita

Satoshi Suzuki

Kengo Suzuki

Hiroyuki Watanabe

Kuniyoshi Mori

Daichi Masuko

Rina Konno

Fumio Watase

Hiroshi Komiyama

Yoshitaka Torii

Terunori Kawai

Masami Shibayama

Taisuke Nakaya

Hideaki Suzuki

Provided is a photomultiplier tube including: a container including a window portion formed of a light-transmitting material, and a tubular portion that is connected to the window portion and defines a vacuum space in combination with the window portion; a photoelectric surface that is formed of a photoelectron-emitting material consisting of sodium, potassium, and antimony, is provided on a first surface of the window portion on a side of the vacuum space, and emits photoelectrons in correspondence with incident light; and an electron multiplier that emits secondary electrons in correspondence with incidence of the photoelectrons emitted from the photoelectric surface, and multiplies the secondary electrons. An aluminum oxide layer is formed between the photoelectric surface and the window portion and on a surface of the tubular portion.

Photomultiplier tube including a protective layer

A photocathode including a substrate, a photoelectric conversion layer provided on the substrate and generating photoelectrons in response to incidence of light, and an underlayer provided between the substrate and the photoelectric conversion layer and containing beryllium, in which the underlayer has a first underlayer containing a nitride of beryllium.

Photocathode, electron tube, and method for manufacturing photocathode

The present invention relates to a photocathode having a structure to dramatically improve the effective quantum efficiency in comparison with that of a conventional art, an photomultiplier and an electron tube. The photocathode comprises a supporting substrate transmitting or blocking an incident light, a photoelectron emitting layer containing an alkali metal provided on the supporting substrate, and an underlayer provided between the supporting substrate and the photoelectron emitting layer. Particularly, the underlayer contains a beryllium oxide, and is adjusted in its thickness such that a thickness ratio of the underlayer to the photoelectron emitting layer falls within a specific range. This structure allows to obtain a photocathode having a dramatically improved quantum efficiency.

Photocathode, photomultiplier and electron tube

In the photocathode, an underlayer made of a crystalline material containing LaOis provided between a supporting substrate and a photoelectron emission layer, and is in contact with the photoelectron emission layer. Therefore, for example, at the time of heat treatment in a manufacturing process of the photocathode, dispersion to the supporting substrate side of an alkali metal contained in the photoelectron emission layer is suppressed. Further, it is assumed that this underlayer functions so as to reverse the direction of, out of photoelectrons egenerated within the photoelectron emission layer, photoelectrons traveling toward the supporting substrate side to the side opposite thereto.

Photocathode, electron tube, and photomultiplier tube

Growing community of inventors

Shizuoka, Japan

Shinichi Yamashita