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Topic: Photomultiplier


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In the News (Wed 24 Jul 19)

  
  Olympus Microscopy Resource Center: Photomicrography - Interactive Flash Tutorials - Photomultiplier Tubes
A photomultiplier tube, useful for light detection of very weak signals, is a photoemissive device in which the absorption of a photon results in the emission of an electron.
Photomultipliers acquire light through a glass or quartz window that covers a photosensitive surface, called a photocathode, which then releases electrons that are multiplied by electrodes known as metal channel dynodes.
Photomultipliers produce a signal even in the absence of light due to dark current arising from thermal emissions of electrons from the photocathode, leakage current between dynodes, as well as stray high-energy radiation.
www.olympusmicro.com /primer/flash/photomultiplier   (611 words)

  
 Photomultiplier - Wikipedia
Photomultiplier sind spezielle Elektronenröhren um schwache Lichtsignale (bis hin zu einzelnen Photonen) zu verstärken und in ein elektrisches Signal umzuwandeln.
Ein Photomultiplier besteht aus einer Photokathode und einem nachgeschalteten Sekundärelektronenvervielfacher.
Eine besondere Form der Photomultiplier sind sogenannte Mikrokanalplatten, wie sie auch in Bildverstärkern eingesetzt werden.
de.wikipedia.org /wiki/Photomultiplier   (383 words)

  
 Photomultiplier having gain stabilization means - Patent 5157250
A photomultiplier according to claims 1, 2 or 3, further comprising means for deactivating at least a third dynode of said plurality of dynodes when detecting said first voltage signal.
Photomultiplier tubes, or shortly photomultipliers, are common instruments in science and technology for detecting weak light levels.
An important quantity associated with photomultipliers is their amplification, or gain, defined as the ratio of anode current to cathode current and is typically 10.sup.5 -10.sup.9 depending on the number of dynodes, interdynode voltages and dynode materials.
www.freepatentsonline.com /5157250.html   (1818 words)

  
 [No title]
One of the important uses of a photomultiplier is to amplify the faint flashes of light produced in a scintillator by ionizing radiation.
The photomultiplier consists of a photocathode where electrons are emitted by the photoelectric effect, a number of dynodes where electron multiplication occurs and an anode for collecting the charge.
In a photomultiplier of N dynodes at each of which the secondary emission ratio is (the overall gain is (N where (is defined as the number of secondary electrons emitted per incident electron.
phy-server.phy.queensu.ca /~phys352c/pdf/06pmt.doc   (1154 words)

  
 Sensors Magazine Online - March 2000 - The Channel Photomultiplier and its Operation   (Site not responding. Last check: 2007-11-06)
Photomultipliers are high-gain, wide-bandwidth, optical detectors and, as with all such sensors, certain factors can limit their performance.
The response of the photomultiplier to a delta pulse of light is governed by the electron trajectories within the tube.
In the photomultiplier, the variation in output signal is related to the statistical fluctuation in the number of photoelectrons created (photoelectron noise).
www.sensorsmag.com /articles/0300/38/main.shtml   (1686 words)

  
 Photomultiplier   (Site not responding. Last check: 2007-11-06)
They are a type of vacuum tube in which photons produce electrons in a photocathode in consequence of the photoelectric effect and these electrons are subsequently amplified by multiplication on the surface of dynodes.
Their replacement by semiconductor device s has long been predicted but has never been achieved.
ADIT Designer and manufacturer of photomultiplier tubes for use in radiation detection and measurement devices.
www.serebella.com /encyclopedia/article-Photomultiplier.html   (262 words)

  
 Encyclopedia: Photomultiplier
In physics, the photon (from Greek φοτος, meaning light) is a quantum of excitation of the quantised electromagnetic field and is one of the elementary particles studied by quantum electrodynamics (QED) which is the oldest part of the Standard Model of particle physics.
Photomultipliers are constructed from a glass vacuum tube which houses a dynode and an anode.
Incident photons strike the photocathode material which is present as a thin deposit on the entry window of the device, with electrons being produced as a consequence of the photoelectric effect.
www.nationmaster.com /encyclopedia/Photomultiplier   (928 words)

  
 PHOTOMULTIPLIER   (Site not responding. Last check: 2007-11-06)
Photomultiplier sind spezielle Elektronenröhren um schwache Lichtsignale (bis hin zu einzelnen Photonen) zu verstärken.
In anderen Fällen geht es darum, die schwachen Lichtblitze, welche durch hochenergetische kosmische Strahlung in der Hochatmosphäre entstehen, nachzuweisen (Cerenkov- Leuchten) und auf diese Weise Informationen über kosmische Strahlungsquellen zu gewinnen.
Lawinenphotodioden, z.B. eingesetzt in Laserentfernungsmessern, können als das Halbleiteräquivalent zum Photomultiplier angesehen werden.
www.toonorama.com /encyclopedia/P/Photomultiplier   (187 words)

  
 PREVENTIVE MAINTENANCE SYSTEM FOR THE PHOTOMULTIPLIER DETECTOR BLOCKS OF PET SCANNERS   (Site not responding. Last check: 2007-11-06)
The quantitive comparisons used in the method of the present invention to provide an indication in the form of a display or printout advising the user that the photomultiplier block is stable, intermittently unstable, or drifting unstable, and also advising of the expected date of failure of a photomultiplier block in the PET scanner.
It includes a memory adapted for storing a record of a number of iterative adjustments that are necessary to calibrate the gain of a photomultiplier detector block i at a time t1 and a time T, where T t1 to, which is designated as Histo (i,j(t)).
This new method detects the instability of a photomultiplier and automatically indicates which of the hundreds of photomultipliers in the camera should be replaced before the photomultiplier fails, avoiding costly cancellations of experiments and testing of patients.
www.bnl.gov /techxfer/tech_briefs/11.html   (399 words)

  
 U.S.Geological Survey Open-File Report 03-029
The detector assembly is connected to an EGandG Ortec ScintiPack photomultiplier base (Model 296) using a standard JEDEC B14-38 socket with 14 pins.
The photomultiplier base is 2.2” in diameter by 6.75” in length.
photomultiplier base is the brown cylinder with an attached cable.
pubs.usgs.gov /of/2003/of03-029/HTML/Hardware.html   (270 words)

  
 Flying spot scanner burn corrector with dual photomultiplier sampling and mismatch signal suppression - Patent 5280166
Two photomultipliers (14,16) are arranged one on either side of a CRT (10) primary optical axis adjacent the imaging lens.
Adjacent the lens are two photomultipliers 14, 16 which do not interfere with the light input to the lens and are arranged as near as possible to the central optical axis.
The number of photomultipliers is not limited to two, for example, in high definition telecine it has been proposed to use two photomultipliers for each colour component of the video signal; six multipliers in all.
www.freepatentsonline.com /5280166.html   (2533 words)

  
 136   (Site not responding. Last check: 2007-11-06)
Photomultiplier tubes are an important class of radiation sensor used in nuclear physics research.
Present photomultiplier tubes are bulky, expensive, and not amenable to integration into large arrays despite recent advances in tube miniaturization.
The anticipated performance advantages of these photomultiplier tubes over conventional phototubes are that these photomultiplier tubes are vastly smaller, more rugged, have faster response, and can be readily integrated into arrays.
www.er.doe.gov /sbir/Awards_Abstracts/sbir/cycle15/phase1/136.htm   (268 words)

  
 Photomultiplier - Wikipedia, the free encyclopedia
Photomultipliers, or photomultiplier tubes (PMT) are extremely sensitive detectors of light in the ultraviolet, visible and near infrared.
These detectors multiply the signal produced from the incident light from which single photons are detectable.
Schematic of a photomultiplier tube coupled to a scintillator.
en.wikipedia.org /wiki/Photomultiplier   (370 words)

  
 Photomultiplier Tube Socket Assemblies - Products for Research Inc.
All photomultiplier tube socket assemblies are fully tested at Products for Research to insure mechanical and electrical integrity as well as very low electrical leakage (in the order of 1 PA) and full RFI shielding where applicable.
All photomultiplier tube socket assemblies for side looking tubes and tubes with rectangular apertures are constructed so that a rotational adjustment of ± 5° can be made while the tube is operating.
The ability to gate a photomultiplier is critical in applications such as LIDAR, where the light level to be measured is significantly lower than the excitation light level.
www.photocool.com /sockets.htm   (1073 words)

  
 A Cockcroft-Walton Base for the FEU84-3 Photomultiplier Tube
Several photomultiplier tube (PMT) base designs have been implemented which use the so-called Cockcroft-Walton voltage multiplier circuit to generate a graded series of voltages.[1-3] This type of circuit has the advantage of dissipating much less power than a resistive voltage divider.
A 3.9 cm square aluminum cap serves to affix the base and photomultiplier to a wall with 3.9 cm holes on 4 cm centers.
The stage-to-stage voltages are lowest at the cathode end of the photomultiplier leading to a low photoelectron collection efficiency, especially in the presence of magnetic fields.
dustbunny.physics.indiana.edu /~paul/cwbase/Welcome.html   (1848 words)

  
 Photomultiplier Enables Small-Scale Gamma Imaging - April, 2000   (Site not responding. Last check: 2007-11-06)
Using photomultiplier tubes from Hamamatsu Corp., researchers at the Thomas Jefferson National Accelerator Facility (Jefferson Lab) developed a compact gamma camera that is better suited to breast imaging applications.
Although several other research groups and start-up companies also are using Hamamatsu photomultiplier tubes, some are basing their gamma imagers on the PIN or avalanche photodiodes.
The R7600-00-C8, the Hamamatsu photomultiplier tube that the lab is using for most of its gamma imagers, offers good performance for the right price.
www.photonics.com /spectra/applications/XQ/ASP/aoaid.160/QX/read.htm   (554 words)

  
 McPherson, Inc. - Model 651 Dual Position Detector Housing   (Site not responding. Last check: 2007-11-06)
Glass windowed photomultiplier tube, selected for low dark current of the order of 10e-8 amperes, while maintaining a sensitivity of 2,000 amperes per lumen.
The fluorescent energy (at a wavelength of approximately 4,000 A) passes through the window of the photomultiplier envelope and strikes a photocathode surface.
With the proper power supplied to the photomultiplier tube, it converts the light energy striking its cathode to an electrical signal that can be amplified and read out on a strip chart recorder.
www.mcphersoninc.com /detectors/model651dualposition.htm   (372 words)

  
 photomultiplier doctor - faq 4   (Site not responding. Last check: 2007-11-06)
My problem is: I accidentally exposed the side window of a photomultiplier to ambient light during a routine maintenance.
Removing the bright light leaves the photomultiplier with an ion-damaged photocathode and filled with gas.
This is the worst case scenario but a photomultiplier will self-protect if the voltage divider is sufficiently resistive.
www.electron-tubes.co.uk /pmtdr/faq_004.html   (167 words)

  
 Payne's PMT Amplifier
The intensity and spectral characteristics of the fluorescence are measured by a Photomultiplier tube, and the substance is analyzed qualitatively and quantitatively.
However for many fluorescence spectrophotometer applications an inexpensive voltmeter is all that is required to convert the current of a Photomultiplier tube to a voltage signal proportional to the amount of light.
The Microscope Slide Setup incorporates 2 Photomultiplier tubes and the function of this PMT Amplifier module is to amplify and low-pass filter the input from the photomultiplier tubes, and interface these signals to a computer equipped for data acquisition.
www.luhs.org /depts/physio/personal_pages/pmt.htm   (1494 words)

  
 Newport Scientific - Oil-in-Compressed Gas Detector
Fluorescent emission will pass through the refraction blocking filter to the Photomultiplier Tube where it is transformed to a weak electrical signal and fed to the Photomultiplier Microphotometer for amplification and visual indication of intensity.
The Photomultiplier Microphotometer is provided with a 115v, 60Hz circuit that can be made to trigger a visual or audible alarm, a motor controller, an electrically-actuated shut-off valve, or any combination of these devices, thus warning of contamination in the gas stream.
Photomultiplier Tube (Type 1P21) with integral cable for connection to Photomultiplier Microphotometer; One 62155062500 mercury vapor lamp and one P1502040700 stabilizer ballast transformer that powers the mercury lamp.
www.newport-scientific.com /OilInCompressedGasDetector.htm   (861 words)

  
 [No title]   (Site not responding. Last check: 2007-11-06)
The photomultiplier, as its name suggests, multiplies the small flash of light into a large electrical signal that can be measured.
The scintillator and the photomultiplier are housed in a dark box so that the only light detected is caused by cosmic rays.
The sides of the water tank are lined with reflective material and some of this light is reflected onto a photomultiplier which produces an electronic signal.
ast.leeds.ac.uk /haverah/detector.shtml   (314 words)

  
 Info about Super-Kamiokande
A photon enters the photomultiplier through the glass surface and hits the photo-cathode, which is placed on the inner surface of the glass.
The signal created by the swarm of electrons enters a cable and travels from the photomultiplier to the electronics hut located at the top of the tank.
The signal from all photomultipliers is converted to digital form, analyzed and passed to computers which further analyze it.
www.ps.uci.edu /~superk/sk-info.html   (2349 words)

  
 Queen's Sudbury Neutrino Observatory Group: Analysis   (Site not responding. Last check: 2007-11-06)
SNO detects neutrinos because neutrino interactions in water produce small flashes of light which are detected by the array of photomultiplier tubes around SNO's volume of heavy water.
This is a photo taken with a fish-eye lens from the very bottom of the SNO detector just before the last photomultiplier tubes were installed.
Each photomultiplier can detect a single photon of light and determine its arrival time with an uncertainty 1.5 nanoseconds (billionths of a second).
sno.phy.queensu.ca /sno/queens/analysis.html   (196 words)

  
 Photomultiplier Tubes (PMTs), Hamamatsu
Photomultiplier tubes (PMT) have high bandwidth and noise-free gain on the order of a million.
Photomultipliers can be used to detect photons from 115nm to 1700nm.
A typical Photomultiplier consists of a photoemissive cathode (photocathode) followed by an electron multiplier and an electron collector (anode).
pmt.hamamatsu.com /en/products/electron-tube-division/detectors/photomultiplier-tubes-pmts.php   (163 words)

  
 Photomultiplier Tube (PMT) high voltage power supply
Specifically designed high voltage power supply units are the ideal size, within the ideal noise and stability requirements for photomultiplier tube.
Matsusada's photomultiplier power supplies kill ripple noise and spike noise which are critical for detectors.
The size of our photomultiplier tube high voltage power supply units is, even with low ripple noise, quite compact to save your space.
www.matsusada.com /high-voltage/photomultiplier-tube.html   (250 words)

  
 The Photomultiplier   (Site not responding. Last check: 2007-11-06)
However, th human eye is too slow and unreliable for an efficient use of this type, so the scintillation counter was abandoned for many years.
It was reintroduced in 1944 with a photomultiplier replacing the eye.
These photons are transmitted through a shaped light pipe to the photocathode of a photomultiplier.
www.physics.sfsu.edu /~hbarden/PH490/EXP1/photo.html   (198 words)

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