Abstract: One or more embodiments relates to a system and method for growing ultrasmooth and high quantum efficiency photocathodes. The method includes exposing a substrate of Si wafer to an alkali source; controlling co-evaporating growth and co-deposition forming a growth including Te; and monitoring a stoichiometry of the growth, forming the photocathodes.

Abstract: An ultraviolet flame detector (100) includes a housing (102) having an opening (103) at a first end (101a) of the housing (102), and a window structure (104) arranged to cover the opening (103) of the housing (102). A photocathode (106) is arranged to a second end (101b) of the housing (102) so that the photocathode (106) is facing inside the housing (102). An anode wire (108) is arranged between the window structure (104) and the photocathode (106). The anode wire (108) is configured to travel transversally across the housing (102). The ultraviolet flame detector (102) is filled with a gas.

Abstract: Disclosed herein is a semiconductor device including a light emitting structure including a first conductive type semiconductor layer, a plurality of active layers disposed to be spaced apart on the first conductive type semiconductor layer, and a plurality of second conductive type semiconductor layers disposed on the plurality of active layers, respectively, a first electrode electrically connected to the first conductive type semiconductor layer, and a plurality of second electrodes electrically connected to the plurality of second conductive type semiconductor layers, respectively, wherein the plurality of active layers include a first active layer, a second active layer, and a third active layer, the light emitting structure includes a first light emitter including the first active layer, a second light emitter including the second active layer, and a third light emitter including the third active layer, the first active layer emits light in a blue wavelength band, the second active layer emits light in

Abstract: A photocathode assembly may include: a reflective substrate; an enhancement layer on the reflective substrate; and a photosensitive film on the enhancement layer, wherein the enhancement layer has a thickness of about 10 nm or less.

Abstract: Disclosed herein is a photomultiplier tube (PMT) comprising: an electron ejector configured for emitting primary electrons in response to an incident photon; a detector configured for collecting electrons and providing an output signal representative of the incident photon; and a series of electrodes between the electron ejector and the detector, wherein each of the electrodes is configured for emitting secondary electrons in response to incident electrons, and each of the electrodes includes a bi-metal arc-shaped sheet.

Abstract: According to an embodiment of the present disclosure, a photocathode may include: a mesh having a first surface and a second surface facing away from the first surface, and including metallic, semiconductor or ceramic mesh grid with micron-sized openings in the mesh; a photosensitive film on the first surface of the mesh and extending at least partially into the openings of the mesh; and a graphene layer including one or more graphene sheets on the second surface of the mesh.

Abstract: The invention provides a lighting device comprising a light source and a light converter, wherein the light source is configured to provide light source light, wherein the light converter comprises a donor luminescent material able to convert at least part of the first light source light into donor light, and a acceptor luminescent material, wherein the donor luminescent material and acceptor luminescent material are configured as donor-acceptor luminescent materials which, upon excitation of the donor luminescent material by the light source light provide acceptor light having an acceptor light spectral distribution different from a donor light spectral distribution of the donor light, wherein the light converter further comprises a periodic plasmonic antenna array configured to enhance generation of said donor light, and wherein the lighting device is configured to provide lighting device light comprising said donor light and said acceptor light.

Abstract: Provided are a field emission device and a method of manufacturing the same. The field emission device includes an anode electrode and a cathode electrode which are opposite to each other, a counter layer provided on the anode electrode, and a field emitter provided on the cathode electrode and facing the counter layer. Herein, the field emitter includes a carbon nanotube emitting cold electrons and a photoelectric material emitting photo electrons.

Abstract: A photon sensing and amplification device including a photocathode, a transparent electrode opposed from the photocathode, and a plasma chamber positioned between the photocathode and the transparent electrode, wherein the plasma chamber houses an ionizable gas.

Abstract: Disclosed are graphene shield enhanced photocathodes, such as high QE photocathodes. In certain embodiments, a monolayer graphene shield membrane ruggedizes a high quantum efficiency photoemission electron source by protecting a photosensitive film of the photocathode, extending operational lifetime and simplifying its integration in practical electron sources. In certain embodiments of the disclosed graphene shield enhanced photocathodes, the graphene serves as a transparent shield that does not inhibit photon or electron transmission but isolates the photosensitive film of the photocathode from reactive gas species, preventing contamination and yielding longer lifetime.

Abstract: A photo cathode for use in a vacuum tube including a cathode layer, having an entrance face capable of absorbing photons impinging on the cathode layer, and an exit face for releasing electrons upon impinging of the photons, and an electron exit layer, in facing relationship with the exit face of the cathode layer for improving the releasing of the electrons, and a carbon containing layer, positioned between the exit face of the cathode layer and the electron exit layer, for bonding the electron exit layer to the cathode layer.

Abstract: The present invention aims at providing a photocathode which can improve various characteristics. In a photocathode 10, an intermediate layer 14, an underlayer 16, and a photoelectron emission layer 18 are formed in this order on a substrate 12. The photoelectron emission layer 18 contains Sb and Bi and functions to emit a photoelectron in response to light incident thereon. The photoelectron emission layer 18 contains 32 mol % or less of Bi relative to SbBi. This can dramatically improve the linearity at low temperatures.

Abstract: Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for H2 production from water splitting half-reaction.

Abstract: A low-workfunction photocathode includes a photoemissive material employed as a coating on the photocathode. The photoemissive material includes AnMC2, where A is a first metal element, the first element is an alkali metal, an alkali-earth element or the element Al; n is an integer that is 0, 1, 2, 3 or 4; M is a second metal element, the second metal element is a transition metal or a metal stand-in; and C2 is the acetylide ion C22?. The photoemissive material includes a crystalline structure or non-crystalline structure of rod-like or curvy 1-dimensional polymeric substructures with MC2 repeating units embedded in a matrix of A.

Abstract: A photoelectric cathode has a work function lowering material such as cesium placed into an enclosure which couples a thermal energy from a heater to the work function lowering material. The enclosure directs the work function lowering material in vapor form through a low diffusion layer, through a free space layer, and through a uniform porosity layer, one side of which also forms a photoelectric cathode surface. The low diffusion layer may be formed from sintered powdered metal, such as tungsten, and the uniform porosity layer may be formed from wires which are sintered together to form pores between the wires which are continuous from the a back surface to a front surface which is also the photoelectric surface.

Abstract: Disclosed herein is a PhotoMultiplier Tube (PMT) designed for use with a surface inspection system such as the Surfscan system, which operates at 266 nm wavelength. The inventive PMT is high efficiency, low noise, and low gain, a combination of features that is specific to the application and contrary to the features of PMT's in the art. The inventive PMT is designed to be tuned to a specific narrow band wavelength of incident light, thereby optimizing the QE at that wavelength. It is further designed to combine a small number of dynodes each having substantially higher secondary electron gain than typical dynodes. By designing the PMT in this way, the excess noise factor is dramatically reduced, yielding a much improved S/N, while still maintaining the overall PMT gain in the lower range suitable for use in a surface inspection system.

Abstract: Disclosed are graphene shield enhanced photocathodes, such as high QE photocathodes. In certain embodiments, a monolayer graphene shield membrane ruggedizes a high quantum efficiency photoemission electron source by protecting a photosensitive film of the photocathode, extending operational lifetime and simplifying its integration in practical electron sources. In certain embodiments of the disclosed graphene shield enhanced photocathodes, the graphene serves as a transparent shield that does not inhibit photon or electron transmission but isolates the photosensitive film of the photocathode from reactive gas species, preventing contamination and yielding longer lifetime.

Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.

Abstract: A photo cathode for use in a vacuum tube including a cathode layer, having an entrance face capable of absorbing photons impinging on the cathode layer, and an exit face for releasing electrons upon impinging of the photons, and an electron exit layer, in facing relationship with the exit face of the cathode layer for improving the releasing of the electrons, and a carbon containing layer, positioned between the exit face of the cathode layer and the electron exit layer, for bonding the electron exit layer to the cathode layer.

Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.

Abstract: 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.

Abstract: The photomultiplier tube 1 is provided with an upper frame 2 and a lower frame 4 which are arranged so as to oppose each other, with the respective opposing surfaces 20a, 40a made with an insulating material, a side wall part 3 which constitutes a casing together with the frames 2, 4, a plurality of stages of electron multiplying parts 33 which are arrayed so as to be spaced away sequentially from a first end side to a second end side on the opposing surface 40a of the lower frame 4, a photocathode 41 which is installed on the first end side so as to be spaced away from the electron multiplying parts 33, converting incident light from outside to photoelectrons, an anode part 34 which is installed on the second end side so as to be spaced away from the electron multiplying parts 33 to take out electrons multiplied by the electron multiplying parts 33 as a signal, and a wall-like electrode 32 which is arranged so as to enclose the photocathode 41 when viewed from a direction directly opposite to an opposing sur

Abstract: A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

Abstract: A photomultiplier tube including a photocathode, an electron multiplier, an electron collector, and a power lead, wherein the photocathode and the electron multiplier are disposed in a sealed transparent vacuum envelope, the electron collector and the power lead are connected with an external circuit outside the vacuum envelope, the photocathode is formed on the entire inner surface of the vacuum envelope, and the electron multiplier is located on the internal center of the vacuum envelope to receive photoelectrons from the photocathode in all directions for electrons multiplication. Because the effective photocathode area is increased, the detection efficiency of unit light-receiving area is improved.

Abstract: A monitor that can detect at least one molecule. The monitor includes a housing with a passage that can receive a sample, and a photocathode that is located within the housing. The monitor also includes a first ultraviolet light source that can direct ultraviolet light onto the photocathode to create electrons that ionize molecules within the sample, and a detector that is coupled to the housing to detect at least one ionized molecule. The monitor enables electron ionization (EI) of a sample for chemical analysis without the disadvantages of current methods that use a hot filament or other thermal cathode devices.

Abstract: A method for fabrication of substrate having a nano-scale surface roughness is presented. The method comprises: patterning a surface of a substrate to create an array of spaced-apart regions of a light sensitive material; applying a controllable etching to the patterned surface, said controllable etching being of a predetermined duration selected so as to form a pattern with nano-scale features; and removing the light sensitive material, thereby creating a structure with the nano-scale surface roughness. Silanizing such nano-scale roughness surface with hydrophobic molecules results in the creation of super-hydrophobic properties characterized by both a large contact angle and a large tilting angle. Also, deposition of a photo-active material on the nano-scale roughness surface results in a photocathode with enhanced photoemission yield. This method also provides for fabrication of a photocathode insensitive to polarization of incident light.

Abstract: An electron source includes a back contact surface having a means for attaching a power source to the back contact surface. The electron source also includes a layer comprising platinum in direct contact with the back contact surface, a composite layer of single-walled carbon nanotubes embedded in platinum in direct contact with the layer comprising platinum. The electron source also includes a nanocrystalline diamond layer in direct contact with the composite layer. The nanocrystalline diamond layer is doped with boron. A portion of the back contact surface is removed to reveal the underlying platinum. The electron source is contained in an evacuable container.

Abstract: An electron tube of the present invention includes: a vacuum vessel including a face plate portion and a stem portion arranged facing the face plate portion; a photocathode arranged in the vacuum vessel and formed on the face plate portion; a projection portion arranged in the vacuum vessel, extending from the stem portion toward the face plate portion, and made of an insulating material; an electron detector arranged on the projection portion, made of a semiconductor, and having a first conductivity-type region and a second conductivity-type region; and a first conductive film covering a surface of the projection portion and to be electrically connected to the first conductivity-type region.

Abstract: Exemplary embodiments are disclosed of anti-reflective nanoporous silicon for efficient hydrogen production by photoelectrolysis of water. A nanoporous black Si is disclosed as an efficient photocathode for H2 production from water splitting half-reaction.

Abstract: The present invention relates to a photomultiplier having a structure for making it possible to easily realize high detection accuracy and fine processing, and a method of manufacturing the same. The photomultiplier comprises an enclosure having an inside kept in a vacuum state, whereas a photocathode emitting electrons in response to incident light, an electron multiplier section multiplying in a cascading manner the electron emitted from the photocathode, and an anode for taking out a secondary electron generated in the electron multiplier section are arranged in the enclosure. A part of the enclosure is constructed by a glass substrate having a flat part, whereas each of the electron multiplier section and anode is two-dimensionally arranged on the flat part in the glass substrate.

Abstract: A spark gap switch for controlling the output of a high voltage pulse from a high voltage source, for example, a capacitor bank or a pulse forming network, to an external load such as a high gradient electron gun, laser, pulsed power accelerator or wide band radar. The combination of a UV laser and a high vacuum quartz cell, in which a photocathode and an anode are installed, is utilized as triggering devices to switch the spark gap from a non-conducting state to a conducting state with low delay and low jitter.

Abstract: A photocathode for an image intensifier tube includes a faceplate, a glass plate disposed opposite the faceplate, and a span having one end attached to the glass plate and the other end attached to the faceplate for forming a sealed chamber between the faceplate and the glass plate. A semiconductor layer is bonded to a surface of the glass plate, where the surface is disposed outside of the sealed chamber. The semiconductor layer forms a photocathode. A thermal electric cooler (TEC) is disposed inside the sealed chamber for cooling the photocathode. The faceplate is formed from sapphire material. The glass plate is formed from high conductivity glass. The span is formed from either high conductivity glass or low conductivity glass. The faceplate and the glass plate form a path for light to impinge upon the semiconductor layer, and the photocathode of the semiconductor layer is configured to convert the light into electrons for emission toward an electron gain device.

Abstract: The present invention aims at providing a photocathode which can improve various characteristics. In a photocathode 10, an intermediate layer 14, an underlayer 16, and a photoelectron emission layer 18 are formed in this order on a substrate 12. The photoelectron emission layer 18 contains Sb and Bi and functions to emit a photoelectron in response to light incident thereon. The photoelectron emission layer 18 contains 32 mol % or less of Bi relative to SbBi. This can dramatically improve the linearity at low temperatures.

Abstract: The present invention relates to a photomultiplier having a fine structure capable of realizing high detection accuracy by effectively suppressing cross talk among electron-multiplier channels. The photomultiplier comprises a housing whose inside is maintained vacuum, and, in the housing, a photocathode, an electron-multiplier section, and anodes are disposed. The electron-multiplier section has groove portions for cascade-multiplying photoelectrons as electron-multiplier channels, and the anodes are constituted by channel electrodes corresponding to the groove portions respectively defined by wall parts. In particular, at least parts of the respective channel electrodes are located in spaces sandwiched between pairs of wall parts defining the corresponding groove portions.

Abstract: A method for fabrication of substrate having a nano-scale surface roughness is presented. The method comprises: patterning a surface of a substrate to create an array of spaced-apart regions of a light sensitive material; applying a controllable etching to the patterned surface, said controllable etching being of a predetermined duration selected so as to form a pattern with nano-scale features; and removing the light sensitive material, thereby creating a structure with the nano-scale surface roughness. Silanizing such nano-scale roughness surface with hydrophobic molecules results in the creation of super-hydrophobic properties characterized by both a large contact angle and a large tilting angle. Also, deposition of a photo-active material on the nano-scale roughness surface results in a photocathode with enhanced photoemission yield. This method also provides for fabrication of a photocathode insensitive to polarization of incident light.

Abstract: A semiconductor photocathode 1 includes: a transparent substrate 11; a first electrode 13, formed on the transparent substrate 11 and enabling passage of light that has been transmitted through the transparent substrate 11; a window layer 14, formed on the first electrode 13 and formed of a semiconductor material with a thickness of no less than 10 nm and no more than 200 nm; a light absorbing layer 15, formed on the window layer 14, formed of a semiconductor material that is lattice matched to the window layer 14, is narrower in energy band gap than the window layer 14, and in which photoelectrons are excited in response to the incidence of light; an electron emission layer 16, formed on the light absorbing layer 15, formed of a semiconductor material that is lattice matched to the light absorbing layer 15, and emitting the photoelectrons excited in the light absorbing layer 15 to the exterior from a surface; and a second electrode 18, formed on the electron emission layer.

Abstract: A vacuum vessel is configured by hermetically joining a faceplate to one end of a side tube and a stem to the other end via a tubular member. A photocathode, a focusing electrode, dynodes, a drawing electrode, and anodes are arranged within the vacuum vessel. The dynodes and the anodes have a plurality of channels in association with each other. Each electrode has cutout portions that overlap in a stacking direction, and supporting pins and lead pins are arranged in the cutout portions. A bridge is provided in a concave section arranged between unit anodes, and the bridge is cut off after the anode plate is placed on stem pins. Effective areas of each electrode and the anode are secured sufficiently, thereby allowing electrons to be detected efficiently.

Abstract: In the photocathode, an underlayer made of a crystalline material containing La2O3 is 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 e— generated within the photoelectron emission layer, photoelectrons traveling toward the supporting substrate side to the side opposite thereto.

Abstract: A multifunction module for an electron beam column comprises upper and lower electrodes, and a central ring electrode. The upper and lower electrodes have multipoles and are capable of deflecting, or correcting an aberration of, an electron beam passing through the electrodes. A voltage can be applied to the central ring electrode independently of the voltages applied to the upper and lower electrodes to focus the electron beam on a substrate.

Abstract: When to-be-detected light is made incident from a support substrate 2 side of a photocathode E1, a light absorbing layer 3 absorbs this to-be-detected light and produces photoelectrons. However, depending on the thickness and the like of the light absorbing layer 3, the to-be-detected light can be transmitted through the light absorbing layer 3 without being sufficiently absorbed by the light absorbing layer 3. The to-be-detected light transmitted through the light absorbing layer 3 reaches an electron emitting layer 4. A part of the to-be-detected light that has reached the electron emitting layer 4 proceeds toward a through-hole 5a of a contact layer 5. Since the length d1 of a diagonal line of the through-hole 5a is shorter than the wavelength of the to-be-detected light, the to-be-detected light can be suppressed from passing through the through-hole 5a and being emitted to the exterior.

Abstract: The present invention relates to an alkali metal generating agent and others for formation of a photo-cathode or a secondary-electron emitting surface capable of stably generating an alkali metal. The alkali metal generating agent is used in formation of a photo-cathode for emitting a photoelectron corresponding to incident light, or in formation of a secondary-electron emitting surface for emitting secondary electrons corresponding to an incident electron. Particularly, the alkali metal generating agent contains at least an oxidizer comprising at least one vanadate with an alkali metal ion as a counter cation, and a reducer for reducing the ion. An alkali metal generating device comprises at least the alkali metal generating agent and a case housing it, and the case is provided with a discharge port for discharging the vapor of the alkali metal.

Abstract: A photomultiplier tube 1 is an electron tube comprising an envelope 5 including a frame 3b having at least one end part formed with an opening and an upper substrate 2 airtightly joined to the opening, and a photocathode 6 contained within the envelope 5, the photocathode 6 emitting a photoelectron into the envelope 5 in response to light incident thereon from the outside; wherein multilayer metal films 10b, 10a each constituted by a metal film made of titanium, a metal film made of platinum, and a metal film made of gold laminated in this order are formed at the opening and the joint part between the upper substrate 2 and opening; and wherein the frame 3b and upper side substrate 2 are joined to each other by holding a joint layer 14 containing indium between the respective multilayer metal films 10b, 10a.

Abstract: When light is incident to an antenna layer AA6 of a photocathode AA1, light of a specific wavelength included in the incident light couples with surface plasmons in the antenna layer AA6 whereupon near-field light is outputted from a through hole AA14. The intensity of the output near-field light is proportional to and greater than the intensity of the light of the specific wavelength. The output near-field light has a wavelength that can be absorbed in a photoelectric conversion layer AA4. The photoelectric conversion layer AA4 receives the near-field light outputted from the through hole AA14. A region of the photoelectric conversion layer AA4 around the through hole AA14 absorbs the near-field light and generates photoelectrons (e?) in an amount according to the intensity of the near-field light. The photoelectrons (e?) generated in the photoelectric conversion layer AA4 are outputted to the outside.

Abstract: An optoelectronic modulator is based on the concentration of an electron beam from an electron gun by a tapered cavity, which sides are photosensitive and change the electrical conductivity under the illumination of light (electromagnetic radiation). The light modulation causes the corresponding changes in the current transported across the walls of the cavity. The remaining part of the electron current exits the cavity aperture and forms an amplitude-modulated divergent electron beam.

Abstract: An ion detector includes collision surfaces for converting both positively and negatively charged ions into emitted secondary electrons. Secondary electrons may be detected using an electron detector, than may, for example include an electron multiplier. Conveniently, secondary electrons (or electrons emitted by the multiplier) may be detected using an electron pulse counter.

Abstract: A viewing system configured to combine multiple spectral images of a scene, the system includes a spectral beam separator configured to split an incoming beam of radiation into a first and a second beam of radiation, the first beam of radiation including radiations substantially in a first spectral band and the second beam of radiation including radiations substantially in a second spectral band; an image intensifier configured to intensify the second beam of radiation, the image intensifier including a photocathode configured to produce a flux of photoelectrons with substantially increased efficiency when exposed to the second beam of radiation, the photocathode constructed and arranged to substantially absorb all the radiations in the second beam of radiation; a current amplifier configured to amplify the flux of photoelectrons; and a display system configured to display an image of the scene in the second spectral band based on the amplified flux of electrons simultaneously with an image of the scene in th

Abstract: 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.

Abstract: An envelope has a glass bulb body and a cylindrical glass bulb base. The glass bulb body includes an upper hemisphere and a lower hemisphere. The upper hemisphere is curved in a substantially spherical shape. The lower hemisphere is substantially curved in a spherical shape and connects the upper hemisphere and glass bulb base. A photocathode is formed on the inner surface of the glass bulb body. An avalanche photodiode is disposed on the glass bulb body side relative to an intersection between an imaginary extended curved surface of the lower hemisphere within the glass bulb base and an axis. When light enters the photocathode, electrons are emitted from the photocathode. The electrons are converged at the position above and in the vicinity of the APD by an electrical field in the electron tube, so that the electrons enter the APD in an efficient manner and are detected satisfactorily.

Abstract: A large area hybrid photomultiplier tube that includes a photocathode for emitting photoelectrons in correspondence with incident light, a semiconductor device having an electron incident surface for receiving photoelectrons from the photocathode, and a cone shaped container. The container has a first opening and a second opening. The photocathode is disposed at the first opening, and the semiconductor device is disposed at the second opening.

Abstract: An extension line of a tube axis of a photomultiplier tube is shifted from the center of gravity position of a front surface of a housing, which allows a space to be formed at an opposite side in the housing. A signal processing board is arranged in this space, and a high-voltage generating circuit board is fixed on the extension line of the tube axis, and thus the interior space of a housing can be effectively used. Since the signal processing board can be made adjacent to a tube wall of the photomultiplier tube, even when the length in a tube axis direction of the signal processing board is long, it becomes possible to house the same in the housing. Therefore, it becomes possible to achieve miniaturization.