Gamma spectroscopy method

Gamma spectroscopy is a radiochemistry measurement method which determines the energy and count rate of gamma rays emitted by radioactive substances. 

Gamma spectroscopy is a radiochemistry measurement method that determines the energy and count rate of gamma rays emitted by radioactive substances. Gamma spectroscopy is an extremely important measurement. A detailed analysis of the gamma ray energy spectrum is used to determine the identity and quantity of gamma emitters present in a material. 

Direct estimation of a number of elements without separation is a perfectly feasible method provided that the activity induced in the matrix material during irradiation is not excessive. Resolution of decay curves alone is not likely to be w idely applicable, but if this is accompanied by gamma spectroscopy the utility of the method is considerably extended. Morrison and Cosgrove 63) determined Zn, As , Fe , and Na ... 

Gamma spectroscopy is a radiochemical measurement method that allows identification and quantitative determination of activity of radionuclides, which emit gamma radiation or x-rays. The equipment used in gamma spectroscopy includes an energy-sensitive radiation detector, such as semiconductors, scintillators or proportional counters, and a multichannel analyzer. The energies and the photon yields are characteristic for specific nuclides. 

Along with the maturity of gamma spectroscopy equipment, the extension of the method to heavier elements, as happened in the 1960s, was straightforward. 

Neutron Activation Gamma Spectroscopy (NA) 1.5 In vivo (liver). Ellis et al. (1983)... Only available in vivo method for direct determination of cadmium body tissue burdens e ensive absolute determination of cadmium in reference materials. 

The set of measurements of dose rates performed at various locations where members of the critical group usually reside, both outdoors and indoors, can be used directly to assess the existing external doses. To define the contribution of a particular radiation source to the external dose, methods of field gamma spectroscopy should be apphed with subsequent assessment of the dose due to particular radionuclides or subtraction of the background radiation as determined in similar conditions. 

Bekker, A.A., Zhukov, Yu.M, Kaukis, A.A., Nesmeyanov, A.N. (1973). Tin telluride study using gamma-resonance spectroscopy method. Vestnik Moskaoskogo Unto., Ser. Khimiya, No. 4, (1973), pp. 434M36, ISSN 0579-9384. 

One of the limitations of the portable field survey instruments in the measurement of americium is that their quantitative accuracy depends on how well the lateral and vertical distribution of americium in the soil compares with the calibration parameters used. These methods can provide a rapid assessment of americium levels on or below surfaces in a particular environment however, laboratory-based analyses of samples procured from these environmental surfaces must be performed in order to ensure accurate quantification of americium (and other radionuclides). This is due, in part, to the strong self absorption of the 59.5 keV gamma-ray by environmental media, such as soil. Consequently, the uncertainty in the depth distribution of americium and the density of the environmental media may contribute to a >30% error in the field survey measurements. Currently, refinements in calibration strategies are being developed to improve both the precision and accuracy (10%) of gamma-ray spectroscopy measurements of americium within contaminated soils (Fong and Alvarez 1997). 

Methods utilizing characteristic physical properties have been developed for several chlorinated hydrocarbon insecticides. Daasch (18) has used infrared spectroscopy for the analysis of benzene hexachloride. By this means it is possible to determine the gamma-isomer content, as well as that of the other isomers of technical benzene hexachloride, provided the product is substantially free of the higher chlorinated cyclohexanes. 

Other frequently used methods for determining fluoride include ion and gas chromatography [150,204,205] and aluminium monofluoride (AIF) molecular absorption spectrometry [206,207]. Less frequently employed methods include enzymatic [208], catalytic [209], polarographic [210] and voltammetric methods [211], helium microwave-induced [212] or inductively coupled plasma atomic emission spectrometry [213], electrothermal atomic absorption spectrometry [214], inductively coupled plasma-mass spectrometry [215], radioactivation [216], proton-induced gamma emission [217], near-infrared spectroscopy [218] and neutron activation analysis [219]. 

Methods for Determining Biomarkers of Exposure and Effect. As discussed above, the presence of radium in biological materials is usually determined by virtue of its radioactivity. Methods available for the determination of radioactivity in biological materials include alpha spectroscopy and gamma spectrometry, which is more convenient, but generally less sensitive, than alpha spectroscopy (Joshi 1987). It would be useful to have additional data on the sensitivity and accuracy of the methods that are currently in use. 

However this does not mean that gamma-ray transitions in such nuclei are easy to detect. Usually we confront the competition of many nuclear reaction channels, which makes in-beam gamma-ray spectra too composite to analyze. In-beam gamma-ray spectroscopy through heavy-ion fusion is longing for a new method of selectively observing gamma-rays emitted via a nuclear reaction channel of particular interest. 

Fer65] Ferguson AJ 1965 Angular correlation methods in gamma-ray spectroscopy (North-Holland, Amsterdam). 

Wap66] Wapstra AH 1966 The coincidence method, in Alpha-, beta- and gamma-ray spectroscopy, Vol. I, ed. K. Siegbahn (North-Holland, Amsterdam) p. 539. 

Hoogenboom, A. M. A New Method in Gamma-Ray Spectroscopy A Two Crystal Scintillation Spectrometer with Improved Resolution. Nucl. Instr. 3, 57 (1958). 

Mossbauer spectroscopy is a nuclear resonance technique and is therefore restricted to particular isotopes with suitable combinations of properties. The severest limitation is the need for gamma-radioactivity, which limits the method to the heavier elements (Z > 18). Amongst the halogens, measurements are possible only for iodine. 

Radionuclidic purity is determined by measuring the characteristic radiations emitted by individual radionuclides. Gamma emitters are distinguished from another by identification of their y energies on the spectra obtained from a Nal crystal or a Ge (germanium) detector. This method is called y spectroscopy. 

The basic information in the study of sorption processes is the quantity of substances on the interfaces. In order to measure the sorbed quantity accurately, very sensitive analytical methods have to be applied because the typical amount of particles (atoms, ions, and molecules) on the interfaces is about I0-5 mol/m2. In the case of monolayer sorption, the sorbed quantity is within this range. As the sorbed quantity is defined as the difference between quantities of a given substance in the solution and/or in the solid before and after sorption processes (surface excess concentration, Chapter 1, Section 1.3.1), all methods suitable for the analysis of solid and liquid phases can be applied here, too. These methods have been discussed in Sections 4.1 and 4.2. In addition, radioisotopic tracer method can also be applied for the accurate measurement of the sorbed quantities. On the basis of the radiation properties of the available isotopes, gamma and beta spectroscopy can be used as an analytical method. Alpha spectroscopy may also be used, if needed however, it necessitates more complicated techniques and sample preparation due to the significant absorption of alpha radiation. The sensitivity of radioisotopic labeling depends on the half-life of the isotopes. With isotopes having medium half-time (days-years), 10 14-10-10 mol can be measured easily. 

The most utilized methods include X-ray fluorescence (XRF), atomic absorption spectroscopy (AAS), activation analysis (AA), optical emission spectroscopy (OES) and inductively coupled plasma (ICP), mass spectroscopy (MS). Less frequently used techniques include ion-selective electrode (ISE), proton induced X-ray emission (PIXE), and ion chromatography (IC). In different laboratories each of these methods may be practiced by using one of several optional approaches or techniques. For instance, activation analysis may involve conventional thermal neutron activation analyses, fast neutron activation analysis, photon activation analysis, prompt gamma activation analysis, or activation analysis with radio chemical separations. X-ray fluorescence options include both wave-length and/or energy dispersive techniques. Atomic absorption spectroscopy options include both conventional flame and flameless graphite tube techniques. 

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