Microscopy & Microanalysis Instruments

Detailed information about our state-of-the-art instruments.

Variable Pressure SEM

Martin Pueschel © Australian Museum

Scanning Electron Microscope

Zeiss EVO LS 15 SEM: Variable Pressure SEM
 
  • Tungsten gun
  • Everhart-Thornley Secondary Electron Detector
  • Zeiss VPSE G3 detector
  • Robinson Backscatter Detector
  • Zeiss Backscatter Detector
  • ADDA III SEM/STEM Scan Interface

The Variable Pressure SEM allows the examination of surfaces of almost any specimen, wet or dry, insulating, uncoated and untreated because the environment around the specimen no longer has to be at high vacuum. The environment can be water vapour or other gases in the pressure range from 10 to 3,000 Pa.

When the Pressure Limiting Apertures are fitted in the final aperture of the column, a controllable amount of gas molecules, usually air, can be introduced into the specimen chamber whist maintaining a good vacuum in the electron optical column and the electron gun. Collisions between the high energy electrons of the beam and the gas molecules will cause the gas to ionise. The positive ions that are produced will neutralise the negative charge that has formed on the surface of an insulating material and will enable disturbance free images of the specimen to be obtained. The secondary electrons (SE) and backscattered electrons (BSE) passing through the gas will interact with the molecules and cause photos of light to be emitted. These photons can be collected by a VPSE detector or a BSE detector to give an image of the surface of the specimen similar to that produced by SE and BSE detectors under high vacuum.

The introduction of water into the chamber slows down the dehydration of specimens containing water and helps maintain the shape of the specimen.

X-ray Powder Diffraction System

PANanalytical X’Pert Pro XRD
 
  • PW3050/60: Theta 2 Theta with Flat sample stage, Sample stage spinner, fixed divergence split line optics assembly, width mask (20mm, 15mm, 10mm, 5mm), Divergence slit (4 deg, 2 deg, 1 deg, ½ deg, ¼ deg), Scatter-slit (4 deg, 2 deg, 1 deg, ½ deg, ¼ deg), fixed slit interface, High score plus software with ICCD PDF-4/ Minerals 2009 database.

X-ray diffraction is a common technique for the study of crystal structures and atomic spacing. The PANanlytical X’Pert Pro XRD is a theta to theta goniometer system. The sample stays at the levelled position during the measurement.

X-ray diffraction is based on constructive interference of monochromatic X-rays and a crystalline sample. These X-rays are generated by a cathode ray tube, filtered to produce monochromatic radiation, collimated to concentrate, and directed towards the sample. The interaction of the incident rays with the sample produces constructive interference (and a diffracted ray) when conditions satisfy Bragg’s Law (nλ= 2d sinθ). This law relates the wavelength of electromagnetic radiation to the diffraction angle and the lattice spacing in a crystalline sample. These diffracted X-rays are then detected, processed and counted. By scanning the sample through a range of 2θangles, all possible diffraction directions of the lattice should be attained due to the random orientation of the powdered material. Conversion of the diffraction peaks to d-spacings allows identification of the material because each mineral has a set of unique d-spacings. Typically, this is achieved by comparison of d-spacings with standard reference patterns.

All diffraction methods are based on generation of X-rays in an X-ray tube. These X-rays are directed at the sample, and the diffracted rays are collected. A key component of all diffraction is the angle between the incident and diffracted rays.

What is X-ray powder diffraction good for? X-ray powder diffraction is most widely used for the identification of unknown crystalline materials. Determination of unknown solids is critical to studies in: geology, environmental science, material science, engineering and biology.

Other applications include: Characterization of crystalline materials; Identification of fine-grained minerals such as clays and mixed layer clays that are difficult to determine optically.

Portable XRF Analyzer

  • Bruker AXS Handheld Tracer IIIV system

SEM Specimen Preparation

  • Critical Point Dryer - BAL-TEC CPD 030
  • Gold Sputter Coater Unit – EMITECH K550
  • Carbon Coater Unit – EMITECH K250
  • Mini Freeze Drier – Dynavac
  • Sonicator
  • Ovens

Light Microscopes and Image Capturing Systems

  • Leica MZ 16 stereo dissection microscopes
  • Leica MZ 16 stereo microscope with polarization and transmitted light base
  • Olympus BX50 Microscope with polarization, DIC, 100x UPlanFl oil, 40x UPlanFl, 20x UPlanFl, 10x UPlanFl.
  • Leica 35mm camera system
  • Spot Flex Digital Camera System
  • Nikon D3X, Canon D7 Micro Imaging System with Infinity Long Distance Microscope tube and Objectives (CF2, CF3, CF4, CF5, HDF2). ML-1000 illuminator, Micro Nikkor 105mm f/2.8D and 60mm f/2.8D lens, Canon EFS 18-200mm f/305-5.6 IS lens.
  • Auto Montage, Photoshop CS4, Genuine Fractle 4, Helicon Focus 5 Pro.
  • Nikon SF-200 super coolscan 400ED

As a microscopist you often have to work with specimens that are difficult to focus. When viewing a 3-D specimen using an optical microscope you frequently cannot see the entire specimen in focus at any one time, due to depth of field limitations.

Your only option is to view a series of partially focused images. If it is critical to see the whole specimen in focus, then you may have to manipulate several images with computer software or draw it by hand, to produce the picture you are after.

Various software packages – Auto-Montage Pro, Helicon Focus 4.21 Pro, combine the in-focus sections of the source images to produce one perfectly focused montage image in seconds.

We have three optical microscope setups that allow the scientist to capture a series of images, montage and produce a measurable 3-D image of their specimen:

Leica MZ 16 stereo microscope with polarization and transmitted light base with the Spot Flex Digital Camera System including imaging software: Auto Montage, Photoshop CS, Genuine Fractle 4
Olympus BX50 Microscope with polarization, DIC, 100x UPlanFl oil, 40x UPlanFl, 20x UPlanFl, 10x UPlanFl with the Spot Flex Digital Camera System including imaging software: Auto Montage, Photoshop CS, Genuine Fractle 4

Canon D7 and Nikon D3X Micro Imaging System with Infinity Long Distance Microscope tube and Objectives (CF2, CF3, CF4, CF5, HDF2). ML-1000 illuminator, Micro Nikkor 105mm f/2.8D and 60mm f/2.8D lens, Canon EFS 18-200mm f/3.5-5.6 IS including imaging software: Photoshop CS4, Helicon Focus 5 Pro.


Mr Martin Pueschel , Scientific Illustrator
Sue Lindsay , Microscopy and Microanalysis Unit, Manager
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