Device for measuring extremely diminished intensity of light

• US 4,611,920 A
• Filed: 09/14/1983
• Issued: 09/16/1986
• Est. Priority Date: 09/28/1982
• Status: Expired

• Current Assignee: Hamamatsu Photonics KK
• Original Assignee: Hamamatsu Photonics KK
• Inventors: Tsuchiya, Yutaka
• Primary Examiner(s): Evans, F. L.
• Assistant Examiner(s): NOT, DEFINED
• Application Number:
  US06/532,055
• Time in Patent Office: 1,098 Days
• Field of Search: 356/317, 356/318, 250/213 VT, 313/105 CM, 358/93, 358/209, 358/211, 358/217
• US Class Current: 356/318
• CPC Class Codes: G01J 1/42 using electric radiation detectors optical or mechanical part G01J1/04; by comparison with a reference light or electric value G01J1/10
• CPC Class Codes: G01J 2001/4238 Pulsed light
• CPC Class Codes: G01N 21/64 Fluorescence; Phosphorescence
• CPC Class Codes: H01J 31/502 with means to interrupt the beam, e.g. shutter for high speed photography circuits using electron-beam shutters G03B27/725

Abstract

A device for measuring an extremely diminished intensity of light by superposing a plurality of streaking images of the light beams caused by fluorescence occurring in a phosphor layer where secondary electrons are incident thereon in single photon units. A streaking image is formed by secondary electrons generated within a streaking tube through which electrons generated in a photoelectric layer therein are accelerated to the phosphor layer therein when passing through a micro-channel-plate therein. The superposed streaking images with enhanced brightness are then picked up by a television camera.

Claims

1. A device for measuring an extremely diminished intensity of light comprising:

a stimulus signal source which stimulates an object being measured so as to repetitively emit light pulses at predetermined timing intervals;

a streaking tube including

a photoelectric layer for converting said repetitive light pulses to corresponding electric signals;

a deflection electrode for generating a deflection electric field for deflecting a single photoelectron;

a micro-channel-plate consisting of curved micro-channels for multiplying said single photoelectron so as to generate a plurality of electrons at the output thereof, the distribution of said electrons having a narrow half-value centered at a predetermined frequency of occurrence;

a phosphor layer stimulated by electrons at the output of said micro-channel-plate, a spot having approximately the same brightness for each of said single photoelectrons being formed on the surface of said phosphor layer whereby the brightness of said spot corresponds to the number of multiplied electrons;

a deflection circuit for applying, to said deflection electrode, a sweeping voltage synchronized with the stimulating signal issued from said stimulus signal source; and

detecting means for detecting the brightness of said spot on the phosphor layer of said streaking tube by means of photoelectric conversion, said detecting means being a television imaging device wherein the horizontal trace thereof extends orthogonally to the direction of deflection of said streaking tube.

2. A device for measuring an extremely diminished intensity of light as claimed in claim 1, wherein said stimulus signal source is a dye laser oscillator.