0000000000267892
AUTHOR
Minqin Ren
showing 7 related works from this author
Objective improvement of the visual quality of ion microscope images
2013
The need to operate with low ion beam fluences implies the images obtained using ion microscope (IM) are often grainy and have poor visual quality compared to what can be obtained using e.g. confocal microscopy. This results from the Poissonian distribution of counts in pixels. Here we report work on some different approaches for objectively improving the visual quality of IM images. In this work we present (i) dramatic improvement in the visual image quality of off-axis and direct-scanning transmission ion microscopy (STIM) images by suppression of zero-pixels; (ii) denoising of PIXE images using wavelet filtering and (iii) use of the feature preserving characteristics of wavelet filtering…
WITHDRAWN: Measurement of beam focus quality in biomedical nuclear microscopy.
2009
This article has been withdrawn at the request of the author(s) and/or editor. The Publisher apologizes for any inconvenience this may cause. The full Elsevier Policy on Article Withdrawal can be found at http://www.elsevier.com/locate/withdrawalpolicy.
Exploratory nuclear microprobe data visualisation using 3- and 4-dimensional biological volume rendering tools
2007
Abstract The emergence of Confocal Microscopy (CM) and Atomic Force Microscopy (AFM) as everyday tools in cellular level biology has stimulated development of 3D data visualisation software. Conventional 2-dimensional images of cell (optical) sections obtained in a transmission electron or optical microscopes and more sophisticated multidimensional imaging methods require processing software capable of 3D rendering and mathematically transforming data in 3-, 4-, or more dimensions. The richness of data obtained from the different nuclear microscopy imaging techniques and often parallel information channels (X-ray, secondary electron, Scanning Transmission Ion Microscopy) is often not obviou…
Measurements of the stopping forces for heavy ions in Ge, Ag and Au using novel ‘polka-dot’ detectors
2006
Measurements of the stopping forces for C-14, N-14 and O-16 ions in Ge and Au, for N-14 and F-19 ions in Ag, as well as for F-19 ions in Au have been made, respectively. A novel technique, reported recently, using PIN diodes coated directly with the stopping medium in a polka dot pattern was used. This provided a set of precise, self-consistent measurements on the same stopping medium. Results show small but significant deviations from SRIM stopping predictions and are also compared to a recently-developed empirical stopping force predictor.
Characterisation of beam focus quality in biomedical nuclear microscopy: A Fourier optics approach
2009
Abstract The central peak widths of the 2D-autocorrelation function have been investigated as a Figure of Merit (FoM) of focus quality in nuclear microscopy using a quadrupole triplet lens system. The beam focus could be reliably characterised for direct scanning transmission ion microscopy (direct-STIM) images obtained with fluences as small as 5.8 × 10 9 ions cm - 2 which colocalisation tests showed did not introduce significant beam-induced changes in the cells.
Angular spreading measurements using MeV ion microscopes
2013
Abstract The sharpness of MeV ion microscope images is governed by small-angle scattering and associated lateral spreading of the ion beam in the sample. We have investigated measurement of the half-angle of the angular spreading distribution by characterising the image blurring in direct-Scanning Transmission Ion Microscopy (direct-STIM). In these tests Mylar™ foils of 0.5–6 μm were used to induce angular spreading. Images were taken of an electron microscope grid using 2 MeV protons with, and without, the foils in the beam path. The blurring was measured by fitting the width of a circular Gaussian point spread function to the images with and without the foil in position. The results show …
Angular and lateral spreading of ion beams in biomedical nuclear microscopy
2009
Abstract Nuclear scattering from target atoms gives rise to a spatial broadening of energetic ion beams penetrating matter. The spatial broadening of the ion beam presents an ultimate limit to the resolving power that can be achieved in nuclear microscopy methods. The pressing of the attainable resolution limit in biomedical nuclear microscopy to dimensions approaching 10 nm, or so, implies the fundamental limitation from ion-target scattering will become increasingly significant. This effect has been investigated by a combined analytical and numerical computational approach to determine the extent and how single and multiple scattering processes limit the resolution for analysis with 2 MeV…