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US 3,941,998 AGranted
Optoelectronic sampling head
AssigneeUniversity of Illinois Foundation
InventorHenry Merkelo
Life of this patent
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AssigneeUniversity of Illinois Foundation
InventorHenry Merkelo
Estimating the term…
An electronic sampling head comprising a housing having a path for impinging radiation, a photoemissive element positioned across said path, photoelectron ejection means positioned in proximity to said photoemissive element, means for applying ultrashort sampling potential differences between said photoemissive element and said photoelectron ejection means for accelerating photoelectrons emitted by said photoemissive element in response to said incident radiation, and means for detecting said photoelectrons all resulting in the capability of detecting high-speed radiation phenomena with waveform fidelity.
A high speed sampling head for photoelectrons comprising a housing having a path for impinging radiation, a strip-shaped photoemissive element positioned across said path, planar photoelectron ejection means positioned in proximity to said photo-emissive element in said path, means for propagating a high speed sampling potential difference between said photoemissive element and said photoelectron ejection means, means for accelerating photoelectrons emitted by said photoemissive element in response to said incident radiation, and means for detecting said photoelectrons, whereby said ejection means constitute a microstrip ground plane for said photoemissive element.
An optoelectronic sampling head comprising a housing having an optical path for impinging light, a photoemissive elongated strip positioned across said optical path and supported in said housing by broadband insulated electrical feedthrough elements, an insert positionable in said housing, said insert including a photoelectron ejection ground plane and an electron path, and spacer means mounted to said insert and positioned with said insert against said housing for positioning said photoelectron ejection ground plane with predetermined spatial distance from said photoemissive strip.
An optoelectronic sampling head comprising a conductive housing defining an optical path in the axial direction of said housing for impinging light, a pair of diametrically opposite apertures in said housing, insulation means sealed in said apertures, electrical leads extending through said insulating means, an elongated photoemissive strip supported on said leads inside said housing, a conductive insert positioned within said housing and having affixed thereto a perforated photoelectron ejection ground plane normal to the axis of said housing, said ground plane being spaced from said elongated strip a distance up to 300 microns in the axial direction of said housing, and electron multiplier means affixed to said housing in the optical path on the end thereof toward said ground plane, whereby said ground plane constitutes a microstrip ground plane for said strip.
Dependencies are inferred from the claim text.
No related US applications are recorded in the indexed filing history.
Constructional features, e.g. arrangements of optical elements: of receivers alone
Secondary-emission tubes; Electron-multiplier tubes: tubes in which one or a few electrodes are secondary-electron emitting electrodes
Radio direction-finding
Electric discharge tubes or discharge lamps
Term ended 2 Mar 1993 (estimated)
USPTO file history isn’t available for this patent, so only indexed dates are shown.
This invention relates to optical detection devices and specifically to optical sampling heads usable in conjunction with photoelectron amplifying devices suitable for low power radiation detection.
A need exists for a high resolution sampling detector for detecting radiation levels, particularly optical, at relatively high sampling speeds. Since in many applications the photon flux level at high sampling speed will be low, a sensitive device for detection is required.
A conventional form of detection device is the photomultiplier. In its usual form, the single stage device employs a photocathode, emitting electrons in response to impinging radiation, a secondary emissive electrode or dynode, and a collector electrode or anode. In a multistage electron multiplier, a cascade of dynodes are employed, with successively higher biasing potentials, such that impinging primary electrons cause emission of secondary electrons in a multiplying progression from successive dynodes, and are ultimately collected by the anode which in turn provides an output signal.
The foregoing objects and brief description of the present invention will become more apparent from the following detailed description and appended drawings wherein
FIG. 1 shows the head of the present invention utilized with an electron multiplier;
FIG. 2 is a cross section along the optical path of the head showing the housing and photoemissive strip;
Referring to FIG. 1, sampling head 10 constructed in accordance with the present invention is shown in mounted position on a conventional electron multiplier 12. For purposes of illustration, the electron multiplier may be that of an RCA Model 7102 photo-tube including a dynode/anode structure 14 including a plurality of voltage leads 16 for applying a potential to the dynode/anode electrode structure 14. Other conventional electron multipliers may also be employed with the sampling head. The photo-tube 12 has been modified to the extent that an external source of electrons, supplied by the sampling head 10, may be provided. To this end, a flange 18 including mounting bolts 20 provides a support frame for mounting the head 10 to the tube 12. An O-ring seal 22 may be provided to vacuum and optically seal the head outlet to the tube inlet.
On the left side of the head 10, referring to FIG. 1, a lens or window unit 24 is bolted to the optical inlet side of the head 10. A further O-ring seal 26 may be used to vacuum seal the optical element through the head. The head is bolted by means of bolts 28 to the lens structure 24.
Incident radiation 30 impinges, through the lens 24, upon the photosensitive surface creating photoelectrons which are sampled by the head 10 in a manner to be set forth in further detail below, and the resulting electron flow multiplied in the electrode structure 14 of the electron multiplier 12.