MULTI-PURPOSE, HIGH RESOLUTION THETA / THETA X-RAY DIFRACTOMETER
Flexibility and Modularity Without Limits
EXPLORER is a multi-purpose – Theta/Theta – high resolution diffractometer. Has a direct drive torque motors that ensure best performances in various analytical areas, from phase analysis to determination of micro-structural properties on bulk or thin film materials.
The wide range of accessories and attachments allows performing measurement in different settings such as:
EXPLORER XRD is flexible and alignment-free modular instrument. It can be modified and upgraded depending customer’s requirements. GNR has a very wide range of accessory selections such as X-ray sources, optics, sample holders, detectors and configurations to satisfy all the analytical needs.
EXPLORER XRD can exceed customers’ needs with no limit of applications and offers high performances in all analytical areas, ranging from phases quantification of mixtures, to the determination of microstructural properties as residual stress and preferred orientation of crystallites on bulk materials as well as on thin films.
Applications & Configurations
X-RAY POWDER DIFFRACTION (XRPD)
Phase analysis and identification is the study of the different polycrystalline materials within an analytical samples. One phase is separated from another due to its unique powder diffraction pattern which arises from its unique combination of composition and crystal structure.
The analysis is applicable to all types of crystalline materials and can be restricted to identification only or extended to full quantitative analysis.
Thin Film (GIXRD)
In phase analysis of thin films or multilayers, measurements can be done at low glancing angles of the X-ray beam to increase the intensity of the signal from the layers and to decrease the substrate reflections. During the measurement the incident angle remains fixed while the detector is scanned through the 2-theta range. In this configuration a parallel beam collimator (LESS) is attached on the reflected beam.
GIXRD (Grazing Incidence Diffraction) Configuration
Thin Film (XRR)
The EXPLORER can accomplish in a single measurement the characterisation of thin film layer thickness, density, surface and interface roughness. If the films are single or multilayer, only a few atoms or up to 500 nm thick, the procedure is fast, easy and completely non destructive.
The knife edge collimator ensures optimum collimation of the primary beam without the intensity reduction typical of crystal monochromators.
XRR (Reflectometry) Configuration
Small Sample Quantities (Capillary Technique)
The capillary technique is ideal for examining small sample quantities or air-sensitive samples in a closed environment. Thanks to the parabolic mirror and the CeleriX Detector the EXPLORER diffractometer produces high-quality diffractograms in an extremely short time, even with small sample quantities. A precise goniometer head which is aligned under microscope control guarantees coincidence of capillary and diffractometer axis.
SAXS & WAXS Analysis
The small-angle X-ray scattering (SAXS) technique is the ideally suited for the structural characterization of nanoscaled materials, and among others, allows for nanoparticle and pore size analysis and specific surface area determination.
Setups for SAXS measurements require a narrow, highly collimated and intense X-ray beam, the effective suppression of any parasitic scattering, and a detector with a high linearity range. The objective is to measure the scattered intensities in the immediate vicinity of the direct beam, typically down to 0.1 deg and below. The smallest accessible scattering angle determines the upper limit of the dimension (e.g. particle diameter) that can be studied
SAXS is applied to investigate structural details in the 0.5 to 50 nm size range in materials such as:
Texture analysis is a diffraction technique in which the orientation distribution of the crystallites constituting a sample is determined.
In polycrystalline solid materials, such as a wide class of metals and ceramics, the orientation of the crystallites is not usually distributed randomly, like in an ideal powder specimen. In most cases, a preferred orientation of the crystallites with respect to the sample reference frame is present. In materials science this is referred to as texture. Knowledge of the texture is an important factor in understanding the mechanical, physical or chemical behavior of the material investigated.
In X-ray diffraction analysis, the texture is determined from a set of pole figures. These pole figures are measured by recording the intensity distribution of a single (hkl) reflection by tilting and rotating the sample over the orientation sphere. In this way the orientation distribution of a single reflection, and thus for a single lattice plane, is determined. When a set of pole figures for independent crystal orientations has been measured, the orientation distribution function (ODF) of the crystallites can be calculated.
Texture analysis is applied in a wide range of application areas such as materials science, geology, archeology and mineralogy.
X-ray diffraction is commonly used to measure a materials crystal structure, crystal lattice orientation, and the spacing of the lattice planes. Explorer are designed to measure the spacing of a specifically selected lattice plane reflections for a given material. Explorer use various X-ray tubes selected to optimize these measurements for ferritic steel, stainless steel, aluminum, or magnesium alloys. Explorer tracks the lattice spacing from the initial to current spacing while the specimen is under applied load in the plane of the sheet. By tilting the samples from the normal direction of the sheet toward the direction of loading the distribution of strains can be measured and used to derive the full stress tensor just inside the sheet surface.
In transmission X-ray diffraction experiments, the incident X-ray beam is not reflected by the sample, but instead travels through the sample, where the diffraction process takes place.
Materials consisting of light atoms, such as organic compounds from the pharmaceutical or polymer industries, are “transparent” for X-rays. When X-ray diffraction experiments are performed on these materials in the Bragg-Brentano geometry, a large specimen displacement will occur as a result of the high transparency of the sample. In these cases transmission experiments are advised.
In the transmission geometry the X-ray beam, coming off the focus of the X-ray tube, is focused on the detector by an incident beam conditioner – an X-ray mirror, for instance. The foil sample is placed perpendicular to the diffraction plane in the incident beam. The X-ray beam is diffracted over the Bragg angle and focused on the detector on the 2Theta circle.
Transmission experiments can also be performed on samples in glass capillaries. The purpose of capillary samples is to allow the accurate measurements of small amounts of powder, which should not be exposed to air, or which are dangerous to the operator’s health. Spinning of the samples brings more crystallites into the diffraction condition and reduces the influence of particle statistics on the measurements.
High resolution powder & crystallography
Pure Ka1 radiation for Highest resolution on the market, indexing, cell refinement, complex mixtures
Non-ambient diffraction is the general term used for X-ray diffraction experiments performed at atmospheric conditions other than those normally existing in a laboratory environment.
Non-ambient diffraction experiments give information about the changes in the sample as a function of temperature, pressure or gas phase composition. Under changed atmospheric conditions, samples may show crystallographic phase transitions or they may perform chemical reactions with the gas phase. X-ray diffraction is non-destructive and gives unambiguous information about rearrangements in the crystal structure under changing environmental conditions.
There are several reasons to study materials in non-ambient conditions: