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NaI(Tl) scintillation crystals are used in most standard applications for
detection of g-radiation
because of their unequalled high light output and the excellent match of the emission
spectrum to the sensitivity of photomultiplier tubes, resulting in a good energy
resolution. |
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CsI(Tl) has the advantage that it is non-hygroscopic, does not cleave and can be
read out using silicon photodiodes instead of photomultiplier tubes. These so-called Scintillator
Photodiode Detectors are compact, very stable, do not require any high voltage, are
rugged, and can be operated in high magnetic fields. These detectors are frequently used
in arrays or matrices in particle physics research. |
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CsI(Na) is a non-hygroscopic, high light output scintillator mainly used for
applications where mechanical stability and good energy resolution are required. Below 120
oC it is an alternative to NaI(Tl). |
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BGO has the extreme high density of 7.13 g /cm3 and has a high Z
value which makes these crystals very suited for the detection of natural radioactivity
(U, Th, K), for high energy physics applications (high photofraction) or in compact
Compton suppression spectrometers. |
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YAP:Ce is a high density (5.5 g/cm3) oxide crystal with a decay time
about 10 times shorter than NaI(Tl). It is used in detectors for high count rate (up to
several MHz) X-ray spectrometry. The non-hygroscopic nature of this material allows the
use of thin mylar entrance windows and guarantees a long lifetime of the detector. |
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CaF2(Eu), Europium doped calcium fluoride is a low density scintillation crystal
with a high light output. Thanks to its low Z value it is well suited for the detection of
electrons (beta particles) with a high efficiency (low backscatter fraction). CaF2
(Eu) is a crystal that is also used in phoswich scintillation detectors in
combination with NaI(Tl). |
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Organic
(plastic) scintillators consist of a transparent host
material (a plastic) doped with a scintillating organic molecule (e.g. POPOP : p-bis
[2-(5-phenyloxazolyl)] benzene). Radiation is absorbed by the host material, mostly via
Compton effect because of the low density and Z- value of organic materials. Therefore,
plastic scintillators are mostly used for the detection of b- and other particles. Furthermore plastic
scintillators are mainly used when large detector volumes are required e.g. in security or
health physics applications. The cost of large plastic scintillation detectors (per
volume) is much lower than that of equivalent size NaI(Tl) detectors; plastic
scintillators can be manufactured in meter long slabs. |
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