Photon-tagged nuclear reaction analysis for trace element determination

The new trace element measurement technique ''photon-tagged Nuclear Reaction Analysis'' (pNRA) is introduced and the experimental procedures are described in detail. The pNRA-technique is an ion-beam analytical technique intended for the determination of the abundance of the lightest elements, ranging from lithium to phosphorus. The technique is a complement to the PIXE technique. pNRA is a multiparameter technique, using fast coincidence criteria and high time resolution which identifies and measures the products of nuclear reactions from which the amount of an element in the irradiated target can be determined. A detection system suitable for use in pNRA analysis is described. Different aspects of experimental parameters, e.g. time resolution and gamma-efficiency, are discussed and evaluated. Yield curves for all relevant light isotopes are presented for a proton beam energy between 3.5 and 3.75 MeV, and minimum detection limits (MDLs) are extracted for different environments. The results of the MDL measurements with pNRA are compared with the detection limits of other frequently used techniques such as proton-induced gamma-emission (PIGE) and particle elastic scattering analysis (PESA), and are shown to match these other techniques very well. (C) 1997 Elsevier Science B.V.