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  • SXRTO Oscilloscopes Explained

    Pico Technology have launched their latest 5 GHz SXRTO Sampler Extended Real Time Oscilloscope, but what is SXRTO. Learn more about the benefits and cost savings compared to Real Time Oscilloscopes, RTO below.

    The real-time oscilloscope
    Real-time oscilloscopes (RTOs) are designed with a high enough sampling rate to capture a transient, non-repetitive signal with the instrument’s specified analogue bandwidth. According to Nyquist’s sampling theorem, for accurate capture and display of the signal the scope’s sampling rate must be at least twice the signal bandwidth. Typical high-bandwidth RTOs exceed this sampling rate by perhaps a factor of two, achieving up to four samples per cycle, or three samples in a minimum-width impulse.

    Equivalent-time sampling
    For signals close to or above the RTO’s Nyquist limit, many RTOs can switch to a mode called equivalent-time sampling (ETS). In this mode the scope collects as many samples as it can for each of many trigger events, each trigger contributing more and more samples and detail in a reconstructed waveform. Critical to alignment of these samples is a separate and precise measurement of time between each trigger and the next occurring sample clock.
    After a large number of trigger events the scope has enough samples to display the waveform with the desired time resolution. This is called the effective sampling resolution (the inverse of the effective sampling rate), which is many times higher than is possible in real-time (non-ETS) mode.
    As this technique relies on a random relationship between trigger events and the sampling clock, it is more correctly called random equivalent-time sampling (or sometimes random interleaved sampling, RIS). It can only be used for repetitive signals – those that vary little from one trigger event to the next.

    The sampler-extended real-time oscilloscope (SXRTO)
    The PicoScope 9404 SXRTO has a maximum effective sampling rate in ETS of 1 TS/s. This corresponds to a timing resolution of 1ps, 2000 times higher than its actual maximum sampling rate.
    The PicoScope 9404-05 SXRTO has an analogue bandwidth of 5 GHz. This means that it requires a sampling rate of at least 10 GS/s, but for an accurate reconstruction of wave shape, we need far higher than this. The PicoScope 9404 gives us 200 sample points in a single cycle at 5 GHz and 140 points in a minimum-width impulse.

    So is the SXRTO a sampling scope?
    All this talk of sampling rates and sampling modes may suggest that the SXRTO is a type of sampling scope, but this is not the case. The name sampling scope, by convention, refers to a different kind of instrument. A sampling scope uses a programmable delay generator to take samples at regular intervals after each trigger event. The technique is called sequential equivalent-time sampling and is the principle behind the PicoScope 9300 Series sampling scopes. These scopes can achieve very high effective sampling rates but have two main drawbacks: they cannot capture data before the trigger event, and they require a separate trigger signal – either from an external source or from a built-in clock-recovery module.
    We’ve compiled a table to show the differences between the types of scopes mentioned on this page. The example products are all compact, 4-channel, USB PicoScopes.

    *Higher-bandwidth real-time oscilloscopes are available from other manufacturers.
    **These functions are possible at low sampling rates, up to 1 MS/s.

    Click HERE for further information, application support, demo or quotation requests  please contact us on 01582 764334 or click  to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • New Rigol MSO8000 Series Oscilloscope Offers 2GHz Analogue Bandwidth and 7 Instruments in 1.

    The NEW Rigol Technologies MSO8000 Series of oscilloscopes combine best in class sampling (10 GSa/sec) and memory depth (500MPts) with a modern, flexible User Interface enabled by their new UltraVision II architecture and innovative Phoenix Chipset.

    Three models available from 600 MHz to 2GHz, each with 4 analogue channels, and MSO ready the 8000 Series brings innovative analysis and visualisation capabilities to embedded design, power analysis, serial decode, and RF applications. Analyse your critical signals with zone triggering, 7 instruments in 1, Enhanced FFTs, colour grading, and histograms and now with Real-time eye diagram and jitter analysis. All supported by high sample rate, deep memory, and full memory measurements. The NEW 8000 Series Oscilloscopes provide unprecedented value and innovation.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Full area topography and thickness of sub-micron films

    Precise, reliable, characterisation of thin film topography and thickness, and substrate topography.

    Thin transparent thin films are critical across a variety of markets and applications, including consumer electronics, semiconductors and optics. Precise monitoring and control of thin film processes is achieved by measuring top surface, thickness, and substrate surface characteristics – all of which are enabled by multiple thin film measurement and analysis technologies available on ZYGO's 3D optical profilers.

    In an ideal world, a surface metrology technology developed to measure submicron films will retain its performance for topography alone. This takes account of metrics, such as resolution and throughput and even the configuration flexibility. For microscope based technologies, this means that films analysis should not restrict the choice of objective or zoom.

    For thick films, the signals are well separated and can be easily distinguished between the top surface and the substrate. However, a transparent film will generally produce an additional signal from the substrate and therefore the surface and substrate signals merge and are no longer separable. But this sensitivity to films also gives the opportunity for the distorted CSI signal to be decoded to simultaneously determine surface and thickness.

    Fig1. Typical CSI signals for (a) bare surface (no film); (b) thick film (well over 1µm) with well-separated signals from surface to substrate; and (c) submicron film with merged surface and substrate signals.

    Advanced Model Based Analysis (MBA) is the most advanced CSI-based thin film measurement technique available from ZYGO, and works by comparing a theoretical model of the sample film stack to an actual measurement signal as seen by the profiler. This patented technology simultaneously measures topography, thickness, and substrate topography for single layer films from 50–2000nm in seconds. In addition to thin film characterisation, MBA technology can be used to perform true topography measurements of dissimilar materials by adjusting for the phase change on reflection (PCOR) that occurs in these situations.

    Standard Film Analysis (LSQ) is used to measure film thickness and substrates of films from 1–150µm optical thickness, as well as the top surface of films from 0.4–150µm. Thick film metrology works by isolating the interference signals that are created by the multiple material interfaces and require only basic knowledge of the film's index of refraction.

    Because they are based on CSI technology, there are several advantages that MBA and LSQ thin film measurement technologies provide compared to other techniques:

    • 3D areal surface maps provide context for understanding a process that cannot be observed when film metrology is reduced to a single thickness number.
    • Film measurement is performed through-the-lens, which helps to ensure that the region of interest is exactly the region profiled.
    • No additional hardware is required for most applications of MBA or LSQ thin film measurement.

    Standard Film Analysis (LSQ) is available as an option on NewView 9000, Nexview and Nexview NX2 profilers, while Advanced Model Based Analysis (MBA) is available as an option exclusively on the Nexview and Nexview NX2 platforms.

    To speak with a Sales & Applications Engineer please call 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • What is additive manufacturing technology? How does the process work?

    Additive manufacturing is a relatively new manufacturing approach that has attracted the attention of many people and industries around the world due to its unlimited and promising potential. In this blog we will describe what Additive Manufacturing (AM) technology is and how it works and in a follow-up blog we will explain how SEM analysis can assist in improving the quality of the AM processes.

    What is additive manufacturing?
    Additive manufacturing, also known as 3D printing or rapid prototyping, according to its ASTM standard is the “process of joining materials to make objects from 3D model data, usually layer upon layer, as opposed to subtractive manufacturing methodologies, such as traditional machining”. Today, the term “additive manufacturing” is mostly used in industry markets, while 3D printing mostly refers to the consumer market.

    Benefits of additive manufacturing technology
    Look again at the definition of AM by the ASTM standards and you’ll see its major benefit has already been revealed. Conventional subtractive manufacturing uses processes that withdraw materials from a larger piece to form the final 3D object, while AM processes add materials only when needed.

    The latter, combined with material reutilisation, reduces the material waste involved in the creation of a 3D object, lowering its environmental footprint.

    The other major advantage of AM compared to conventional manufacturing processes that have been used until now is the design freedom that it brings. In principle, everything that is designed with CAD products can be produced with additive manufacturing.

    That of course enables customisation, providing designers with the opportunity to offer specific solutions for every application. AM also enables a more extensive variety of highly complex structures to be created. It opens up new opportunities to innovate by adding new designs, or changing and/or revising versions of a product in a way that was not possible before. For example, new, more light-weight structures are being created to substitute bulkier products since AM allows parts to be designed with material present only where it needs to be. An example of this can be seen in Fig 1.

    Fig 1: Titanium 3D-printed limbs, designed by William Root.

    Moreover, AM offers shorter production cycles, requires no special manufacturing tools other than the AM machine, and reduces labor time and (energy) costs.

    Limitations of additive manufacturing technology

    Of course, AM also has its limitations, mainly because it's still under development and therefore evolving. First of all, until now, AM did not seem relevant for mass production and showed certain limitations regarding scaling, material size and choice.

    It has also been shown that in certain cases, post-processing of products is required to realise the correct surface finish and dimensional accuracy.

    However, AM has captured the interest of many people and industries that are constantly working on finding solutions to these limitations and improving the process and the quality of the products designed using it.

    Another factor that has had a negative effect on the rise of AM, is the potential loss of jobs in manufacturing. Of course, this is always the case with new technologies and hopefully people will adapt and develop the new skills that are essential for the new jobs that it will create.

    Additive Manufacturing: Areas of application
    Because of its great potential, AM has shown to be beneficial for a large variety of applications. In some areas, AM products are currently used in low-volume productions while in other areas, research is still going on to optimise the processes.

    As a first step, additive manufacturing can be applied to producing models and prototypes during the development stage of a product, and later on, as a production of pilot series for specific applications up to low-volume production for certain products.

    As a first application field, researchers are applying additive manufacturing processes for medical and dental applications. These include medical and surgical implants, prosthetics, bio-manufactured parts, and even pills.

    It is evident that the main advantage of AM for such applications is its versatility and customisation possibilities, allowing for tailored solutions within every use case.

    Up to now, several AM designs are currently used in automotive (e.g. motor parts and cooling ducts), aerospace (e.g. turbine blades and fuel system parts) and in tooling. You can see examples of these products in Fig 2.

    Fig 2: Examples of AM products in a) Aerospace, b) Automotive and c) Medical applications.

    Of course, there are many more applications in which 3D printing has been applied and/or will be applied in the future. Designs are currently used in education and research, construction, art and jewellery, sensors, and even apparel and clothing.

    Obviously, as more people get involved in the research and development as well as quality control of AM products, new application areas will pop-up and AM processes will become common practice for a variety of applications and products.

    Additive Manufacturing & SEM

    As with every emerging technology, quality control of the entire process is an important task. Material characterisation (e.g. particles) and quality control of the finished product — and everything in between —are all essential -to ensure the quality of the manufacturing process.

    In a follow-up blog, we will describe how scanning electron microscopy (SEM) is a powerful tool for material characterisation and quality control in additive manufacturing processes.

    Until then, we'd like to point you to an interesting video on exactly that topic. It explains how Additive Industries, the world’s first dedicated equipment manufacturer for industrial metal additive manufacturing systems, uses SEM to obtain fast results in additive manufacturing.

    Topics: 3D Printing, Materials Science, R&D, Additive Manufacturing

    About the author:
    Antonis Nanakoudis is Application Engineer at Thermo Fisher Scientific, the world leader in serving science. Antonis is extremely motivated by the capabilities of the Phenom desktop SEM on various applications and is constantly looking to explore the opportunities that it offers for innovative characterisation methods.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • OptoTest equipment provides the most accurate Return Loss measurements in the industry.

    In this presentation you will learn more about the techniques making that possible, plus some useful tips to keep in mind to ensure optimal performance.

    Click here to download the full presentation.

     

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Nikon Metrology NV and Pixelink Announce New Strategic Partnership

    Delivering a Selection of High Quality Industrial Microscopy Cameras to Fulfil the Needs of Mid-range Customer Requirements

    Nikon Metrology NV, innovator in measuring and precision instruments, and Pixelink, leader in design and manufacturer of high quality industrial cameras. Today, the two companies announced they are entering into a strategic partnership to accelerate sales of affordable industrial microscopy cameras in Europe. As part of this collaboration, Nikon Metrology NV will distribute Pixelink cameras as stand-alone solutions or integrated with Nikon NIS-Elements Microscope Imaging Software.

    Pixelink industrial microscopy cameras, featuring USB 3.0 connectivity, the latest high-resolution CMOS sensors, and global or rolling shutter technology, offer high quality image acquisition and maximum performance. The M-Series high definition cameras offer rapid refresh rates, crisp live images, fluid navigation, and fast focusing. Available from 4MP to 15MP resolution, the cameras perfectly complement Nikon Metrology NV products and are ideal for use in a wide range of industrial/material science applications.

    Nikon Metrology is very excited about this new partnership with Pixelink,” comments Bill Clement, Business Development Director, Nikon Metrology. “The selected Pixelink M-series camera models will greatly complement our camera offerings by providing each of our customers an optimal industrial microscopy solution to meet their application needs at an affordable price.

    The strategic partnership with Nikon Metrology NV is indeed very exciting. These cameras are fully integrated with Nikon NIS software and can easily be used in conjunction with Nikon’s state-of-the-art vision measuring instruments,” adds Lisanne Glavin, General Manager at Pixelink.

    Camera models now available through Nikon Metrology NV include the M5DC Versatile, M12BC Fast 4K, M4C Measurement and the M15C Documentation. All cameras come in a rugged cylindrical housing bundled with a 2M industrial USB 3.0 cable and Pixelink Capture image acquisition software.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • How to Save Time When Testing Multiple Cable Types

    Changing out reference cables during the insertion loss and return loss testing process to accommodate new DUT types can cause downtime for a manufacturing line and drastically reduce the efficiency of the cable production process.

    With single channel DUTs and reference cables, the issue may seem inconsequential. However, in the modern fibre production line every minute counts; any method that can speed up time per test, minimise the time between tests, and prevent downtime are ways to make your cables more profitable.

    Figure 1: An OP940 insertion and return loss meter with multiple reference cables: MTP, LC Duplex, SC, and FC connectors.

    One way to minimise this downtime is to connect multiple different reference cables to your multi-channel insertion loss and return loss test set in advance.

    Having reference cables that match the different connector types you commonly test or that will be tested that day at that test station will minimise the time it takes to start testing new DUT types.

    Additionally, it allows connector-level insertion loss testing for many types of hybrid cables without a complicated test setup if you have a reference cable that matches each.

    Ideally, the setup includes enough channels to accommodate the different reference cable types at once, as shown in Figure 1. Discuss with your sales engineer your testing needs and they can recommend an ideal test setup and channel count.

    Figure 2: Connector end-faces before (top) and after (bottom) cleaning.

    Finally, having reference cables that are only disconnected from time to time means that you have more repeatable IL/RL results and you can prevent damage to high quality reference cables and the interfaces to the test equipment.

    This will reduce overall downtime and cost associated with troubleshooting and repairing the damage to those connections.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • How a microfabrication researcher uses SEM as a technique to verify nanoscale structures

    Microfabrication, the creation of microscale structures and features, is an essential technique for the creation of next-generation semiconductors, processors and the ‘lab-on-a-chip’ microfluidic systems found in chemical analysis systems that can fit in the palm of your hand.

    Until now, microfabrication has relied on masking techniques such as lithography, which limits the variety of structures that can be produced. However, new research into microscale 3D printing systems is allowing complex 3D shapes to be assembled at scales smaller than ever achieved before.

    The future beckons

    Tommaso Baldacchini is a microfabrication researcher for the Technology and Applications Center (TAC) at Newport Corporation. In his research into laser-assisted nanofabrication, a Phenom Pro scanning electron microscope is an essential tool.

    Newport Corporation’s TAC labs are very similar to those that you would see at a University, and they closely cooperate with academic customers. TAC conducts experiments for academic partners and fabricates micro-devices and components for use in other academic research areas.

    The current microfabrication landscape

    Up to the current time, much microfabrication has been dominated by traditional machining and photolithographic processes, which are planar techniques. According to Tommaso Baldacchini, photolithography can produce an extremely fine structure with high throughput, but the process is limited by two-dimensionality. Baldacchini said “this means that fabricators are missing out on one entire dimension.” Other limitations include:

    • The expense of the instrumentation for producing these structures
    • A clean room environment is often required
    • The number of substrates and materials is limited to silicon and semiconductors

    Baldacchini mentions: “There is definitely a need to break the barriers of these limitations to produce new micro and nano devices.”

    Breaking down barriers to nanofabrication

    A number of challenges are presented when fabricating nanostructures. These depend mostly on the specific technique used to fabricate the structure and the features of the structure itself — such as its size, shape and surface area.

    Laser assisted nanofabrication (Journal of Laser Applications 24, 042007 (2012)) provides a whole raft of unique abilities for building nano- and microstructures. Laser irradiation projected on material surfaces can cause several effects, including localised heating, melting, ablation, decomposition and photochemical reaction — and leads to the realisation of various complex nanostructures with materials such as graphene, carbon nanotubes and even polymers and ceramics.

    Characterisation

    When characterising structures, it is crucial to have a tool that allows precise measurements to examine fabricated structures at nanoscale precision. There is a need to look at the structures topology and uniformity to make sure the ‘build’ quality is up to scratch. It is also important to be able to characterise the new material by determining its surface composition, and even its internal composition.

    A scanning electron microscope (SEM) is the ideal tool for this type of work, providing the ability to focus in to tens of thousands of nanometers and view small scale and nanoscale sample features. Baldacchini said “A scanning electron microscope is an invaluable tool to characterise products. We can view changes in the samples surface when it is ablated, or we can use SEM to study the topology of a sample we have produced using additive manufacturing.”

    Innovative techniques

    TAC have developed a high-resolution, nanoscale 3D printing technique called two-photon polymerisation. Using two-photon polymerisation allows the creation of extremely 3D polymeric structures which are often tens of microns large with nanoscale features. SEM is frequently used for structure characterisation, as a means of verifying the nanoscale structure that has been built. In addition to this, Baldacchini’s research has involved applying nonlinear optical microscopy, such as CARS microscopy, to investigate the chemical and mechanical properties of the microstructure created by two-photon polymerisation.

    “One of the tools that we developed in the TAC for aiding laser microfabrication is called the Laser µFAB. It is a complete system that enables customers to connect their own laser to the machine and perform different types of laser micromachining.”

    The system is provided with software that enables customers to import a two-dimensional drawing and reproduce the drawing using the motion of the stages with respect to the stationary laser. This allows users to create any three-dimensional objects they want to produce.

    Characterisation with a SEM

    So, according to Baldacchini at Newport Corporation, a scanning electron microscope proves to be an invaluable tool to characterise products and verify nanoscale structures.

    If you would like to learn even more about how TAC utilises SEM to verify nanoscale structures, you can click here to download the detailed Case Study.

    Topics: 3D Printing, Electronics

    About the author:
    Jake Wilkinson is an editor for AZoNetwork, a collection of online science publishing platforms. Jake spends his time writing and interviewing experts on a broad range of topics covering materials science, nanoscience, optics, and clean technology.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • FEG vs. Tungsten source in a scanning electron microscope (SEM): what’s the difference?

    After few years of operating a transmission electron microscope (TEM) in my postgraduate studies, in 2006 I started my career in electron microscopy as an SEM operator for a biological and medical research centre in York (United Kingdom). Not knowing how to operate an SEM before, I found it relatively easy to switch from TEM to SEM.

    My first SEM—equipped with a tungsten source—was getting too old and difficult to maintain. For that reason, it was replaced by two brand new SEMs; the first equipped with a tungsten source and the second with a Field Emission Gun (FEG). The tungsten system was considered the ‘workhorse’, and was used by many co-workers and researchers.

    However, challenging specimens (such as nanoparticles and beam-sensitive specimens)could be difficult to image on a tungsten system due to the lack of resolution. Whereas with the FEG source, those difficult specimens were much easier to image. The FEG system allowed us to see things that we couldn’t resolve with a tungsten system. It was like exploring and discovering a completely new world. Ever since that day, I’ve been in love with the FEG source.

    In this blog, I would like to make you enthusiastic too and explain why I prefer using an FEG source in an SEM system. You can learn what the main differences are between a tungsten thermionic emitter and a field emission source, and find out how an FEG source could enhance your research.

    Thermionic emission sources vs. field emission sources

    • Thermionic emission sources (TEM)
      Typically, thermionic filaments are made of tungsten (W) in the form of a v-shaped wire. They are resistively heated to release electrons (hence the term thermionic) as they overcome the minimum energy needed to escape the material.
    • Field emission sources
      For a field emission source, a fine, sharp, single crystal tungsten tip is employed. An FEG emitter gives a more coherent beam and its brightness is much higher than the tungsten filament. Electrons are emitted from a smaller area of the FEG source, giving a source size of a few nanometers, compared to around 50 μm for the tungsten filament. This leads to greatly improved image quality with the FEG source. In addition, the lifetime of an FEG source is considerably longer than for a tungsten filament (roughly 10,000 hours vs 100-500 hours), although a better vacuum is required for the FEG, 10-8 Pa (10-10 torr), compared with 10-3 Pa (10-5 torr) for tungsten, as shown in Figure 1.

    There are two types of FEG sources: Cold and Schottky FEGs

    For a so-called cold emission source, heating of the filament is not required as it operates at room temperature. However, this type of filament is prone to contamination and requires more stringent vacuum conditions (10-8 Pa, 10-10 torr). Regular and rapid heating (‘flashing’) is required in order to remove contamination. The spread of electron energies is very small for a cold field emitter (0.3 eV) and the source size is around 5 nm.

    Other field emission sources, known as thermal and Schottky sources, operate with lower field strengths. The Schottky source is also heated and dispenses zirconium dioxide onto the tungsten tip to further lower its work function. The Schottky source is slightly larger, 20–30 nm, with a small energy spread (about 1 eV).

    It starts with sample preparation

    When switching from tungsten to FEG emitter, it is worth mentioning that the specimen preparation becomes extremely critical in order to obtain high resolution and high magnification of any specimen.

    In general, samples are generally mounted rigidly on a specimen holder or stub using a carbon ‘conductive’ adhesive. These carbon tabs are partially or non-conductive and can lead to charging artefacts. Hence, carbon tabs might be suitable for a tungsten system, but become inappropriate for an FEG system.

    For high-resolution imaging on an FEG system, I always try to avoid using the carbon sticker. Specimens such as nanoparticles or fine powder should be prepared directly onto an aluminum pin stub for example.

    For conventional imaging in the SEM, specimens must be electrically conductive, at least at the surface, and electrically grounded to prevent the accumulation of electrostatic charge (i.e. using silver paint, aluminum or copper tape). [copper tape?]

    Non-conducting materials are usually coated with an ultra-thin coating of electrically conducting material, including gold, gold/palladium alloy, platinum, platinum/palladium, iridium, tungsten, and chromium. I recommend using the metals and thickness below for tungsten and FEG sources:

    • Metals:
      Au, Au/Pd (Tungsten source)
      Pt, Pd/Pt, Ir, W (FEG source)
    • Thickness:
      5-10 nm for low magnification
      2-3 nm for high resolution, the thinner the better

    Tungsten source vs. FEG source: imaging differences

    FEG sources have an electron beam that is smaller in diameter, more coherent and with up to three orders of magnitude greater current density or brightness than could ever be achieved with a tungsten source.

    The result of using an FEG source in scanning electron microscopy (SEM) is a significantly improved signal-to-noise ratio and spatial resolution, compared with thermionic devices.

    Field emission sources are ideal for high resolution and low-voltage imaging in SEM. Therefore, focusing and working at higher magnification become easy for any operator.

    Topics: FEG

    About the author:
    Kay Mam - In 2006 I started my career in electron microscopy as an SEM operator for a biological and medical research center in York (United Kingdom). With an FEG source, difficult specimens are easier to image. The FEG system allowed me to see things, it was like exploring and discovering a completely new world. Ever since that day, I’ve been in love with the FEG source. In 2016, I joined the Phenom Desktop SEM Application Team, working on a desktop SEM with an FEG source.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

  • Micro-Spectroscopy Seminar - Dublin

    Attend our FREE seminar to learn more about Infra-Red,
    Raman and Electron Microscopy.

    Wednesday, June 12th, 2019
    09:00 –16:00

    Carlton Hotel Blanchardstown
    Church Rd, Tyrrelstown
    Dublin 15

    • Learn how the combination of FTIR and/or Raman microscopy and SEM can provide a holistic insight into a materials’ structure-function relationship from both the chemical and the morphological standpoints.
    • Speak with the experts to help understand challenging applications
    • Get the latest information on Applications such as Micro-Plastics, Battery Technology, Composites, Pharmaceuticals and many more.

    CLICK HERE for more event information and registration details.

    For further information, application support, demo or quotation requests  please contact us on 01582 764334 or click here to email.

    Lambda Photometrics is a leading UK Distributor of Characterisation, Measurement and Analysis solutions with particular expertise in Electronic/Scientific and Analytical Instrumentation, Laser and Light based products, Optics, Electro-optic Testing, Spectroscopy, Machine Vision, Optical Metrology, Fibre Optics and Microscopy.

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