[Can detect: Alpha particles only]

1. Alpha radiation can be detected using a charged electroscope as in on the left. The more intense the radiation, the faster the leaf falls. 
2. The method isn't suitable for detecting beta and gamma-radiation as these cause insufficient ionization of the air.

1. All the α-particle, β-particle and γ-ray can be detected by a photograph film.
2. The ionisation effect by the radioactive rays will decompose silver bromide crystal on the film.
3. Films are kept in the badges worn by workers as a tracer device of radioactive rays.
4. The main disadvantages of using a film as a radioactive tracer is that it needs to be processed in order to prove the presence of radioactive rays)

[Can detect: Alpha particles only]

1. A spark-chamber detector is a particle detector, that is, a device used in particle physics for detecting electrically charged particles. 
2. Spark-chamber detectors consists of metal plates placed in a sealed box filled with gas (for example, helium, neon or a mixture of the two); as a particle travels through the detector, it will ionize the gas between the plates, and a trigger system is used to apply high voltage to the plates to create an electric field immediately after the particle went through the chamber, producing sparks on its exact trajectory.

[Can detect: Alpha, Beta and Gamma]

1. The tube contains argon gas at low pressure.
2. The end of the tube is sealed by a mica 'window' thin enough to allow alpha particles to pass into the tube as well as beta and gamma radiation.
3. When a charged particle or gamma-radiation enters the tube, the argon gas becomes ionized. This triggers a whole avalanche of ions between the electrodes. 
4. For a brief moment, the gas conducts and a pulse of current flows in the circuit. 
5. The circuit includes either a scaler or a ratemeter. A scaler counts the pulses and shows the total on a display. 
6. A ratemeter indicates the number of pulses or counts per second. The complete apparatus is often called a Geiger counter.

1. Most methods of detecting alpha-, beta- and gamma-rays are based on the fact that these radiations have an ionizing effect.
2. The detectors used to detect radioactive emissions include
   1. 3 Types of Radioactive Emission
   2. Characteristics of Radioactive Emission
3. Detectors of Radiation
   1. Gold Leaf Electroscope
   2. Geiger-Muller Tube
   3. Cloud Chamber
   4. Spark-Chamber Detector
   5. Film Badge (Dosimeter)
4. Table below shows the types of emission that can be detected by different detectors

Detectors	Alpha	Beta	Gamma
Gold Leaf Electroscope
Geiger-Muller Tube
Cloud Chamber
Spark-Chamber Detector
Film Badge (Dosimeter)

Isotopes

1. Isotopes are atoms of certain elements which have the same number of protons but different number of neutrons in the nucleus of the atoms.
2. It can also be defined as atoms of certain elements with the same proton numbers but with different nucleon numbers.
3. Isotopes have the same chemical properties but different physical properties.
4. Table below shows the proton and nucleon number of the isotopes of hydrogen and oxygen.

Radioactivity

1. Radioactivity is the spontaneous process of an unstable nucleus emitting radioactive emission in order to become more stable.
2. The process is said to be spontaneous because it is neither affected by the physical condition nor the chemical composition.
3. Decay is said to occur in the parent nucleus and produces a daughter nucleus. This is a random process, i.e. it is impossible to predict the decay of individual atoms.

Radioisotopes

Isotopes of an element that undergo radioacivity is called the radioisotopes.

1. You have learn in chemistry that in an atom, electrons move around a central core called the nucleus.
2. The nucleus consists of protons and neutrons. It containing almost all the mass of the atom.
3. The nucleus of an atom is very small compared to the size of the atom
4. Protons and neutrons also known as nucleons.

Nuclide Notation

1. Proton number is defined as the number of protons in a nucleus.
2. Nucleon number is defined as the total number of protons and neutrons in a nucleus. It is also known as mass number.
3. A nuclide is a type of atom with a particular proton and nucleon number.
4. A nuclide can be represented by a nuclide notation that shows the symbol of element, proton number and nucleon number.
5. Figure below shows the nuclide notation of a nitrogen.