Principle of nuclear radiation detector

Nuclear radiation detector is an instrument used to detect and measure the level of nuclear radiation in the environment. Its working principle is based on the interaction between nuclear radiation and matter. Nuclear radiation detectors usually use detectors to detect nuclear radiation in the environment. The most common detectors are scintillator detectors, semiconductor detectors and ionization chamber detectors.

1, scintillator detector

Nuclear radiation is detected by scintillation effect. When nuclear radiation interacts with scintillator, atoms or molecules in scintillator will absorb energy and release it again in a short time. This process of releasing energy is accompanied by the emission of visible light, which can be measured by photomultiplier tube or photodiode.

2. Semiconductor detectors

Using the response of electrons and holes in semiconductor materials to nuclear radiation. When nuclear radiation enters the semiconductor material, it will excite electrons and holes in the semiconductor, leading to the accumulation of charges. These charges can be measured by circuits.

3. Ionization chamber detector

Nuclear radiation is detected by ionization effect in gas. When nuclear radiation passes through the gas in the ionization chamber, it will produce ionization, that is, electrons and positive ions. The intensity of nuclear radiation can be determined by measuring the ionization current or voltage in the ionization chamber.

The main types of nuclear radiation:

1, α particle: α particle is a heavy ion composed of two protons and two neutrons with a charge of +2. Alpha particles are relatively large and have strong ionization energy, but their penetration ability is relatively weak. Travel in the air can only travel a few centimeters.

2. Beta particles: Beta particles can be electrons (beta particles) or positrons (beta+particles). Beta particles are smaller than alpha particles and have strong penetration ability, and can travel through the distance of several meters to dozens of meters in matter.

3.γ-ray: γ-ray is high-energy electromagnetic radiation, which has no charge and mass and strong penetration ability. Gamma rays can penetrate most substances, even a few centimeters to dozens of centimeters thick.