Many of the sources we encounter in daily life have very low radiation doses, so there is no need to worry. However, ionizing radiation can also be dangerous because these free electrons interact with molecules within the cells and tissues of the human body. Adding extra electrons can break the chemical bonds that hold molecules together. This is why radioactive materials from nuclear weapons and power plant meltdowns can increase the risk of cancer.
There are four types of ionizing radiation: alpha, beta, gamma, and neutron radiation. Here’s what’s going on with each type and how to detect them.
alpha particles
In 1896, no one really knew anything about radiation. They didn’t know if it was a particle or an electromagnetic wave like light. So they decided to use the term “ray” in its general sense, like a ray of light. This is how we get holdover terms like alpha and gamma rays.
However, spoiler alert, alpha rays are not waves. They are actually charged particles. Alpha particles are made up of two protons and two neutrons. This means that alpha particles are helium atoms without electrons. (Yes, they should have called them “helium particles,” but no one knew what was going on.)
How do we know it’s an alpha particle and not some other type? The answer is that alpha particles are easily blocked by objects as thin as paper. Therefore, if you have a source that produces alpha particles, you can shield your detector, such as photographic film, with a very small amount of material.
The reason alpha particles are so easily blocked is because they are so heavy that they are often emitted from radiation sources at relatively slow speeds. Also, because it has a charge equal to two protons, there is a large electrostatic force between the alpha particle and the proton nucleus of the shielding paper. (This is called the 2nd charge)ewhere e is the fundamental charge of an electron or proton. ) It doesn’t take many of these atoms in the paper to effectively stop the alpha particle.
Do you know what else can stop alpha particles? Human skin. Therefore, alpha radiation is considered the least harmful of all types of radiation.
beta particles
In 1899, Ernest Rutherford classified radiation into three types: alpha, beta, and gamma. Alpha particles were easily stopped, but beta and gamma particles have much lower masses, so they can pass through some degree of metal shielding and penetrate further into matter. In fact, a beta particle is an electron, a fundamental particle with a negative charge. Alpha particles have more than 7,000 times the mass of beta particles. This means that beta particles of very low mass can be emitted at very high velocities and can penetrate objects, including the human body.
gamma ray
gamma ray teeth It’s actually a ray, not a particle. These are the third class of radiation and, like visible light, are a type of electromagnetic radiation.
However, while the wavelength of light that can be seen by the eye is between 400 and 700 nanometers, the wavelength of gamma rays is even shorter. A typical gamma ray wavelength is 100 picometers. (Note: 1 picometer = 10-12 meter, 1 nanometer = 10-9 This means that the wavelength of gamma rays can be about 1,000 times smaller than that of visible light. Because of this short wavelength and very high frequency, gamma rays can interact with matter at very high energy levels. It also typically requires large amounts of lead to block this radiation, as it can penetrate quite deeply into most materials.