Alpha vs Beta Decay
Alpha decay and Beta decay are two types of the radioactive decaying. The third type is gamma decay. All matter is made up of atoms that are made up of electrons, protons and neutrons. Protons and neutrons reside inside a nucleus while electrons revolve in orbits around the nucleus. While most of the nuclei are stable, there are some elements with unstable nuclei. These unstable nuclei are called radioactive. These nuclei eventually decay emitting a particle, thus changing into another nucleus or transforming into a nucleus with a lower energy. This decay continues until a stable nucleus is attained. There are three main types of decay called alpha, beta and gamma decay which are different depending upon the particle emitted during decay. This article intends to find out the difference between alpha and beta decay.
Alpha decay is so called as the unstable nucleus emits alpha particles. An alpha particle has two protons and two neutrons, which is also same as a helium nucleus. Helium nucleus is considered to be very stable. This type of decay can be seen with the decay of the radio active uranium 238, which after going through alpha decay transforms into more stable Thorium 234.
238U92→ 234Th90 + 4He2
This process of transformation through alpha decay is called transmutation.
When a beta particle leaves an unstable nucleus, the process is called beta decay. A beta particle is essentially an electron, though sometimes it is positron, which is also a positive equivalent of an electron. During such decay, number of neutrons goes down by one and the number of protons goes up by one. Beta decay can be understood by following example.
234Th90 → 234Pa91 +0e-1
Beta particles are more penetrating and move faster than alpha particles.
There are many differences between alpha and beta decay, which are discussed below.
Difference between alpha decay and beta decay
• Alpha decay is caused by the presence of too many protons in an unstable nucleus, while beta decay is a result of the presence of too many neutrons in unstable nuclei.
• Alpha decay transforms the unstable nucleus into another nucleus with an atomic mass 2 less than the parent nucleus and atomic number that is 4 less. In the case of beta decay, the new nucleus has an atomic mass one more than the parent nucleus but has same atomic number.
• Alpha decay produces alpha particles that are 2 neutrons and 2 protons thus having a mass of 4 amu (Atomic mass unit), and a +2 charge. Their penetrative power is weak and cannot penetrate your skin but if you consume something that is undergoing alpha decay, you may die. In general, alpha particles can be stopped even with a sheet of paper.
• Beta decay involves discharge of beta particles that are basically electrons having no mass with a negative charge. They have higher penetrative power and can easily enter your skin. Even walls cannot protect you.
• The principle of alpha decay and discharge of alpha particles is made use of in smoke detectors. It is also used in many other applications such as in generators used in space probe experiments and also as pacemakers used for treatment of heart problems. It is easier to safeguard oneself against alpha radiation than beta radiation which is more dangerous.