Sample Preparation Laboratory
Sample Preparation Facilities
The nmRC has a fully equipped sample preparation laboratory to support its electron microscopy and chemical analysis facilities. In order for samples to be analysed by SEM, TEM, XPS and Raman Spectroscopy there are a variable number of requirements for sample pre-processing.
The preparation lab at the nmRC is therefore outfitted with a spectrum of preparation instrumentation designed to support the breadth of specialist sample analyses the centre is tasked with performing and enable them to be run according to the specialism required. Catering for students (and customers) from disciplines including life sciences, chemistry, physics, pharmacy, chemical engineering, advanced materials, archeology etc. the nmRC uses a variety of supporting infrastructure to underpin its core services.
The sample preparation lab is equipped with two high flow fume hoods, hot plates, balances, ultrasonic baths and a general vacuum oven. Larger equipment is listed below:
nmRC Sample Preparation Instrumentation
Gatan Cryo-Plunge 3
The Cryoplunge 3 is a semi-automatic plunge freeze instrument for the preparation of frozen hydrated specimens for cryo transmission electron microscopy (cryoEM).
Fischione Plasma Cleaner
The Model 1020 Plasma Cleaner automatically and quickly removes organic contamination (hydrocarbons) from electron microscopy (EM) specimens and specimen holders. A low energy, reactive gas plasma cleans without changing the specimen's elemental composition or structural characteristics. The Model 1020 features easy-to-use front panel controls and an oil-free vacuum system for optimal processing.
Fischione Model 1010 Low Angle Argon Ion Beam Miller and Polisher
Conventional Argon ion beam milling. The ion sources operate over user-selectable ranges of voltage (0.5kV to 6.0kV) and current (3mA to 8mA), and are capable of producing ion beam currents up to 400 microamps. Selectable milling angles are from 0 to 45°. Liquid nitrogen cooling during thinning and temperature control options are available. The system is computer controlled, allowing saving and reloading of milling parameters and logging of milling process.
RMC Products PowerTome and CR-X Cryo Ultramicrotome
For production of TEM suitable slices from samples, at room and liquid nitrogen temperatures. The microtome design reduces "play" between the parts of the engine to a minimum, virtually eliminating section chatter and susceptibility to external vibration. The powered cutting stroke has enough strength to cut through even hard, non-homogenous specimens. The CR-X Cryosectioning system attachment features "through the wall" arm, vibrationless LN2 delivery, and four temperature presets.
Agar Turbo Carbon Coater and Sputter Coater
The coater uses a feedback controlled Bradley-style rod source to give efficient and reproducible carbon evaporation with predictable spatial distribution and uniform thickness. It can be used in automatic or manual modes. The high pumping speed of the integrated vacuum system gives very short coating cycle times. The coater is fitted with a film thickness monitor system.
Leica EM CPD300 Critical Point Dryer
The critical point dryer (CPD) is used to dry biological specimens such as pollen, tissue, plants, insects, etc. as well as industrial samples, in a fully automated and controlled process while retaining their hydrated structure. The procedure of critical point drying utilises that fact that at the critical point of a material the physical characteristics of a liquid and gas are not distinguishable. Compounds which are at the critical point can be converted into the liquid or gaseous phase without crossing the interfaces between liquid and gas therefore avoiding the damaging effects. The critical point of water is too high for use, so water is exchanged in the sample using ethanol (or acetone) before this is in turn replaced with liquid CO2. The critical point of CO2 is sufficiently low to enable an efficient dehydration while preserving fine structure.
Quorum and Polaron Iridium, Gold and Platinum Sputter Coaters
For high resolution imaging on a SEM, gold and platinum coats produce significantly better results. An argon plasma is used in a vacuum chamber to sputter particles of metal from the targets which form a thin (<15 nm) layer on the sample. Iridium is the finest grading of coating and is recommended for FEG-SEM work, gold is recommended for heat sensitive samples (such as biological specimens) and platinum for all other high resolution work.
Dimplers are used as an initial step in TEM preparation of solid samples, before ion milling. These machines thin solid samples down to a few microns before the ion miller thins to electron transparency. 3 mm diameter samples are needed for these machines.
Ultrasonic Disk Cutter
Ultrasonic disk cutters are used to produce 3 mm diameter samples for the dimplers. They can produce these from brittle materials which would otherwise fracture in the production.