A scintillator is a material that scintillates, that is, exhibits luminescence[1] when ionizing radiation (electrons, positrons or other heavier particles or ions) passes through it. This occurs because the material absorbs part of the energy of the incident particle and re-emits it in the form of a short flash of light, typically in the visible light range. If this reemission is rapid (less than about 10 s), the phenomenon is known as fluorescence. Otherwise, if the excitation is metastable and lasts from microseconds to hours, we refer to the phenomenon as phosphorescence.
History
The first device to use a scintillator was built in 1903 by Sir William Crookes and used a ZnS screen to observe bombardment by alpha particles.[2][3] The scintillations produced by the screen were visible to the naked eye and did not require microscopes or a dark room; the device was known as a spinthariscope. The technique led to a number of important discoveries, but was obviously tedious. Scintillators attracted more attention in 1944, when Curran and Baker replaced naked-eye measurement with the newly developed PMT. This was the birth of the modern scintillator detector.[2].
Scintillation detector
We speak of a scintillation detector or scintillator detector when we join a scintillator material to a light sensor, such as a photomultiplier (photomultiplier tube: photomultiplier tube) or a photodiode. The photomultiplier absorbs the light emitted by the scintillator and re-emits it as electrons through the photoelectric effect, and then causes the electrons to multiply in a cascade of dynodes at a higher electrical potential and end up producing an electric current. Photodiodes generate current in a piece of silicon.
This is based on a property called visible light emission, better known as luminescence. This property occurs when these substances are exposed to ionizing radiation. The molecular excitation produced gives rise to a rapid de-excitation known as fluorescence or scintillation.
Each visible light emission or flash corresponding to a single photon can be detected and, if a transducer element is available, transformed into an electrical signal.
Luminescence detectors
Introduction
A scintillator is a material that scintillates, that is, exhibits luminescence[1] when ionizing radiation (electrons, positrons or other heavier particles or ions) passes through it. This occurs because the material absorbs part of the energy of the incident particle and re-emits it in the form of a short flash of light, typically in the visible light range. If this reemission is rapid (less than about 10 s), the phenomenon is known as fluorescence. Otherwise, if the excitation is metastable and lasts from microseconds to hours, we refer to the phenomenon as phosphorescence.
History
The first device to use a scintillator was built in 1903 by Sir William Crookes and used a ZnS screen to observe bombardment by alpha particles.[2][3] The scintillations produced by the screen were visible to the naked eye and did not require microscopes or a dark room; the device was known as a spinthariscope. The technique led to a number of important discoveries, but was obviously tedious. Scintillators attracted more attention in 1944, when Curran and Baker replaced naked-eye measurement with the newly developed PMT. This was the birth of the modern scintillator detector.[2].
Scintillation detector
We speak of a scintillation detector or scintillator detector when we join a scintillator material to a light sensor, such as a photomultiplier (photomultiplier tube: photomultiplier tube) or a photodiode. The photomultiplier absorbs the light emitted by the scintillator and re-emits it as electrons through the photoelectric effect, and then causes the electrons to multiply in a cascade of dynodes at a higher electrical potential and end up producing an electric current. Photodiodes generate current in a piece of silicon.
This is based on a property called visible light emission, better known as luminescence. This property occurs when these substances are exposed to ionizing radiation. The molecular excitation produced gives rise to a rapid de-excitation known as fluorescence or scintillation.
When the photon or charged particle hits a material medium, the phenomenon of luminescence is created. A part of the energy is invested in ionizations and excitations. These are followed by emissions of electromagnetic waves. Their production takes place in the visible and ultraviolet regions. [1].
They can be organic or inorganic. The difference lies depending on the radiation detected. If they are photons, the scintillator will be made of a material with the following characteristics: good luminous transparency, a high atomic number (Z) and a large detection volume. The most appropriate for beta particles are organic ones, since having a low atomic number favors the penetration of the particle into the detector. No special conditions are necessary for alphas.
LIQUID phase scintillation: used in beta particle measurement applications and when extreme sensitivity is required. Compared to solid scintillators, when generating the light intensity that comes from a detection, they have a very fast response, which allows them to carry out measurements of high activities.
It is the device that is responsible for transforming the luminous intensity of a flicker into a proportional electrical signal. An optical contact connects it to the scintillator. It consists of a highly sensitive photoelectric cell. The electrical impulse is generated thanks to the collision of electrons released from a photocatade that, through the action of light, releases electrodes called dynodes. Everything is closed inside a vacuum blister.
The electrical impulse is proportional to the incident radiation when it gives up all its energy to the scintillator. However, not all photons remove electrons from the dynodes, but depend on a probability that is based on the sensitivity of the photocatade to each specific wavelength.
Uses
Scintillator detectors are widely used in particle physics, astroparticle physics, oil exploration, spectrometry, container and baggage scanning, space physics and medical physics (PET [positron emission tomography], imaging therapy, etc.).
Find more "Luminescence detectors" in the following countries:
[1] ↑ Leo, W. R. (1994): Techniques for nuclear and particle physics experiments, segunda edición, Springer-Verlag. (en inglés).
[2] ↑ a b Leo , 1994, p. 157.
[3] ↑ Dyer, 2001, p. 920.
Each visible light emission or flash corresponding to a single photon can be detected and, if a transducer element is available, transformed into an electrical signal.
When the photon or charged particle hits a material medium, the phenomenon of luminescence is created. A part of the energy is invested in ionizations and excitations. These are followed by emissions of electromagnetic waves. Their production takes place in the visible and ultraviolet regions. [1].
They can be organic or inorganic. The difference lies depending on the radiation detected. If they are photons, the scintillator will be made of a material with the following characteristics: good luminous transparency, a high atomic number (Z) and a large detection volume. The most appropriate for beta particles are organic ones, since having a low atomic number favors the penetration of the particle into the detector. No special conditions are necessary for alphas.
LIQUID phase scintillation: used in beta particle measurement applications and when extreme sensitivity is required. Compared to solid scintillators, when generating the light intensity that comes from a detection, they have a very fast response, which allows them to carry out measurements of high activities.
It is the device that is responsible for transforming the luminous intensity of a flicker into a proportional electrical signal. An optical contact connects it to the scintillator. It consists of a highly sensitive photoelectric cell. The electrical impulse is generated thanks to the collision of electrons released from a photocatade that, through the action of light, releases electrodes called dynodes. Everything is closed inside a vacuum blister.
The electrical impulse is proportional to the incident radiation when it gives up all its energy to the scintillator. However, not all photons remove electrons from the dynodes, but depend on a probability that is based on the sensitivity of the photocatade to each specific wavelength.
Uses
Scintillator detectors are widely used in particle physics, astroparticle physics, oil exploration, spectrometry, container and baggage scanning, space physics and medical physics (PET [positron emission tomography], imaging therapy, etc.).
Find more "Luminescence detectors" in the following countries: