Radioisotopes

abhishek mishra

1. GENERAL TECHNIQUES FOR THE DETECTION OF RADIOISOTOPES Team Members Abhishek kr. Mishra [A7104421010] Nikhil Singh [A7104421016] Ritesh Pandey [A7104421012] Aryan Shukla [A7104421014] Teacher Dr. Gurjeet Kaur Subject Good lab practices and Instrumentation

2. What is Radioisotopes Radioisotopes/ radioactive isotopes of an element can be defined as atoms that contain an unstable nucleus and dissipate excess energy by spontaneously emitting radiation in the form of alpha, beta and gamma rays. A radioisotope is an isotope of an element that undergoes spontaneous decay and emits radiation as it decays. During the decay process, it becomes less radioactive overtime, eventually becoming stable. Once an atom reaches a stable configuration, it no longer gives off radiation.

3. TYPES OF RADIOACTIVE DECAY Radioactive decay is the process by which an unstable atomic nucleus loses energy by radiation. There are three types of radioactive decay: Alpha Decay ( Helium nucleus is emitted ) It’s a type of radioactive decay in which an atomic nucleus emits an alpha particle. Beta Decay ( Electrons are emitted ) It is a type of radioactive decay in which a beta particle (fast energetic electron or positron) is emitted from an atomic nucleus, transforming the original nuclide to an isobar of that nuclide. Gamma Decay ( High energy photons are emitted ) Gamma decay is the emission of electromagnetic radiation of an extremely high frequency i.e. very high energy, giving out excess energy in order to stabilize the unstable nucleus.

4. Application Of Radioisotopes Nutritional and food Science : The identification of primary and secondary food sources, elucidating predator/ prey relationship and constructing food webs. Tracing nutrient and mineral uptake by plants and animals. Determining the relative importance of plants and microbes of greenhouse gas emission from soil. Measuring environmental stressors by monitoring plant uptake of CO2 and / water. In the field of Geology Radiogenic isotopes are an extremely useful means to determine geological stratigraphy and diagenesis from geological materials. For example, working with partners in the oil and gas industry (Isotopic Ltd). We can analyse the Strontium (Sr) isotope ratio of the salts from production waters and/or cores of any vintage to characterised reservoir stratigraphy, Compartmentalisation and connectivity.

5. In chemistry -Radio Isotopic Labeling The use of isotopes is very common in Isotopic Labeling. Unusual isotopes are used as tracers or markers in chemical reactions. Atoms of an element generally cannot be distinguished from one another. These atoms can be distinguished using Mass Spectrometry or Infrared Spectroscopy, where isotopes of different masses are used. Radiations of radioactive isotopes can be used for detecting various reactants, rates, and so on in chemistry. In Industry Radioactive isotopes of various kinds are used for measuring the thickness of metal or plastic sheets; their precise thickness is indicated by the strength of the radiations that penetrate the material being inspected. They also may be employed in place of large X-ray machines to examine manufactured metal parts for structural defects. Other significant applications include the use of radioactive isotopes as compact sources of electrical power—e.g., plutonium-238 in spacecraft.

6. General Techniques for the Detection of Radioisotopes Human senses cannot detect alpha, beta or gamma radiation, so we need equipment to do this. Radioisotopes can be detected by the following: Photographic film Photographic film goes darker when it absorbs radiation, just like it does when it absorbs visible light. The more radiation the film absorbs, the darker it is when it is developed. People who work with radiation wear film badges, which are checked regularly to monitor the levels of radiation absorbed. There is a lightproof packet of photographic film inside the badge. The more radiation this absorbs, the darker it becomes when it is developed. To get an accurate measure of the dose received, the badge contains different materials that the radiation must penetrate to reach the film. These materials may include aluminium , copper, lead-tin alloy and plastic.

7. Geiger-Muller Counter A Geiger counter is a metal cylinder filled with low-pressure gas sealed in by a plastic or ceramic window at one end. Running down the center of the tube there's a thin metal wire made of tungsten. The wire is connected to a high, positive voltage so there's a strong electric field between it and the outside tube. When radiation enters the tube, it causes ionization, splitting gas molecules into ions and electrons. The electrons, being negatively charged, are instantly attracted by the high-voltage positive wire and as they zoom through the tube collide with more gas molecules and produce further ionization. The result is that lots of electrons suddenly arrive at the wire, producing a pulse of electricity that can be measured on a meter and (if the counter is connected to an amplifier and loudspeaker) heard as a "click." The ions and electrons are quickly absorbed among the billions of gas molecules in the tube so the counter effectively resets itself in a fraction of a second, ready to detect more radiation.

8. Scintillation counter Scintillation Counter is an instrument that is used for measuring ionizing radiation. It comprises the scintillator that generates photons in response to incident radiation, a PMT tube is used to convert an electronics and electric signal to process the signal. A scintillation counter is used to detect gamma rays and the presence of a particle. Autoradiography Autoradiography is a detection method in which X-ray or photographic film is exposed to emissions from radioisotopes on TLC plates to produce an image on the film. After exposure, the film is developed to reveal the location of the areas of radioactivity as darkened spots or zones of varying optical density. The density is related to the amount of radioactivity in the zone.