For comparison, ultraviolet radiation has energy that falls in the range from a few electron volts to about eV and does not have enough energy to be classified as ionising radiation.
Alpha-, Beta- and Gamma-Ray Spectroscopy
The high energy of gamma rays enables them to pass through many kinds of materials, including human tissue. Very dense materials, such as lead, are commonly used as shielding to slow or stop gamma rays. The key difference between gamma rays and X-rays is how they are produced.
Gamma rays originate from the settling process of an excited nucleus of a radionuclide after it undergoes radioactive decay whereas X-rays are produced when electrons strike a target or when electrons rearrange within an atom. Cosmic rays also include high-energy photons and these are also called gamma-rays whether or not they originated from nuclear decay or reaction. Due to their high penetration power, the impact of gamma radiation can occur throughout a body, they are however less ionising than alpha particles. Gamma radiation is considered an external hazard with regards to radiation protection.
Similar to all exposure to ionising radiation, high exposures can cause direct acute effects through immediate damage to cells. Low levels of exposure carry a stochastic health risk where the probability of cancer induction rises with increased exposure.
Gamma radiation is released from many of the radioisotopes found in the natural radiation decay series of uranium, thorium and actinium as well as being emitted by the naturally occurring radioisotopes potassium and carbon These are found in all rocks and soil and even in our food and water. Artificial sources of gamma radiation are produced in fission in nuclear reactors, high energy physics experiments, nuclear explosions and accidents.
Gamma emitting radionuclides are the most widely used radiation sources.
The penetrating power of gamma rays has many applications. Home Understanding radiation What is radiation?
What is ionising radiation? What is non-ionising radiation?
Alpha-, Beta- and Gamma-Ray Spectroscopy
Gamma radiation Go to top of page. Gamma radiation The key difference between gamma rays and X-rays is how they are produced. Gamma radiation causes ionization of the gas in the chamber. During the moment of transition of the gamma photon through the inside of the chamber, pairs of positive and negative ions are being released, which move accordingly in the direction of the walls of the chamber and central electrode. Electrons heading towards the anode cause another processes of ionization.
The particles, which pass through the counter, cause electric discharge in the gas contained in the detector. Other materials are scintillation counters.
Scintillation counters transform the energy of ionizing radiation into the energy of light flashes scintillation. Such material for example commonly used NaI - Sodium Iodide Cristal usually cooperates with photo duplicator, which changes the energy of the light flashes into electric signal. Such detectors are used for the detection of alpha, beta or gamma radiation and their main area of application is medicine. Contemporary, commercially available cameras gamma cameras are based on scintillation detectors with the use of Bi4Ge3O12 BGO crystal.
Alpha-, Beta- and Gamma-Ray Spectroscopy - Google книги
It is a crystal of wide density range absorbs energy well , mechanically resistant and of relatively low price, but it is characterized by a long period of light impulse fading and low light efficiency. We are subjected to the radiation of natural radioactive particles always present in the earth, rocks, air and water; there is also cosmic radiation pervading into the atmosphere from the cosmic space. Sources of radiation created by humans: -accelerators -nuclear reactors - various types of military and cosmic solutions - defectoscopes and smoke sensors which contain isotope sources -Roentgen apparata and devices for tellegammatherapy -transport and radioactive waste dumps - various building materials, e.
The interaction of gamma radiation with matter consists in many different processes in which the photons interact with electrons, nuclei within electromagnetic field. The effect of ionic radiation on living organisms is connected with the influence of the ray on living cells. If the radiation reaches the parts important for the living functions, such as DNA particles, the cell damage will be greater than in the case when it will interact with less important particles, such as for instance water particles.
The most susceptible to radiation are those cells, which reproduce quickly. We encourage the participants to bring a device, which emits electromagnetic waves or some way of recording tape or digital sound recorder, camera, headphones, computer with PD or Supercollider installed etc. All the materials will be provided and are included in the registration fee.