a new device for the simultaneous application of pixe and xrf in

A NEW DEVICE FOR THE SIMULTANEOUS APPLICATION OF PIXE AND
XRF IN VACUUM
1,2
1
Javier Miranda , Juan Reyes-Herrera , Óscar G. de Lucio
1
1 Instituto de Física, Universidad Nacional Autónoma de México
Circuito Investigación Científica S/N, Ciudad Universitaria, 04510 México, D.F., Mexico
{miranda@fisica.unam.mx}
2 Centro de Ciencias de la Atmósfera, Universidad Nacional Autónoma de México
Circuito Investigación Científica S/N, Ciudad Universitaria, 04510 México, D.F., Mexico
ABSTRACT
The analytical techniques Particle Induced X-ray Emission (PIXE) and X-Ray Fluorescence (XRF) have
been shown to be very powerful for the non-destructive multielemental analysis samples of interest in
many sciences [1]. It has been found that both of them have limitations in the atomic number range of
analyzed elements, because of their sensitivity. This way, PIXE appears to be more sensitive to light
elements (Al to Zn) due to the steep decrease of ionization cross sections by the impact of protons on
heavier elements [2]. On the other hand, XRF based on x-ray tubes is more sensitive to elements with
atomic numbers above around 26 (Fe) and up to roughly Zr, due in this case to the photoelectric cross
sections.
In this work, then, a device for the simultaneous application of PIXE and XRF is presented. The system
has a more uniform response for elemental analysis of atmospheric aerosol samples. It was installed in the
x-ray beam line of the Instituto de Física 5.5 MV Van de Graaff accelerator, which produces 1.5 MeV to
2.0 MeV proton beams for PIXE. XRF analysis is performed with a low power 50 kV tube, Ag anode.
Results about the operation of the spectrometer are shown. Possible applications in basic studies of
characteristic x-ray emission processes are exemplified, as well as preliminary analyses of PM10 samples
collected in Mexico City.
Keywords: Particle Induced X-ray Emission; X-Ray Fluorescence; Atmospheric Aerosols
Acknowledgements
The authors acknowledge the partial support of DGAPA-UNAM (contract IN1000812) and the Atmospheric Aerosols group at
CCA-UNAM.
Reference
[1] Landsberger, S., Creachman, M., 1999. Elemental Analysis of Airborne Particles, CRC Press, Boca Raton, FL.