xCLent IV

  • Features
  • Specifications
  • Application

Features

xCLent IV is a fully integrated cathodoluminescence (CL) spectrometry system for JEOL electron microprobes (JXA-8230 and JXA-8530F). A scientific grade grating spectrometer is coupled to a high sensitivity back-thinned charge coupled detector (CCD) to provide fast light collection without compromising the electron optics or x-ray spectrometry of the EPMA. High resolution hyperspectral data is acquired during mapping by the xCLent IV - Server software, which is combined with the electron and x-ray maps for off-line analysis using the xCLent IV - Image software.

Key features:

  • Scientific grade Peltier cooled grating spectrometer
  • Hyperspectral data collection and analysis
  • Cathodoluminescence acquisition does not compromise x-ray detection or analysis geometry
  • Quantification of trace element speciation maps
  • High sensitivity due to dark noise FFT filtering
  • Selectable optical resolution - pre-aligned interchangeable entrance slits
  • Order sorting filter to remove high order reflections
  • Live map and spectrum display during mapping
  • Easy alignment of the optics
  • Multi-threaded Gaussian peak fitting
  • Luminescence database - enables the identification of cathodoluminescence peaks
  • Phase patching of x-ray data

Optics and Spectrometer

The cathodoluminescence signal is collected through the hemispherical mirror assembly in the EPMA, and is focussed into an optical fibre connected to the CL spectrometer. The Peltier cooled scientific grade spectrometer disperses the light across a back-thinned CCD, which has both high sensitivity (90% QE) and high dynamic range (14 bit ADC), allowing weak and bright signals to be collected in parallel under the same conditions. The spectrometer is sensitive to cathodoluminescence from 200 - 950 nm. Optionally, the spectrometer grating may be optimised for high-resolution spectroscopy of specific wavelength ranges on request.

xCLent IV - Server

Hyperspectral maps are collected by the xCLent IV - Server software. xCLent IV - Server shows maps collected line-by-line in real-time together with the live cathodoluminescence spectra. In mapping mode, the full CL spectrum is recorded at each point in the map, in parallel with the x-ray and electron signals that are collected by the electron microprobe. Cathodoluminescence acquisition may be synchronised with either beam or stage mapping, up to a maximum map size of 5120 × 3840 pixels, with dwell times ranging from 15 - 300ms per pixel. Typically, a dwell time of 20 - 40ms is employed, which is compatible with normal x-ray mapping conditions. xCLent IV features and improved dark noise correction using a Fast Fourier Transform (FFT) to correct for temperature drift in the CCD, which provides improved low-light sensitivity for mapping weakly luminescent materials. Maps are saved in a new hyperspectral file format (xclx) optimised for fast spectral retrieval and analysis, allowing all spectral analysis to be carried out at full spectral resolution.

xCLent IV

xCLent IV Server - Hyperspectral cathodoluminescence mapping of quartz

xCLent IV - Image

Off-line analysis of the hyperspectral cathodoluminescence and associated WDS x-ray map data is performed using xCLent IV - Image, which supports the following features:

  • Maps of cathodoluminescence intensity may be displayed from regions-of-interest (ROI) or Gaussian peak fitting
  • Display of composite maps, with the primary colour components (red, green, blue) generated from up to three different elements or cathodoluminescence ROIs
  • Scatter plots to show correlations between different elements, cathodoluminescence ROIs or fitted cathodoluminescence peaks
  • Spectra of regions within maps - or from phases within scatter plots - may be extracted for examination, identification, fitting and/or quantification
  • An integrated luminescence database that allows the emission centres responsible for CL peaks to be identified for a wide range of minerals and materials
  • Fast Gaussian peak fitting to extract cathodoluminescence peak intensities across a map
  • Fitted cathodoluminescence peaks can be calibrated using trace elemental analyses from EPMA or other sources to provide trace speciation maps (see Quantitative trace REE analysis in Scheelite by CL (PDF 116KB) application note).
xCLent IV

xCLent IV - Image. Sandstone sample showing cathodoluminescence spectra and map of quartz matrix the associated BSE and X-ray maps.

Specifications

Hardware

  • Peltier cooled scientific grade optical spectrometer with back-thinned 1044×64 element CCD
  • Signal-to-noise ratio 1000:1, Peak QE 90%
  • Dark noise 3 RMS counts
  • Symmetrical Crossed Czerny-Turner monochromators with 101mm focal length
  • Order sorting filter
  • Replaceable entrance slit - selectable optical resolution
  • Collimating lens and coupling to JEOL optical assembly
  • PC running Microsoft Windows 7 to control, capture and display data
xCLent IV

xCLent IV Peltier cooled grating spectrometer with back-thinned CCD

Software

xCLent IV - Server

  • Control software for CCD spectrometer acquisition and synchronisation with x-ray mapping
  • Supports both beam and stage scan mapping
  • Real-time spectrum view mode during mapping
  • Spectrum view mode for optical alignment

xCLent IV - Image

  • Hyperspectral map analysis and display software allowing combined x-ray and cathodoluminescence images to be presented
  • Elemental scatter plots and elemental ternary diagrams
  • Line profile analysis and display
  • Peak fitting of cathodoluminescence spectra from selectable areas
  • Cathodoluminescence peak identification of unknown lines in minerals and materials using the luminescence database
  • New hyperspectral file format (xclx) optimised for fast spectral retrieval

Options

  • Phase patching software
  • Multi-threaded Gaussian peak fitting of a map
  • Quantification of cathodoluminescence peaks
  • Additional dongle for off-line analysis of data
  • Additional spectrometers with optimised optical response for studying specific applications

Gallery