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An important application of caesium iodide crystals, which are scintillators, is electromagnetic calorimetry in experimental particle physics.Pure CsI is a fast and dense scintillating material with relatively low light yield that increases significantly with cooling, [11] and a fairly small Molière radius is 3.5 cm.
The scintillation process is the same as described for organic crystals (above); what differs is the mechanism of energy absorption: energy is first absorbed by the solvent, then passed onto the scintillation solute (the details of the transfer are not clearly understood). [36]
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.
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).
This is another mechanism of phosphor degradation. The scintillation process in inorganic materials is due to the electronic band structure found in the crystals . An incoming particle can excite an electron from the valence band to either the conduction band or the exciton band (located just below the conduction band and separated from the ...
Another application of thallium doping is the sodium iodide and cesium iodide crystals in gamma radiation detection devices. In these, the sodium iodide crystals are doped with a small amount of thallium to improve their efficiency as scintillation generators. [53] Some of the electrodes in dissolved oxygen analyzers contain thallium. [9]
Figure 1: Sodium iodide gamma spectrum of caesium-137 (137 Cs) An example of a NaI spectrum is the gamma spectrum of the caesium isotope 137 Cs —see Figure 1. 137 Cs emits a single gamma line of 662 keV. The 662 keV line shown is actually produced by 137m Ba, the decay product of 137 Cs, which is in secular equilibrium with 137 Cs.
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.