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Scintillators
A scintillator is a material that exhibits scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light). Sometimes, the excited state is metastable, so the relaxation back down from the excited state to lower states is delayed (necessitating anywhere from a few nanoseconds to hours depending on the material). The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon. Principle of operation A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintillator and re-emit it in the form of ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Plastic Scintillator
A scintillator is a material that exhibits scintillation (physics), scintillation, the property of luminescence, when excited by ionizing radiation. Luminescent materials, when struck by an incoming particle, absorb its energy and scintillate (i.e. re-emit the absorbed energy in the form of light). Sometimes, the excited state is Metastability, metastable, so the relaxation back down from the excited state to lower states is delayed (necessitating anywhere from a few nanoseconds to hours depending on the material). The process then corresponds to one of two phenomena: delayed fluorescence or phosphorescence. The correspondence depends on the type of transition and hence the wavelength of the emitted optical photon. Principle of operation A scintillation detector or scintillation counter is obtained when a scintillator is coupled to an electronic light sensor such as a photomultiplier tube (PMT), photodiode, or silicon photomultiplier. PMTs absorb the light emitted by the scintill ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillation (physics)
Scintillation is the physical process where a material, called scintillator, emits UV or visible light under excitation from high energy photons (X-rays or γ-rays) or energetic particles,(such as electrons, alpha particles, neutrons or ions). See scintillator and scintillation counter for practical applications. Overview The process of scintillation is one of luminescence whereby light of a characteristic spectrum is emitted following the absorption of radiation. The scintillation process can be summarized in three main stages (A) conversion, (B) transport and energy transfer to the luminescence center, and (C) luminescence. The emitted radiation is usually less energetic than the absorbed radiation, hence generally scintillation is a down-conversion process. Conversion processes The first stage of scintillation, conversion, is the process where the energy from the incident radiation is absorbed by the scintillator and highly energetic electrons and holes are created in th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Scintillation Counter
A scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillating material, and detecting the resultant light pulses. It consists of a scintillator which generates photons in response to incident radiation, a sensitive photodetector (usually a photomultiplier tube (PMT), a charge-coupled device (CCD) camera, or a photodiode), which converts the light to an electrical signal and electronics to process this signal. Scintillation counters are widely used in radiation protection, assay of radioactive materials and physics research because they can be made inexpensively yet with good quantum efficiency, and can measure both the intensity and the energy of incident radiation. History The first electronic scintillation counter was invented in 1944 by Sir Samuel Curran whilst he was working on the Manhattan Project at the University of California at Berkeley. There was a requirement to measur ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
US Navy 070208-N-9132D-002 Electronics Technician 2nd Class Shea Thompson Tests An Alpha Particle Dection Probe
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territories, nine Minor Outlying Islands, and 326 Indian reservations. The United States is also in free association with three Pacific Island sovereign states: the Federated States of Micronesia, the Marshall Islands, and the Republic of Palau. It is the world's third-largest country by both land and total area. It shares land borders with Canada to its north and with Mexico to its south and has maritime borders with the Bahamas, Cuba, Russia, and other nations. With a population of over 333 million, it is the most populous country in the Americas and the third most populous in the world. The national capital of the United States is Washington, D.C. and its most populous city and principal financial center is New York City. Paleo-Ameri ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Zinc Sulfide
Zinc sulfide (or zinc sulphide) is an inorganic compound with the chemical formula of ZnS. This is the main form of zinc found in nature, where it mainly occurs as the mineral sphalerite. Although this mineral is usually black because of various impurities, the pure material is white, and it is widely used as a pigment. In its dense synthetic form, zinc sulfide can be transparent, and it is used as a window for visible optics and infrared optics. Structure ZnS exists in two main crystalline forms. This dualism is an example of polymorphism. In each form, the coordination geometry at Zn and S is tetrahedral. The more stable cubic form is known also as zinc blende or sphalerite. The hexagonal form is known as the mineral wurtzite, although it also can be produced synthetically.. The transition from the sphalerite form to the wurtzite form occurs at around 1020 °C. A tetragonal form is also known as the very rare mineral called polhemusite, with the formula . Applicatio ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Spinthariscope
A spinthariscope () is a device for observing individual nuclear disintegrations caused by the interaction of ionizing radiation with a phosphor (see radioluminescence) or scintillator. Invention The spinthariscope was invented by William Crookes in 1903. While observing the apparently uniform fluorescence on a zinc sulfide screen created by the radioactive emissions (mostly alpha radiation) of a sample of radium bromide, he spilled some of the sample, and, owing to its extreme rarity and cost, he was eager to find and recover it. Upon inspecting the zinc sulfide screen under a microscope, he noticed separate flashes of light created by individual alpha particle collisions with the screen. Crookes took his discovery a step further and invented a device specifically intended to view these scintillations. It consisted of a small screen coated with zinc sulfide affixed to the end of a tube, with a tiny amount of radium salt suspended a short distance from the screen and a lens on th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Samuel Curran
Sir Samuel Crowe Curran (23 May 1912 – 15 February 1998), Royal Society, FRS, FRSE, was a physicist and the first Principal and Vice-Chancellor of the University of Strathclyde – the first of the new technical universities in Britain. He is the inventor of the scintillation counter, the proportional counter, and the proximity fuze. To date, Curran remains the longest serving principal and vice chancellor of the University of Strathclyde, holding the post for 16 years, not counting his previous five years as principal of the Royal College of Science and Technology. Life Samuel Curran was born on 23 May 1912 at Ballymena in Northern Ireland, the son of John Hamilton Curran (from Kinghorn in Fife), and his wife, Sarah Carson Crowe (some sources state Sarah Owen Crowe). The family moved to Scotland soon after for his father to work as foreman of a steelworks near Wishaw. His brother Robert Curran (physician), Robert Curran, later a famous pathologist, was born soon after. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Photomultiplier
A photomultiplier is a device that converts incident photons into an electrical signal. Kinds of photomultiplier include: * Photomultiplier tube, a vacuum tube converting incident photons into an electric signal. Photomultiplier tubes (PMTs for short) are members of the class of vacuum tubes, and more specifically vacuum phototubes, which are extremely sensitive detectors of light in the ultraviolet, visible, and near-infrared ranges of the electromagnetic spectrum. ** Magnetic photomultiplier, developed by the Soviets in the 1930s. ** Electrostatic photomultiplier, a kind of photomultiplier tube demonstrated by Jan Rajchman of RCA Laboratories in Princeton, NJ in the late 1930s which became the standard for all future commercial photomultipliers. The first mass-produced photomultiplier, the Type 931, was of this design and is still commercially produced today. * Silicon photomultiplier, a solid-state device converting incident photons into an electric signal. Silicon photomultiplie ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Particle Detector
In experimental and applied particle physics, nuclear physics, and nuclear engineering, a particle detector, also known as a radiation detector, is a device used to detect, track, and/or identify ionizing particles, such as those produced by nuclear decay, cosmic radiation, or reactions in a particle accelerator. Detectors can measure the particle energy and other attributes such as momentum, spin, charge, particle type, in addition to merely registering the presence of the particle. Examples and types Many of the detectors invented and used so far are ionization detectors (of which gaseous ionization detectors and semiconductor detectors are most typical) and scintillation detectors; but other, completely different principles have also been applied, like Čerenkov light and transition radiation. Historical examples *Bubble chamber * Wilson cloud chamber (diffusion chamber) * Photographic plate ;Detectors for radiation protection The following types of particle detector ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
William Crookes
Sir William Crookes (; 17 June 1832 – 4 April 1919) was a British chemist and physicist who attended the Royal College of Chemistry, now part of Imperial College London, and worked on spectroscopy. He was a pioneer of vacuum tubes, inventing the Crookes tube which was made in 1875. This was a foundational discovery that eventually changed the whole of chemistry and physics. He is credited with discovering the element thallium, announced in 1861, with the help of spectroscopy. He was also the first to describe the spectrum of terrestrial helium, in 1865. Crookes was the inventor of the Crookes radiometer but did not discern the true explanation of the phenomenon he detected. Crookes also invented a 100% ultraviolet blocking sunglass lens. For a time, he was interested in spiritualism and became president of the Society for Psychical Research. Biography Crookes' life was one of unbroken scientific activity that extended over sixty-seven years. He was considered remarkable for ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Survey Meter
Survey meters in radiation protection are hand-held ionising radiation measurement instruments used to check such as personnel, equipment and the environment for radioactive contamination and ambient radiation. The hand-held survey meter is probably the most familiar radiation measuring device owing to its wide and visible use. Types The most commonly used hand-held survey meters are the scintillation counter, which is used in the measurement of alpha, beta and neutron particles; the Geiger counter, widely used for the measurement of alpha, beta and gamma levels; and the ion chamber, which is used for beta, gamma and X-ray measurements. Functional design The instruments are designed to be hand-held, are battery powered and of low mass to allow easy manipulation. Other features include an easily readable display, in counts or radiation dose, and an audible indication of the count rate. This is usually the “click” associated with the Geiger type instrument, and can also be an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
