A possible application of the new curium based XPIXE-alfa system to the monitoring of the atmospheric particulate matter

The Radioisotope 244Cm emits 5.76 and 5.80 MeV alpha particles; also 9% yield of x-rays are emitted in the energy range of 12.13 to 21.98 keV. A spectrometer based on the use of curium source has been widely used during the Mars explorations. At the LNS/INFN laboratories of Catania a portable curium based spectrometer, named XPIXE-alpha system, has been designed and realised. The main characteristics of the new portable XPIXE-alpha spectrometer are described. PIXE and XRF mechanisms are simultaneously induced on samples being analysed. Due to the different behaviour of the ionisation cross section of alpha particles and x-rays this source enables to well excite both light elements and medium ones. The above characteristics are particularly suited for the analysis of atmospheric particulate matter in which major light elements are tracers of the crustal component (Si, Al, Ca and Fe) or tracers of the sea water component (Na and Cl) or as aerosol secondary component (S). Results of low intensity prototype are presented and limitations are discussed.