U.S. Philips Corporation

Pieter K De Bokx

Jan Haisma

Paul Van Der Sluis

Nicolaas P Willard

Cornelis L Adema

Johannes F d'Achard Van Enschut

Jan C Gijsbers

Sander G Den Hartog

Bruno A Vrebos

In order to achieve suitable positional resolution for an angular scan in Grazing Exit X-ray Fluorescence (GEXRF), the sample (,) should be irradiated with a small spot (,). Consequently, the fluorescent radiation yield is low so that the duration of a measurement is comparatively long. In order to mitigate this drawback, the invention proposes the use of an analyzing X-ray mirror (,) having a line focus (,) extending perpendicularly to the sample surface (,). The line focus (,) coincides with a line-shaped PSD (,), so that every position on the PSD corresponds to a given height on the mirror, which height itself corresponds to a given take-off angle of the fluorescent radiation relative to the sample surface. Excellent positional resolution and an attractive fluorescent radiation yield are obtained by irradiating the sample by way of a focused electron beam.

Apparatus for X-ray analysis in grazing exit conditions

For TXRF (Total Reflection XRF) or GEXRF (Grazing Emission XRF) a very flat sample surface and a suitably defined region in which the sample material is present are often required. Both requirements can be satisfied by means of a (preferably synthetic) sample carrier on which a first region which has a small liquid contact angle is surrounded by a second region having a large contact angle. When applied in the first region, a droplet of solvent containing the sample material will completely wet said region, whereas the second region will not be wetted. As the solvent evaporates, the boundary of the droplet does not retreat but the first region remains fully wetted, resulting in uniform coverage of this region by sample material and also in a suitably defined sample spot.

Sample holder for a sample to be subjected to radiation analysis

A method of manufacturing an X-ray optical element. The element consists of a body of a material having a shape memory. At a high temperature, i.e. a temperature beyond the transition temperature of the material, the body is pressed so as to impart a first, desired shape. A surface of the body is thus shaped for example, as a logarithmic spiral or as another curved shape. After cooling to a low temperature, i.e. a temperature below the transition temperature of the material, a second, machinable shape is imparted to the body, preferably a flat surface. A number of precision operations can be performed on this second, machinable shape, for example polishing to a surface roughness of 0.5 nm RMS. Subsequent to this precision operation, the body is heated and resumes its first, desired shape which is retained after cooling. The body can be provided, if desired, with a comparatively thin surface layer which is also polished in the flat shape and which bends when the body resumes the desired shape. This layer can be chosen on the basis of desired mechanical (polishability) or X-ray optical properties. The X-ray optical element may comprise notably a multilayer mirror for X-ray purposes, thus forming a high- precision crystal for wavelength analysis.

Method of manufacturing an X-ray optical element for an X-ray analysis

In the case of simultaneous diffraction and fluorescence measurements in an apparatus for X-ray analysis comprising only one X-ray tube, a problem is encountered in that due to the presence of the collimators required for the fluorescence measurements only a very low X-ray power reaches the detectors, so that very long measuring times and/or an unfavorable signal-to-noise ratio occur. As a result, the detection limit for given measurements (low concentration of an element and/or light elements to be detected) becomes too high or the use of a (large and expensive) high-power X-ray tube is required. The invention utilizes a line focus tube 10 in combination with a single-slit collimator 14 for irradiating the sample 2, the fluorescence section 40 being constructed so as to have a plane or cylindrical analysis crystal 42 in combination with a location-sensitive detector 44. The diffraction measurements are performed by means of a conventional diffraction arrangement 24.

Apparatus for simultaneous X-ray diffraction and X-ray fluorescence

A method for GE-XRF (Grazing Exit X-Ray Fluorescence) with high spatial resolution in the direction parallel as well as perpendicular to the specimen surface. The specimen (2) to be examined is irradiated by means of an X-ray beam having a cross-section which is substantially larger than the surface region to be examined. This beam irradiates a large number of parts of the specimen surface and the respective radiation thus excited is measured each time. From all measurements the intensity of the radiation excited by individual pixels in the specimen is calculated by means of a suitable algorithm. The advantage of this method resides in the fact that an X-ray source having a very high intensity (for example, a synchrotron) can be dispensed with and suitable spatial resolution is achieved nevertheless.

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Eindhoven, Netherlands

Pieter K De Bokx