High-speed (up to 3 mm s-1) atomic force microscope imaging over large ranges (up to 100 mu mx100 mu m) is demonstrated using arbitrary non-raster scan paths. This scanning has been achieved by using a new approach to motion control with preprogrammed coordinates applied to a Queensgate XY-100D stage. This position-velocity-time type control gives smoother motion at high-speeds (HSs) compared to a real time control approach. Additionally a larger area of 0.5 mm x 0.7 mm is imaged by moving the HS stage on a coarse positioner and stitching data.

Image stitching is a technique that can significantly enlarge the scan area of scanning probe microscope (SPM) images. It is also the most commonly used method to cover large areas in high-speed SPM. In this paper, we provide details on stitching algorithms developed specifically to mitigate the effects of SPM error sources, namely the presence of scanner non-flatness. Using both synthetic data and flat samples we analyse the potential uncertainty contributions related to stitching, showing that the drift and line mismatch are the dominant sources of uncertainty. We also present the 'flatten base' algorithm that can significantly improve the stitched data results, at the cost of losing the large area form information about the sample.

Anemos' multi-dimensional absolute position sensors (MAPS) consists of a photolithographically defined reference scale, a camera, and computer image processing that decodes the relative position of a camera to the scale. A series of experiments tested the novel opto-electronic sensor against traceable National Physical Laboratory optical interferometers (OI) with motion provided by nanopositioning stages. Initially, MAPS to OI agreement was verified to be within 5 nm in the lateral (XY) axes across 100 mu m travel. However, when MAPS, OI, and stage position were correlated across much finer steps, MAPS demonstrated repeatability and noise below 100 pm, indicating that the larger discrepancies seen previously were due to Abbe effects, servo-mechanical, and other OI/MAPS-extrinsic factors. In a third experiment, the outputs of four orthogonally placed MAPS 6-degree-of-freedom (6DoF) sensors were correlated against each other, OI, and feedback from a single-axis stage. Here, MAPS displayed sub-nanometre agreement with other sensors, and consistency across independent MAPS sensors. A fourth experiment collected millions of MAPS sample points during repetitive 1 nm circular motion. Spectral analysis of these large datasets, correlations between noise in multiple axes and repeatability indicate MAPS may resolve single digit picometre movements. These results corroborate simulations and supports the feasibly of million-to-one position interpolation from the MAPS 5 mu m-grid reference scale. This equates to an unprecedented 40-bit dynamic range since MAPS can sustain measurement resolution over metres of travel. Overall, the experimental series highlight the challenges of nanoscale calibration and benefit of full 6DoF sensing in real-world nano-positioning systems.

Non-raster scanning can increase the scanning frame rate and measurement speed of atomic force microscopes (AFMs). It is also possible to correct the 3D drift during the non-raster scanning. However, the algorithm for the drift correction depends upon the properties of each scan pattern. While localised non-raster scanning using a rosette scan may be faster than the frequently used Lissajous scanning patterns, the drift correction is more challenging because the scan has crossing points only in local neighbouring segments where there are short temporal and spatial separations of the crossing paths. This design note presents a novel solution that successfully overcomes this problem and extends a drift correction method previously developed for Lissajous scans to the 3D drift correction of localised non-raster scanning using a rosette scan trajectory. The drift in the X, Y and Z axes can be determined using the crossing points and locally repeated scans of the same features. The general procedure is presented together with experiments using rosette scans of a two-dimensional lateral calibration standard. Experimental results have demonstrated that the method can effectively correct both the drift in the three axes and sample tilt, leading to significantly improved images. The method requires only localised crossing points in the scan and does not need additional scans to determine the three-dimensional drift based on cross-correlation and least squares techniques, and it can be used with any AFMs capable of rosette scanning.

To address the requirement for high-speed, high-resolution scanning and nanopositioning Queensgate Instruments have developed velocity control for their nanopositioning stages. This has been applied to an XY stage and its potential for use in a high-speed atomic force microscope has been assessed using the NPL Metrological High-Speed AFM platform. The work investigated the application of velocity control on image acquisition time and image resolution. Images covering scan areas and speeds in the range of of 95 μm x 95 μm (speed,500 µm/s) to 60 µm x 60 µm (speed 4 mm/sec) were acquired and showed good linearity over the scanning area and a lateral resolution of 2 nm or better. Measurements of calibration gratings are commensurate with those obtained from conventional AFMs at slower scanning speeds.

Non-raster scanning is being widely used to increase the scanning speed of atomic force microscopes (AFMs). However, like any other AFM scanning techniques, non-raster scanning can also suffer from drift during the scanning process. This paper presents a simple novel method based on cross-correlation for the effective drift correction of non-raster Lissajous AFM scans with intersecting paths. The drift in x, y and z axes can be determined using the crossing points and repeated scans of the same features. In this paper, the general method is presented together with experimental results using Lissajous scans of two artifacts, which demonstrate that the drift in the three axes and the additional tilt can all be corrected resulting in significant improvement in the image obtained. Our drift correction method can overcome the limitations of the existing AFM drift correction methods which are usually based on extra scanning, and it exploits the crossing scan paths and four scanning cycles inherent in Lissajous scanning without using additional scans to effectively determine the three-dimensional drift using cross-correlation and least squares techniques. The drift correction method can be used with any AFMs capable of Lissajous scanning.

Reliable surface thermometry of stored nuclear waste containers is essential for both health monitoring and corrosion modelling. In this paper we investigate the feasibility of using phosphor thermometry for long-term temperature monitoring of nuclear waste containers and storage racks. Two strands of research were conducted. Firstly, two thermographic phosphors (ruby and manganese-doped magnesium fluorogermanate [MFG]), mixed with six different binders were coated onto stainless steel (316L) substrates and exposed for one month to gamma radiation (gamma-ray) and sodium hydroxide (NaOH) solution. Secondly, a hybrid fibre-optic phosphor thermometer, capable of measuring these samples, was constructed and tested. The instrument can measure temperatures using both the luminescence decay time and intensity ratio techniques. Following gamma-ray and NaOH exposure, no significant degradation in phosphor appearance or performance was observed. The MFG/silicone binder combination gave the best results. The hybrid phosphor thermometer demonstrated for MFG/silicone binder that: the intensity ratio technique gave the lowest measurement standard deviation (cr(T) < 0.1 degrees C) but suffered minor drift with thermal cycling. the decay time technique (650 nm emission) did not show any drift and was capable of a measurement standard deviation of sigma(T) <= 0.3 degrees C.

Many established nuclear power producing countries are currently decommissioning first and increasingly second-generation power producing plants and fuel processing facilities. This has led to a growing inventory of different containers and packages containing radioactive waste and other nuclear materials, as well as storage of spent fuel. Here we describe research to establish in-situ yet remote health monitoring techniques based on novel temperature measurement methods for different containers and racks used to hold different nuclear waste forms, special nuclear materials and spent fuel.

In recent years, there has been growth in the development of high-speed AFMs, which offer the possibility of video rate scanning and long-range scanning over several hundred micrometres. However, until recently these instruments have been lacking full traceable metrology. In this paper traceable metrology, using optical interferometry, has been added to an open-loop contact-mode high-speed AFM to provide traceability both for short-range video rate images and large-area scans made using a combination of a high-speed dual-axis scanner and long-range positioning system. Using optical interferometry to determine stages’ positions and cantilever displacement enables the direct formation of images, obviating the need for complex post-processing corrections to compensate for lateral stage error. The application of metrology increases the spatial accuracy and linearisation of the high-speed AFM measurements, enabling the generation of very large traceable composite images.