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When we choose X and γ-ray detection equipment, we always hear the names of many types of detectors, such as GM counting tubes, proportional counting tubes, plastic scintillator, NaI (Tl) scintillator, CsI (Tl) scintillator , CLYC scintillator, CZT detector, high-purity germanium detector, silicon semiconductor detector, etc. So, what are the specific differences between these detections? Is this detector suitable for my work scenario? And can it meet my performance needs?
There are many types of detectors, which can be mainly divided into gas detectors, scintillator detectors and semiconductor detectors. This article first introduces to you plastic scintillator and NaI(Tl) scintillator, two common types of scintillator detectors that have considerable overlapping ranges of application, so that everyone can have an idea when facing a choice. , select the most suitable scintillator material.
Plastic scintillator is a type of organic scintillator. Organic scintillator crystals mainly include anthracene crystals, liquid scintillator, and plastic scintillator. Plastic scintillator is a solid body of organic scintillator substances in plastic, generally composed of matrix scintillator substances and wave-shifting agents. The matrix material is mostly polystyrene and other scintillation substances. The function of the wave shifting agent is to effectively and quickly transmit and extend the scintillation light. Plastic scintillator is not a crystal, but an organic scintillator, which can be used for the detection of a variety of radioactive rays.
Plastic scintillator has the following characteristics:
Plastic scintillator can be easily prepared into large-volume transparent bodies and easily processed into various shapes. Plastic scintillator can also be made into optical fibers to facilitate coupling with optoelectronic devices under various geometric conditions.
The plastic scintillator does not deliquesce, which makes it unnecessary to adopt strict packaging measures. Even if the detector body is exposed in the air, it will not affect the detector itself.
The plastic scintillator material has good radiation resistance. Under the irradiation of high dose rate X and γ rays, the detector is not prone to irreversible damage.
The scintillation decay time of plastic scintillator is short, and equipment equipped with this type of detector can even achieve a pulse ray response speed of less than 10ms.
The light output yield of plastic scintillator is higher, but not as good as NaI(Tl) scintillator.
NaI(Tl) scintillator is a type of inorganic scintillator. Inorganic scintillators include NaI(Tl) scintillator, CLYC scintillator, CsI(Tl) scintillator, etc., as well as other inorganic crystals (such as cadmium tungstate, germanium bismuth acid, etc.) and even vitreous. The most widely used one is the NaI(Tl) scintillator detector (NaI(Tl) crystal). Since its introduction in 1948, it is still the most important scintillator for detecting X-rays, gamma rays and alpha rays. NaI(Tl) scintillator has the following characteristics:
The luminous efficiency of NaI(Tl) scintillator is the highest among all scintillation crystals coupled to photomultiplier tubes, with a light yield of 38,000 (number of photons/MeVγ). The luminous efficiency of other crystals is often calculated relative to NaI (Tl) expressed as a percentage.
NaI(Tl) scintillator has a high resolution. In addition to being used for measuring X and γ dose rates, it can also be installed in nuclide identification equipment to analyze energy spectra and identify nuclide types.
NaI(Tl) scintillator has higher luminous intensity at high temperatures, which makes it more adaptable in situations with higher ambient temperatures, such as oil wells or space detection.
NaI(Tl) scintillator is susceptible to radiation damage. If exposed to high-intensity irradiation for a long time, its scintillation performance will be reduced. Generally, radiation damage will be observed when the radiation intensity dose is higher than 1Gy.
The scintillation decay time of NaI(Tl) scintillator is shorter, but not as good as that of plastic scintillator.
NaI(Tl) scintillator is easy to deliquesce, so it requires a sealed enclosure.
In many high-tech equipment such as high-energy physics and space research, medical imaging, and rapidly developing industrial detection and safety inspections, scintillator detectors are ubiquitous. Their biggest advantages are that they are easy to use, not restricted by space, and have high detection efficiency. Due to its large size and sensitivity, it is extremely adaptable to the environment, making it a widely used radiation detector. Among them, plastic scintillator and NaI(Tl) scintillator are typical representatives of scintillator detectors.
