Analysis photon activation

Photon activation analysis (65)(66)(67)(68)(69) is based on the use of a nuclear reaction A( y,x)B between the atomic nuclei of the element A, which is to be determined, and the gamma photons used to activate it. 

For an appropriate choice of the incident gamma photon energy, this interaction gives rise to the production of a radioisotope B characterized by its half life and its type of radioactivity (nature and energy of particles or photons emitted). 

The gamma photons must have an energy higher than the threshold of the reaction considered, below which the reaction can absolutely not take place. 

The value of this threshold energy depends exclusively on the components of the reaction. More specifically, if the mass of the target atom A is denoted by m, that of the atom B produced by mg, and the sum of the masses of the particles x (n,p,a.) produced by the reaction by zm, the threshold energy is defined by the following formula  

The detection of radioisotope B obviously serves to obtain the data required to evaluate the concentration of element A in the irradiated sample. 

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Although following similar nuclear reaction schemes, nuclear analytical methods (NAMs) comprise bulk analysing capability (neutron and photon activation analysis, NAA and PAA, respectively), as well as detection power in near-surface regions of solids (ion-beam analysis, IB A). NAMs aiming at the determination of elements are based on the interaction of nuclear particles with atomic nuclei. They are nuclide specific in most cases. As the electronic shell of the atom does not participate in the principal physical process, the chemical bonding status of the element is of no relevance. The general scheme of a nuclear interaction is ... 

The most probable reactions occurring in photon activation analysis (PAA) are ... 

C. Segebade, H.-P. Weise and G.J. Lutz, Photon Activation Analysis, Walter de Gruyter, Berlin (1988). 

PAA Photon activation analysis PLC Preparative layer chromatography... 

Aras, N.K., Zoller, W.H., Gordon, G.E. and Lutz, G.J. (1973) Instrumental photon activation analysis of atmospheric particulate material. Analytical Chemistry, 45(8), 1481-90. 

Various other techniques that have applied to the determination of antimony in multi-cation analysis include atomic absorption spectrometry (Sect. 2.55), inductively coupled plasma atomic emission spectrometry (Sect. 2.55), neutron activation analysis (Sect. 2.55) and photon activation analysis (Sect. 2.55). 

Official methods have been published for the determination of exchangeable and extractable magnesium in soils [131]. Magnesium is extracted from the soil with 1M ammonium acetate and determined by atomic absorption spectrometry. The determination of magnesium in soils is also discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (atomic absorption spectrometry), 2.55 (inductively coupled plasma atomic emission spectrometry), 2.55 (photon activation analysis) and 2.55 (ion chromatography). 

The determination of titanium is also discussed under Multi-Metal Analysis of Soils in Sects. 2.55 (inductively coupled plasma atomic emission spectrometry), 2.55 (emission spectrometry), and 2.55 (photon activation analysis). 

Lutz, G. J. Calculation of Sensitivities in Photon Activation Analysis. Anal. Chem. 41, 424 (1969). 

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. 

Sato N, Kato T, Suzuki N. 1977. Multi-elemental determination in tobacco leaver by photon activation analysis. J Radioanal Chem 36 221-238. 

Burns R, Thomas DW and Baron VJ (1974) Reversible encephalopathy possible associate with bismuth subgallate ingestion. Br Med J 1 220—223. Chaleil D and Aliain P (1980) Effect of oral administration of bismuth subnitrate on distribution and excretion of intrapcritoneally given radiobismuth in rats. Ann Pharm Fr 37 285-290. Chattopadhyay A and Jervis RE (1974) Multielement determination in market-garden soils by instrumental photon activation analysis. Anal Chem 46(12) 1630-1639. 

The application of microtron photon activation analysis with radiochemical separation in environmental and biological samples was described by Randa et al. (2001), and both flame and plasma emission spectroscopic methods are also widely used. A more recently developed technique is that of laser-excited atomic fluorescence spectrometry (LEAFS) (Cheam et al. 1998). 

Randa Z, Kucera j and Soukal L (2001) Possibilities of simultaneous determination of lead and thallium in environmental and biological samples by microtron photon activation analysis with radiochemical separation. J Radioanal Nucl Chem 248 149-154. 

PAA Photon activation analysis involves irradiation with high energy photons (produced by conversion of electron energy into bremsstrahlung serving as the source of the photons). Photons emitted in the delayed decay are detected and used as the analytical signal. 

PAA photon activation analysis PACE pressure assisted chelation extraction... 

Charged Particle and Gamma Photon Activation Analysis... 

The analyses of the dust and salt components have been performed by various methods in our laboratory. Neutron activation analysis was used to determine Na, Mg, Al, Ti, V, Mn, Sc, Fe, Co, Sb, Ce, and Eu in dust (28). Fluoride in dust (and the K value in Table III) was done by photon activation analysis (12, 28). The salt portions of the aerosol and rainwater samples were analyzed for Na, K, Cl, and F. Sodium was determined by neutron activation and atomic absorption, potassium by atomic absorption, chlorine by titration, photon activation, and neutron activation, and fluoride by ion-specific electrode and photon activation (12, 28-30). Two analytical methods were used for Na, F, and Cl in the same samples to determine precision and accuracy. 

Kushelevsky, A., 1990. Photon activation analysis. In Alfassi, Z. (Ed.), Activation Analysis. CRC Press, Boca Raton, FL, pp. 219-237. 

Photon activation analysis can be regarded as a complementary technique to thermal neutron activation analysis, with some advantages and several drawbacks. Particularly advantageous features of photon activation analysis as compared to neutron activation include ... 

One disadvantage of photon activation analysis is the comparatively poor detection power for several elements, e.g., sodium, vanadium, cobalt, the rare-earth elements. Thus, ultratrace determinations of these elements are barely possible using photon activation. As in other instrumental analytical techniques, photon activation analysis is a relative quantification method and hence needs reference materials with known compositions. (Reference materials are dealt with below.)... 

A description of photon activation analysis including historical development can be found in the literature (see Further Reading section). 

The first photonuclear activation for analytical purposes was performed with radionuclides as the activating radiation source. These applications were reported in the early 1950s, although apparently the first beryllium determinations by photodisintegration were performed in the late 1930s in the Soviet Union. The analytical detection power of photon activation analysis using radionuclide sources is poor and restricted to the analysis of deuterium, beryllium, several fissile nuclides, and a few nuclides that have low-lying isomeric states. Nonetheless, nuclide excitation is still in use. 

Table 1 Achievable absolute detection limits in instrumental photon activation analysis...

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