P. Paradis

Trace element analysis of freeze-dried blood serum by proton and alpha-induced X-rays

Abstract The absolute concentration of trace elements as Fe, Cu, Zn, and Br in blood serum has been determined by a proton-induced X-ray fluorescence technique. Proton and alpha beams of different energies were employed to bombard the targets. After a careful evaluation of the relative capabilities of each beam the actual concentration determinations were performed with a 3 MeV proton beam. Forty targets divided into two groups of twenty targets each and having mylar or formvar as backing were used in the measurements with this beam. The careful target preparation and handling plus a simple but precise method of analysis allowed to achieve an overall precision of 10% or less in the absolute concentration values of the elements. Concentration values (or limits) of weaker trace elements as Ni, As, Se, Rb, Sr, and Zr were also set. Possible improvements to increase the sensitivity of the present experimental method are discussed together with its applications in the biomedical field.

Automatic data acquisition and on-line analysis of trace element concentration in serum samples

Abstract A completely automated system has been developed to determine the trace element concentration in biological samples by measuring charged particle induced X-rays. A CDC-3100 computer with ADC and CAMAC interface is employed to control the data collection apparatus, acquire data and perform simultaneously the analysis. The experimental set-up consists of a large square plexiglass chamber in which a commercially available 750H Kodak Carousel is suitably arranged as a computer controlled sample changer. A method of extracting trace element concentrations using reference spectra is presented and an on-line program has been developed to easily and conveniently obtain final results at the end of each run.

Measurement of the static quadrupole moments of the first 2+ states in 76Se, 78Se, 80Se and 82Se☆

Abstract The reorientation effect in Coulomb excitation was employed to measure the static quadrupole moments of the first 2 + excited states in 76 Se, 78 Se, 80 Se, and 82 Se. Beams of 4 He and 16 O were used on thin highly enriched targets and the resulting spectra of the well resolved backward elastic and inelastic scattered particles were detected by four surface-barrier detectors. For constructive interference via the second 2 + excited states the determined quadrupole moments are: −0.34±0.07 e· b for 76 Se ; −0.26±0.09 e· b for 78 Se ; −0.31±0.07 e· b for 80 Se ; −0.22±0.07 e· b for 82 Se .

DETERMINATION OF TRACE POLLUTANTS IN URBAN SNOW USING PIXE TECHNIQUES.

Abstract The absolute concentrations of 25 elements in urban snow samples have been determined by PIXE techniques. Detection limits between 0.2 and 147 ppb for the following elements: Na, Mg, Al, P, Cl, K, Ca, Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Zn, As, Se, Br, Rb, Sr, Mo, Cd and Pb were achieved by a simple pre-concentration method. Proton beams of 1.6 MeV and 3.0 MeV were employed to bombard the targets. Comparisons of unconcentrated and pre-concentrated snow samples, blank determinations, sensitivity measurements vs bombarding time and reproducibility tests were also carried out.

Trace element contamination in blood-collecting devices.

Abstract We have used proton-induced X-ray emission (PIXE) methods to determine the trace-element contamination from devices commonly used for blood collection. After a qualitative evaluation of the elemental composition of the devices, we have measured the contamination in de-ionized water and plasma samples following various experimental procedures. We have found that the Vacutainer tubes are the main source of contamination, but their effect in plasma elemental analysis is significant only in the case of zinc. Use of disposable syringes to collect blood samples seems to avoid this contamination.

Asbestos pollution assessment in river water by PIXE methods

Abstract Asbestos pollution levels in river water are assessed by PIXE measurements. The application of the PIXE process in the evaluation of asbestos pollution in river water is compared with the standard measuring technique which uses an electron microscope. The data suggest that PIXE may be advantageously employed due to its simplicity of operation and analysis.

Asbestos pollution levels in river water measured by proton-induced X-ray emission (PIXE) techniques

Abstract We have used proton-induced X-ray emission (PIXE) techniques to assess the asbestos pollution of the Becancour river in Quebec. The asbestos pollution levels at twelve different sites along the river have been determined from the measured magnesium concentrations. The results clearly show that in the mining areas the asbestos pollution is high and that is decreases after the lakes located downstream. Furthermore, it has been shown that the meteorological conditions play a large role in the spread and variation of the pollution levels in river water.

High spin states and band structure in Rh99 and Rh101

High spin states in /sup 99/Rh and /sup 101/Rh have been populated via the /sup 96,98/Mo(/sup 6/Li 3n) reaction. Two cascades based on the (1/2)/sup -/ ground state and the (9/2)/sup +/ isomeric state are attributed to each nucleus on the basis of ..gamma..-..gamma.. coincidence measurements. Excitation functions and angular distribution measurements were used to assign spin values and determine some multipole mixing ratios.

Determination of sulphur in snow by proton induced X-ray emission (PIXE) method

Abstract The absolute sulphur concentration in snow samples has been determined by proton induced X-ray emission (PIXE). A proton beam of 1·6 MeV was employed to bombard the targets. A simple pre-concentration technique enables us to achieve detection limits as low as 19 ng g −1 for total sulphur concentration in snow. An overall precision of 10% was achieved. Our results confirm a recent study carried out in the same area.

High spin states and band structure in /sup 99/Rh and /sup 101/Rh

High spin states in /sup 99/Rh and /sup 101/Rh have been populated via the /sup 96,98/Mo(/sup 6/Li 3n) reaction. Two cascades based on the (1/2)/sup -/ ground state and the (9/2)/sup +/ isomeric state are attributed to each nucleus on the basis of ..gamma..-..gamma.. coincidence measurements. Excitation functions and angular distribution measurements were used to assign spin values and determine some multipole mixing ratios.