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CsI(Tl) is only slightly hygroscopic and does not usually require an airtight enclosure. GaAs or gallium arsenide (suitably doped with silicon and boron impurities) is a cryogenic n-type semiconductor scintillator with a low cryogenic bandgap (1.52 eV) and high light output (100 photons/keV) in the infra-red (930 nm). The absence of thermally ...
In condensed matter physics, scintillation (/ ˈ s ɪ n t ɪ l eɪ ʃ ən / SIN-til-ay-shun) is the physical process where a material, called a scintillator, emits ultraviolet or visible light under excitation from high energy photons (X-rays or gamma rays) or energetic particles (such as electrons, alpha particles, neutrons, or ions).
The scintillator consists of a transparent crystal, usually a phosphor, plastic (usually containing anthracene) or organic liquid (see liquid scintillation counting) that fluoresces when struck by ionizing radiation. Cesium iodide (CsI) in crystalline form is used as the scintillator for the detection of protons and alpha particles.
The PMT gives a reliable and efficient method of detection since it can multiply the initial signal of a single scintillation photon hitting the PMT face millions of times into a measurable electrical pulse. Even so, scintillator detector design has room for improvement as do other options for neutron detection besides scintillation.
Liquid scintillation counter. Samples are dissolved or suspended in a "cocktail" containing a solvent (historically aromatic organics such as xylene or toluene, but more recently less hazardous solvents are used), typically some form of a surfactant, and "fluors" or scintillators which produce the light measured by the detector.
Indirect detectors contain a layer of scintillator material, typically either gadolinium oxysulfide or cesium iodide, which converts the x-rays into light.Directly behind the scintillator layer is an amorphous silicon detector array manufactured using a process very similar to that used to make LCD televisions and computer monitors.
Some signals do not have a sharp maximum, but short rise times . Typical input signals for CFDs are pulses from plastic scintillation counters, such as those used for lifetime measurement in positron annihilation experiments. The scintillator pulses have identical rise times that are much longer than the desired temporal resolution.
In phosphors and scintillators, the activator is the element added as dopant to the crystal of the material to create desired type of nonhomogeneities.. In luminescence, only a small fraction of atoms, called emission centers or luminescence centers, emit light.