Nuclear fission Radionuclides are produced as an unavoidable result of nuclear fission and thermonuclear explosions. The process of nuclear fission creates a wide range of fission products, most of which are radionuclides. These neutrons activate elements placed within the reactor. A typical product from a nuclear reactor is iridium The elements that have a large propensity to take up the neutrons in the reactor are said to have a high neutron cross-section.
Cyclotrons accelerate protons at a target to produce positron-emitting radionuclides, e. The parent is usually produced in a nuclear reactor. A typical example is the technetiumm generator used in nuclear medicine.
The parent produced in the reactor is molybdenum They do so using a Geiger Mueller GM tube. The original design of the GM tube by H. Geiger and E. Mueller in A GM meter is often portable, and the efficiency of a GM for detecting radiation depends on four factors: 1. The type of radiation. The energy of the radiation. The amount of activity in the source. The direction of the source relative to the instrument detector active area. Scintillation counter Scintillation counter is an instrument for detecting and measuring ionizing radiation by using the excitation effect of incident radiation on a scintillator material, and detecting the resultant light pulses.
The scintillations are detected with the help of a photomultiplier tube that gives rise to an equivalent electric pulse. Proportion counter The proportional counter is a type of gaseous ionization detector device used to measure particles of ionizing radiation. The key feature is its ability to measure the energy of incident radiation, by producing a detector output that is proportional to the radiation energy; hence the detector's name.
Positive ion chamber. Electron central wire. In this multiplication or gas amplification, the number of ions increases exponentially. This process is cumulative and is called avalanche. Radio-activation analysis It is a most sensitive and specific technique for determination of trace quantities of wide range of elements The activity is induced in one or more elements of the sample by irradiation with suitable radiation or particles.
Most commonly thermal neutrons from a nuclear reactor source is used. Example: Neutron activation analysis NAA that samples containing certain rare earth elements became highly radioactive after exposure to a source of neutrons. From this observation, they recognized the potential of employing nuclear reactions on samples followed by measurement of the induced radioactivity to facilitate both qualitative and quantitative identification of the elements present in the samples.
There are several ways of inducing the radioactivity in the atoms present in the sample for analysis. The most common is neutron activation in which the sample is irradiated with neutrons. After the irradiation, the gamma or beta spectrum is obtained, depending on the type of emission produced by the irradiated element. During the irradiation process, radioactive nuclides are produced and emit distinctive gamma rays that are detected by gamma-ray spectrometers.
The wavelength or energy of this gamma radiation is characterizing certain radionuclides and the intensity of the radiation is used to determine the concentration of the activated element.
A specific peak in the gamma-ray spectrum corresponds to a certain element and in this way qualitatively the presence of an element is known. Further, quantitative information on the concentration of an element is obtained from the peak area.
Figure: Schematic representation of Neutron Activation Analysis In its most simple conception, the method of isotope dilution comprises the addition of known amounts of isotopically enriched substance to the analyzed sample. Mixing of the isotopic standard with the sample effectively "dilutes" the isotopic enrichment of the standard and this forms the basis for the isotope dilution method. Isotope dilution is classified as a method of internal standardization, because the standard is added directly to the sample.
In addition, unlike traditional analytical methods which rely on signal intensity, isotope dilution employs signal ratios. Owing to both of these advantages, the method of isotope dilution is regarded among chemistry measurement methods of the highest metrological standing.
Basic principle of isotope dilution -Adding of an isotopically altered standard to the sample changes the natural isotopic composition of the analyte.
By measuring the resulting isotopic composition, it is possible to calculate the amount of the analyte present in the sample. It can be used when the titrant gives an insoluble precipitate or a compound can be extracted easily, and when one of the reaction partners can be labeled. During the titration, the reagent is added in different quantities and the activity of the precipitate or the filtrate is measured, or in case of extraction the activity of one phase is determined.
There are three methods, depending the way of labeling: 1. Titration - principle, working and application. Embed Size px. Start on. Show related SlideShares at end. WordPress Shortcode. Share Email. Top clipped slide. Download Now Download Download to read offline.
Radiometric titrations Download Now Download Download to read offline. Madan Lal Follow. Types of titrations. Chemistry ivestigatory project.
Chapter AC lab 7 cover and report. Acids and bases p pt. My Chemistry Experiment. NAA Presentation. Thermometiric titration. Related Books Free with a 30 day trial from Scribd. Dry: A Memoir Augusten Burroughs. Related Audiobooks Free with a 30 day trial from Scribd. Empath Up! Arjunaa Panwar. I did and I am more than satisfied. Ii theforiginaly solution is not radioactive and the reagent'is radioactive, the reagent, when it is first added, passes into the precipitate.
There-y f y f fore, the resultantliquid is originally non-radioactive. The additiony of the silver nitrate precipitates silverchloride.
At this point the solution yis rendered radioactive by the presence of the radioactive ions of silver. The plot for determining the end-point where the'rea'gent' is radioactive and the original solution is non-radioactive is reproduced in Fig'. Near one end a tube 2l, which I may s y designate as the in-fiow tube, extends from the jacket I9 in communication with it. The tube 2i is widened at its extending end so that it has the form of a funnel and the mouth of the funnel is closed by a porous plug 23 pervious to the liquid of the solution but not to any precipitate.
In the practice of my invention, the plugged end o the tube 2l dips. At the opposite end, the jacket is provided with a second communicating tube 25, which is open to the atmosphere.
By exhausting the air from the jacket through the second tube 25, the liquid l is drawn into the jacket i9 through the plug 23 in the inow tube 2l and completely encircles the shell i7.
A ypotential is impressed between the shell il and the wire l5, and when radioactive reactions produce ionization in the container, current impulses flow between the shell and the Wire. The impulses are impressed in the input circuit of a thermionic amplier 21 and the output of the amplifier energizes a meter The meter may indicate the rate at which the ionization impulses are produced or its indicator may merely kick to indicate that an ionization impulse has been produced.
Thus, a measurement of the radioactivity of the solution. The resultant graph 3 initially extends along the 'abscissaf For ya certain quantity of reagent,. The plot for an originally radioactive solution and a non-radioactive reagent is reproduced in Fig.
In this case, the radioactivity first decreases until at the end-point it disappears because the radioactive element has passed completely into the precipitate.
The corresponding graph 3l extends from a point along the ordinate 39 to a point 4I along the abscissa 33 and then extends along the abscissa. The end-point is the point 4I at which the graph 31 meets the abscissa The reaction which is represented may be illustrated by the analysis of a. Moeller, D. Peaceful Uses of Atomic Energy , Geneva, 15 , 58 Alimarin, I. Onstott, E. Sirotina, I.
Himii , 12 , Bradhurst, B. Korenman, I. Khimii , 12 , 48 CAS Google Scholar. Duncan, J. Download references. You can also search for this author in PubMed Google Scholar.
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