In the last decade the non-destructive determination of the elemental distribution assumed a relevant role in material sciences. Generally, the elemental mapping of the samples is determined by the well-known ?XRF method that allows to obtain 2D/3D chemical images with high spatial-resolution. An alternative way to operate is represented by the Full Field X-Ray Fluorescence (FF-XRF) technique. It consists in the irradiation of the samples with a broad X-ray beam and in the detection of the induced X-ray fluorescence by means of a position-sensitive detector, through the use of a pinhole-collimator or an X-ray optic. Until now the application of this method was limited by the low-energy resolution of the detectors installed in the FF-XRF systems recently developed. In this paper we present a new X-ray pinhole camera for FF-XRF measurements with high-energy and high-spatial resolution. It consists of a back-illuminated and deep depleted CCD detector (1024x1024 pixels; 13 ?m pixel size) coupled to a 70 ?m pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values. The characteristic X-Ray fluorescence is induced on the samples by irradiation with a low-power X-ray tube (max. 50 kV and 2 mA). The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated in the energy working-domain of the CCD detector (0.2 keV-30 keV). The characteristic X-ray spectra were obtained by using a multi-frames acquisition in single-photon counting and by a proper processing of the acquired images. The energy resolution measured at the Mn-K? line is 139 eV. The spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. It was determined at the magnification values of 3.2x and 0.8x, taken as testing values respectively for measurements of small-dimension samples (4x4 mm2) and of large-dimension samples (4x4 cm2). The obtained values were 90 ?m at 3.2x and 190 ?m at 0.8x. FF-XRF measurement time for detecting the major elements is in the range of 1-2 hours .
FULL FIELD X-RAY FLUORESCENCE WITH HIGH ENERGY AND HIGH SPATIAL RESOLUTION
FP Romano;
2013
Abstract
In the last decade the non-destructive determination of the elemental distribution assumed a relevant role in material sciences. Generally, the elemental mapping of the samples is determined by the well-known ?XRF method that allows to obtain 2D/3D chemical images with high spatial-resolution. An alternative way to operate is represented by the Full Field X-Ray Fluorescence (FF-XRF) technique. It consists in the irradiation of the samples with a broad X-ray beam and in the detection of the induced X-ray fluorescence by means of a position-sensitive detector, through the use of a pinhole-collimator or an X-ray optic. Until now the application of this method was limited by the low-energy resolution of the detectors installed in the FF-XRF systems recently developed. In this paper we present a new X-ray pinhole camera for FF-XRF measurements with high-energy and high-spatial resolution. It consists of a back-illuminated and deep depleted CCD detector (1024x1024 pixels; 13 ?m pixel size) coupled to a 70 ?m pinhole-collimator, positioned between the sample under analysis and the CCD. The X-ray pinhole camera works in a coaxial geometry allowing a wide range of magnification values. The characteristic X-Ray fluorescence is induced on the samples by irradiation with a low-power X-ray tube (max. 50 kV and 2 mA). The spectroscopic capabilities of the X-ray pinhole camera were accurately investigated in the energy working-domain of the CCD detector (0.2 keV-30 keV). The characteristic X-ray spectra were obtained by using a multi-frames acquisition in single-photon counting and by a proper processing of the acquired images. The energy resolution measured at the Mn-K? line is 139 eV. The spatial resolution of the pinhole camera was measured by analyzing the profile function of a sharp-edge. It was determined at the magnification values of 3.2x and 0.8x, taken as testing values respectively for measurements of small-dimension samples (4x4 mm2) and of large-dimension samples (4x4 cm2). The obtained values were 90 ?m at 3.2x and 190 ?m at 0.8x. FF-XRF measurement time for detecting the major elements is in the range of 1-2 hours .I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
