A completely automated PIXE analysis system and its applications

Using the 3.5 MeV proton beam from a cyclotron, a completely automated PIXE analysis system to determine the concentration of trace elements has been set up. The experimental apparatus consists of a scattering chamber with a remotely controlled automatic target changer and a Si(Li) X-ray detector. A mini-computer with a multichannel analyser is employed to record the X-ray spectrum, to acquire data and perform on-line data processing. By comparing the data recorded the internal standard and a set of reference X-ray spectra, a method of calculating the trace element concentrations and an on-line processing program have been worked out to obtain the final results in a convenient manner. The system has been applied to determine the concentrations of trace elements in lunar rock, in human serum and nucleic acids. Experimental results show that ratio of the concentration of zinc to copper in serum may be used as an important indication of the state of human health. (orig.)