Abstract:
A photomultiplier tube comprises an evacuated envelope including a faceplate and a sidewall. A conductive coating is disposed annularly around an interior portion of the sidewall adjacent to the faceplate and on a longitudinally extending portion of the sidewall as a strip. A photoemissive cathode is disposed on an interior surface of the faceplate and on the conductive coating adjacent thereto. A shield cup is spaced from the cathode and centered within the envelope by a plurality of bulb spacers. An electron multiplier cage assembly abuts the shield cup and is attached thereto. A cathode contact assembly is in contact with the strip on the sidewall. A plurality of locating slots are formed in the base of the shield cup to orient the bulb spacers in contact with the sidewall of the envelope and spaced from the longitudinally extending strip portion of the conductive coating thereon. The bulb spacers include stop shoulders which retain the bulb spacers within the locating slots. The cathode contact assembly includes a cathode contact support member and a resilient cathode contact member. The cathode contact support member includes an electrical contact tab struck from the body thereof and a cathode support tab which includes an extruded area to circumferentially locate the resilient cathode contact member between two consecutively spaced bulb spacers and to align the resilient cathode contact member with the longitudinally extending strip portion of the conductive coating on the sidewall of the envelope.
Abstract:
A photomultiplier tube comprises an evacuated envelope having a photoemissive cathode, a shield cup spaced from the cathode and an electron multiplier cage assembly abutting the shield cup. The cage assembly includes a pair of transversely spaced support plates having a plurality of support slots formed therethrough. Each of the support plates has a distal end and a proximal end, with the proximal ends being attached to the shield cup. A light shield is disposed between the distal end of the support plates. An anode and a plurality of dynodes, at least one of which has a field mesh attached thereto, are disposed between the support plates and attached thereto by end tabs. The end tabs extend from the side of the anode and the dynodes. The aforementioned shield cup includes flaps which establish a minimum transverse spacing between the proximal ends of the support plates. The light shield has a transverse dimension substantially equal to that of the flaps to establish a minimum transverse spacing between the distal end of the support plates. The flaps and the light shield thus act, in combination, to provide a uniform minimum transverse spacing between the support plates which is greater than the transverse dimension of the anode and the dynodes to prevent distortion of the field mesh. The tab ends of the dynode and the anode are bifurcated so that one portion of selected ones of the tab ends can be formed to secure the dynodes and the anode between the support plates.
Abstract:
The improved photomultiplier tube utilizes a multi-channel structure within a common envelope. A photocathode and a plurality of dynode members each have barrier means associated therewith to effect a plurality of related-area elements on each member providing a plurality of separate photomultiplier channel areas thereon. The anode structure has a separate anode element for each individual channel with a separate electrical connection extending therefrom. The photocathode and the separate dynode members each have individual electrical connections which are common to the related channel areas respectively formed thereon.
Abstract:
An electron multiplier used together with additional elements to form a simple spectrometer for mass distribution studies. The multiplier is used to multiply a few electrons to provide an electron cascade at the multiplier output end which provides a trigger pulse, serving as a time reference and to ionize molecules at the output end. The multiplier serves as a path for positive ions which accelerate towards the multiplier''s input end, whereat they collide with a surface to produce secondary electrons, which are then multiplied by the multiplier as they accelerate to the output end to provide output pulses, whose time displacements from the trigger are indicative of the mass to charge ratio of the created ions.
Abstract:
In-situ methods for the batch fabrication of flat-panel micro-channel plate (MCP) photomultiplier tube (PMT) detectors (MCP-PMTs), without transporting either the window or the detector assembly inside a vacuum vessel are provided. The method allows for the synthesis of a reflection-mode photocathode on the entrance to the pores of a first MCP or the synthesis of a transmission-mode photocathode on the vacuum side of a photodetector entrance window.
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 surface 401 and having a notched part 35 at a site opposing the electron multiplying parts 33 on the second end side.
Abstract:
The invention provides a device for introducing ions into the primary ion path of a mass spectrometry system. In general, the device contains an electrical lens having a primary ion passageway and a secondary ion passageway that merges with the primary ion passageway. In certain embodiments, the electrical lens contains a first part and a second part that, together, form the primary ion passageway. The first part of the lens may contain the secondary ion passageway.
Abstract:
A photomultiplier eliminates the reflection of light off of focusing pieces in a focusing electrode and prevents the photocathode from emitting useless electrons in response to such reflected light by including an oxide film formed over the surface of each focusing piece. The oxide film is also formed on the surface of secondary electron emission pieces in the first and second stage dynodes to eliminate the reflection of light off of the secondary electron emission pieces and to prevent the photocathode from emitting useless electrons in response to such reflected light. Further, a light-absorbing glass partitioning part is provided in a light-receiving faceplate to suppress crosstalk between channels.