Radioactive Decay Calculator

What is Radioactive Decay?

Radioactive decay is a natural process where unstable atomic nuclei release energy by emitting particles or waves. Think of it as an unstable atom transforming into a more stable one by "shedding" excess energy. This emission is called radiation, and it can include alpha particles, beta particles, or gamma rays. It's a fundamental concept in nuclear physics and chemistry.

Types of Decay

Radioactive decay happens in several ways, depending on how the unstable nucleus transforms. Here are the most common types of nuclear decay:

• Alpha decay (α): An atomic nucleus emits an alpha particle (which is like a helium nucleus). This reduces the atomic number and mass.
• Beta decay (β⁻, β⁺): A neutron turns into a proton (emitting an electron, β⁻) or a proton turns into a neutron (emitting a positron, β⁺). This changes the atomic number but not the mass number significantly.
• Gamma decay (γ): An excited nucleus releases energy in the form of high-energy electromagnetic waves (gamma rays) without changing its atomic or mass number.
• Electron capture: An atomic nucleus captures an inner orbital electron, converting a proton into a neutron.
• Positron emission: A proton in the nucleus transforms into a neutron, emitting a positron.

Radioactive Decay Law

The radioactive decay law describes how the number of radioactive atoms in a sample decreases over time. It's an exponential process, meaning the decay happens faster when there are more atoms. The formula helps us predict the remaining amount of a radioactive substance.

Activity of a Sample

The activity of a radioactive sample is a measure of how many atoms are decaying per second. It tells us how "radioactive" a sample is at any given moment. Higher activity means more decays are happening quickly.

• A = λN
• Where A is the activity, λ is the decay constant, and N is the number of radioactive atoms.
• Common units for activity are:
  • Becquerel (Bq): One decay per second.
  • Curie (Ci): A much larger unit, equal to 3.7 × 10¹⁰ Bq.

Applications of Radioactive Decay

Radioactive decay isn't just a theoretical concept; it has many practical and important uses in various fields:

• Carbon Dating: Scientists use the decay of Carbon-14 to determine the age of ancient artifacts, fossils, and geological formations, helping us understand Earth's history.
• Nuclear Medicine: Radioactive isotopes (radiopharmaceuticals) are used in medical imaging (like PET scans) to diagnose diseases and in radiation therapy to treat cancers.
• Power Generation: Nuclear power plants use controlled nuclear fission (a type of radioactive process) to generate electricity, providing a significant source of energy.
• Scientific Research: Radioactive tracers help researchers study biological processes, chemical reactions, and material properties in various scientific disciplines.
• Smoke Detectors: Many common smoke detectors use a small amount of radioactive Americium-241 to detect smoke particles.
• Sterilization: Gamma radiation from radioactive sources is used to sterilize medical equipment, food products, and even mail.