Use of proton elastic scattering techniques to determine carbonaceous fractions in atmospheric aerosols collected on Teflon filters

LABEC, the INFN ion beam laboratory of nuclear techniques for environment and cultural heritage

“…These detectors are placed in IBM geometry at scattering angles of 165°, 150° and 120° and are collimated by 1 × 13 mm 2 vertical slits set at 61 and 91 mm from the target, for the detector at 150° and for the other two, respectively; apart from this standard geometrical configuration that improves at the same time both mass resolution (with the detector placed a 165°) and depth resolution (with the detector placed a 120°), the particle detectors can be mounted at different angles, from 165° to 110° with 5° steps, at four fixed distances from the target, namely 31, 61, 91 and 121 mm. A fourth similar particle detector is placed at a 30° forward scattering angle, at 121 mm distance from the target and collimated by a 1 × 2 mm 2 vertical slit, and is used typically for hydrogen detection in aerosol samples collected on thin Teflon filters applying the Particle Elastic Scattering Analysis (PESA) technique [ 23 , 24 ]. Two X-ray detectors are used for PIXE.…”

“…An energy dispersive XRF spectrometer with three-dimensional, polarizing optical geometry and a set of secondary anodes, with automatic sample loading (Epsilon 5 by PANalytical B.V.), is used for routine analyses or coupled to PIXE in order to optimize the beam time request [ 66 ]. An organic carbon/elemental carbon (OC/EC) analyser by Sunset Inc. is also available [ 67 ]: as IBA measurements do not give information on the carbonaceous content of aerosol (or they only allow it on a few aerosol collection substrata, as reported in [ 24 ]), this kind of analyses are very important to obtain a major piece of information (carbonaceous aerosol may account for up to 50% of the aerosol mass in urban environments), complementary to the one provided by IBA in order to be able to completely reconstruct the aerosol mass (mass closure). Besides the EC/OC lab analyser, at LABEC a semi-continuous OC/EC field analyser (by Sunset Inc.) is also available for high-time-resolution campaigns, to be coupled to streaker/STRAS samplings (e.g.…”

Atmospheric aerosol analysis at the PIXE–RBS beamline in the University of Jordan Van de Graaff accelerator (JUVAC)

“…Moreover, as a further upgrade, the scattering chamber can allow the installation of a second particle detector, mounted in the forward direction at a scattering angle of 45°to implement, in the future, the use of proton elastic scattering analysis to determine the hydrogen concentration in the aerosol samples collected on Teflon filters, to be used as proxy of particulate organic matter content. [3]…”

“…A possible future upgrade of the system may include installation of a second, large area X‐ray detector, to complement the existing SDD and increase the sensitivity for mid‐ and high‐Z elements and to reach terminal voltage in the 2 to 3 MV range to further increase PIXE sensitivity and to reduce the overall measurement times, thus increasing the measurement throughput. Moreover, as a further upgrade, the scattering chamber can allow the installation of a second particle detector, mounted in the forward direction at a scattering angle of 45° to implement, in the future, the use of proton elastic scattering analysis to determine the hydrogen concentration in the aerosol samples collected on Teflon filters, to be used as proxy of particulate organic matter content …”

“…Particle‐induced X‐ray emission (PIXE) spectrometry has been successfully used for routine aerosol analysis in many laboratories, because it can detect with high sensitivity all the elements with Z > 10 and, therefore, many tracers of specific emission sources, both anthropogenic and natural. In addition, Rutherford backscattering spectrometry (RBS) has been utilized to complement PIXE in several applications, as it allows obtaining quantitative information about the concentration of C and other low‐Z atoms like N and O in the sample. Under the scope of the International Atomic Energy Agency (IAEA) regional technical cooperation project (IAEA TC project RAS/0/076) for ARASIA member states (Arab states in Asia who are members of the IAEA), The University of Jordan has been interested in studying the characteristic features of atmospheric aerosols, and hence needed to operate a PIXE–RBS combination at the University of Jordan Van de Graaff accelerator (JUVAC) facility in Amman, Jordan.…”