X-rays, like visible light, are a type of electromagnetic radiation. X rays have a higher energy than light and can penetrate through most objects, including the human body. Medical x rays are used to provide images of internal organs and tissues. If x-rays passing through the body also pass through an x-ray detector on the patient’s side, an image representing the “shadows” made by the items inside the body is created. X rays possess very high energy ranging from 100 eV to 100 keV. They lie in end of electromagnetic spectrum, before gamma rays portion. They are produced by the inner electronic transitions in an atom. Here we will discuss, what are x rays, how are they produced and what is their use.
Production of X-rays
X-rays are produced when high speed electrons collide on a metal surface. As a result, they are absorbed by the metal plate and release energy in form of x-rays (also known as cathode rays). They are used in medical applications like anatomy of body parts. When beam of x rays comes in contact with body tissues then it produces an image on metal film. It happens because soft tissues (skin or organs) can’t absorb them however dense materials inside body like bones can absorb them, thus giving inside picture of body. In x-ray image of any body part, black areas represent the body parts from where x-rays have passed while white area shows denser tissues.
Properties of x rays
- In electromagnetic spectrum, they have shorter wavelength.
- High voltage is required for their production.
- They don’t have electric charge.
- They move in straight line.
- They can travel in vacuum.
- They travel with the speed of light.
- They have ability to penetrate optically through opaque
- They lie in maximum energy portion of spectrum.
- They have no charge.
- X rays are massless.
Types of X-rays
X rays are classified into two types according to their wavelength.
Soft x-rays and hard x-rays
The x-rays with short wavelength about 10 nm are known as soft x rays and those with greater wavelength about 100 pm are called hard x rays.
On the basis of production, they are classified into two categories.
Characteristic x-rays and Bremsstrahlung x-rays
Characteristic x rays are produced when high energy particles like photons, electrons or ions are bombarded on an element. As a result of this bombardment, the electron from inner energy level gets ejected producing a hole. To cover this vacancy, an electron from higher energy level falls to lower energy level vacancy, thus producing x rays having energy equal to the energy difference of these levels.
Bremsstrahlung x rays or deceleration radiations are produced when a nucleus is bombarded by a beam of charged particles usually electrons, as a result the beam is deflected as nucleus has positive charge. The moving particles lose their kinetic energy which is actually converted to the radiations (photons) which satisfies the law of conservation of energy. They have continuous spectrum.
X rays and gamma rays
X rays and gamma rays, both are the part of electromagnetic spectrum and both lie near to each other in spectrum. Both (x-rays and gamma rays) don’t have any charge on them. Both are part of electromagnetic spectrum. Energy of gamma rays is greater than that of x-rays. Penetration power of x-rays is less than that of gamma rays. X-rays are more intense and faster than gamma rays. Since gamma rays lie in the end of electromagnetic spectrum, so their energy is maximum. X-rays lie just behind gamma rays that’s why usually terms of x-rays and gamma rays are mistakenly mixed.
The main difference between x-rays and gamma rays is of the production source. X-rays are produced by the electronic transitions between energy levels while gamma rays are generated through the radioactive decay of an excited nucleus. Hence gamma rays are produced from excited nucleus and x rays are produced by electronic transitions.
They can be used in various fields for various purposes like
- They are used to detect the breakage in human bones.
- They are used as a scanner to scan the luggage of passengers in airports, rail terminals, and other places.
- In industry, x rays are used for detecting the defects in the welds.
- They are used for the determination of crystal structures in inorganic, organic, and biological materials.
- They are used in therapy as high-energy radiations are required to kill cancer cells by damaging their DNA.