Prompt gamma neutron activation

Z.B. Alfassi and C. Chung (eds), Prompt Gamma Neutron Activation Analysis, CRC Press, Boca Raton, FL (1995). 

Figure 2.13 Schematic diagram of the nuclear processes involved in neutron activation analysis. Prompt gamma neutron activation analysis (PGNAA) occurs within the reactor delayed gamma NAA (DGNAA) occurs at some remote site. (After Glascock, 1994 Fig. 1. John Wiley Sons Limited. Reproduced with permission.)...

The y particle is emitted virtually instantaneously on the capture of the neutron, and is known as a prompt y - it can be used analytically, in a technique known as prompt gamma neutron activation analysis (PGNAA), but only if such y s can be measured in the reactor during irradiation. Under the conditions normally used it would be lost within the nuclear reactor. In this reaction, no other prompt particle is emitted. The isotope of sodium formed (24Na) is radioactively unstable, decaying by beta emission to the element magnesium (the product nucleus in Figure 2.13), as follows ... 

Prompt gamma neutron activation analysis (PGNAA)... 

TNPGNAA thermal neutron prompt gamma neutron activation analysis TOF-MS time of flight mass spectrometry toxicokinetics study of the quantitative action of a poison in an organism over a period of time, especially the processes of absorption, distribution, biotrans formation and excretion... 

Prompt gamma neutron activation analysis is a process similar to INAA that was discussed in Section 3. While INAA uses the radioactivity emitted by the activation products for analysis, PGNAA uses the prompt gamma rays emitted during the neutron capture. 

Many facilities use a prompt gamma neutron activation analysis (PGNAA) system to measure boron in blood samples although there are other methods. 

Figure 1. Histogram of detection limits for neutron activation analysis (NAA) and neutron-capture prompt gamma-ray activation analysis (PGAA). Data from Reference 15.

Neutron-capture prompt-gamma ray activation analysis (PGAA) is a recent addition to the nuclear analytical arsenal. In this technique the instantaneous gamma ray emission from a sample is measured as it is irradiated in a flux of reactor neutrons (33,3, 35). Because the sample must be several meters from either the core of the reactor or (less commonly) from the detector, the sensitivity of this technique is generally poorer than in conventional NAA. However, it is possible to measure small quantities of many elements which do not give radioactive neutron-capture products, notably 0.01 mg of H, 50 ng B, and 1 mg P in an electronics context. 

Andeeson DL (2000) Neutron capture prompt gamma-ray activation of meat homogenates. J Radioanal Nud Chem 244 225 - 229. 

This can result in a radioactive product from the A(n, t)A reaction where A is the stable element, n is a thermal neutron, A is the radioactive product of one atomic mass unit greater than A, and y is the prompt gamma ray resulting from the reaction. A is usually a beta and/or gamma emitter of reasonably long half-life. Where access to a nuclear reactor has been convenient, thermal neutron activation analysis has proven to be an extremely valuable nondestructive analytical tool and in many cases, the only method for performing specific analyses at high sensitivities... 

Glascock, M.D., Spalding, T. G., Biers, J. C., and Corman, M.F. (1984). Analysis of copper-based metallic artefacts by prompt gamma-ray neutron activation analysis. Archaeometry 26 96-103. 

The prompt gamma-rays emitted following neutron or charged particle interactions with the target nuclide may be used as a basis for non-destructive analyses. The important advantage of this technique is that the determination does not depend in any manner on the half-life of a product radionuclide. In fact, using this technique, the product nuclide need not even be radioactive. Many conventional activation determinations are limited in their sensitivities by short half-life product radionuclides, or the fact that the most abundant or highest cross section isotope of the element to be determined leads to a stable product on irradiation. 

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. 

Prompt gamma-activation analysis and neutron activation-mass spectrometry techniques have been developed that can accurately measure boron in biomaterials (Anderson et al. 1990, 1994). One major... 

Anderson DL, Cunningham WC and Mackey EA (1990) Neutron capture prompt-gamma activation analysis of foods. Biol Trace Elem Res 27 613-622. 

Instrumental neutron activation analysis (thermal, INAA epithermal, EINAA, prompt gamma PGNAA) (INAA)... 

Some relevant terms for activation analysis are activation analysis, neutron activation analysis (NAA), instrumental neutron activation analysis (INAA), neutron activation analysis with radiochemical separation (RNAA), photon activation, neutron capture prompt gamma activation analysis (PGAA), charged particle activation, autoradiography, liquid scintillation counting, nuclear microprobe analysis, radiocarbon (and other element) dating, radioimmunoassay, nuclear track technique, other nuclear and radiochemical methods. Briefly, the salient features of some of the more popular techniques are as follows ... 

TNPGAA thermal neutron prompt gamma activation analysis... 

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