Use of Scintillator for Gamma Rays

[m-i-t-o]

Hi all, i want to ask use of scintillator. Actually what i studied that to convert highly energetic gamma rays, to visible photon we use scintillator before p.m. tube, so that photoelectric effect can occur and we get photo-electrons.
But when gamma rays interact with matter in three different ways, i.e. photo-electric effect, compton effect, pair production. Since we are getting photoelectric effect then why we need to convert it to visible photon and allow directly to incident on p.m. tube?
THANKS

 

[malawi_glenn]

We want to measure the photons electronically, and this you do by a PM tube.

But you can't mount the PM tubes everywhere on the scinitillating material, so you build *light gates* which are transparent and works as optical fibres, to lead the light into optical fibres to the PM tubes where the photons are recorded electronically.

And why you need visible light? -well do you know of any optical fibres for microwavelengths or X-rays, you tell me :-)

So you use scinitillating material which emits in the visible part of spectra, where optical fibres etc exists.

 

[sir-pinski]

The use of scintillator for gamma rays is an important technique in the field of radiation detection. Scintillators are materials that emit light when they are exposed to radiation. This light can then be detected by a photomultiplier tube (p.m. tube) to measure the intensity and energy of the incident gamma rays.

The main reason for using a scintillator is to convert the highly energetic gamma rays into visible photons. This is because the photomultiplier tube can only detect visible light, not gamma rays. By using a scintillator, the gamma rays are converted into visible light, which can then be detected by the p.m. tube.

It is true that gamma rays can interact with matter in three different ways, as you mentioned - the photoelectric effect, Compton effect, and pair production. However, the photoelectric effect is the most dominant interaction with low energy gamma rays. This means that most of the gamma rays will be converted into visible light through the photoelectric effect, making it the most efficient way to detect them.

Additionally, using a scintillator also helps to improve the efficiency and accuracy of the detection process. By converting the gamma rays into visible light, we can better control and measure the intensity and energy of the radiation. This is important in many applications, such as medical imaging and radiation therapy.

In summary, the use of a scintillator for gamma rays is essential for converting the high-energy radiation into visible light, which can then be detected by a photomultiplier tube. This allows for more accurate and efficient detection of gamma rays, making it a crucial tool in the field of radiation detection.