Proton Induced Gamma-Ray Emission PIGE

In contrast to PIXE and RBS, where forces are respectively electromagnetic and electrostatic, this kind of microanalysis uses low range nuclear forces. The analysis is based on the detection of the y-rays emitted from nuclei that are in an excited state following a charged particle induced nuclear reaction. 

The conservation of energy during the nuclear reaction analysis experiment may be expressed  

The energy of the y-rays is indicative of the isotope present, and the intensity of the y-rays is a measure of the concentration of the isotope in the sample. The limitation of this method is that, in order to have a nuclear reaction, the repulsive Coulomb barrier has to be overcome. For incident particles of energy up to 3 MeV, the only accessible elements are the light elements with Z 15 the cross-sections of the remaining elements become rapidly negligible. 

PIGE is a rapid, non-destructive technique that is employed in the analysis of light elements such as lithium (10-100 ppm limit of detection), boron (500-1000 ppm limit of detection), and fluorine (1-10 ppm limit of detection), which are often difficult to determine by other analytical means. Because the technique is based upon specific nuclear reactions, the sensitivity of PIGE varies greatly from isotope to isotope, and this non-uniformity of sensitivity has limited its widespread use as a complementary technique to micro-PIXE. 

Various additional detectors are often incorporated in a PIXE system (q.v.) to take advantage of other particle-induced processes. An intrinsic Ge(Li) or Nal(Ti) detector is often used to conduct simultaneous PIGE analysis. The latter detector has a good efficiency but a bad resolution, while Ge(Li) detectors has a poor efficiency but an excellent resolution. 

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