Characterisation, Measurement & Analysis
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Press Releases

Lambda's press releases

  • Phenom Pharos Wins Analytical Scientist Innovation Award!

    The Thermo Scientific™ Phenom Pharos Desktop SEM has been voted second place in the Analytical Scientist Innovation Awards 2018! The microscope – which was introduced in August 2018 – is the flagship of the Phenom Desktop SEM product range.

    The Phenom Pharos is the first desktop SEM solution from us that includes a field emission gun (FEG). It is easy to operate and incorporates an advanced hardware design for fast time-to-image and simple handling. A wide range of academic and industrial researchers now have access to the benefits of FEG in a desktop model, which can increase their throughput and result in high-quality images and resolution.

    In addition to providing advanced detectors that can acquire high-quality images with magnifications up to 1,000,000 times, the Phenom Pharos microscope offers researchers:

    • Access to sharp, high-contrast images with resolutions <3 nanometers
    • An intuitive user interface that enables researchers to get a live image in less than 25 seconds after inserting the sample
    • High-resolution imaging that can be obtained simultaneously with analytical techniques

    Potential impact

    In the past, only highly-experienced scientists have been able to operate and benefit from FEG- equipped scanning electron microscopes (SEM), but Phenom Pharos brings the benefits of FEG to users with different experience levels; it is easy to use, and installation can be done without the need for special room requirements. Installation is fully automated and once initialised, the user interface enables researchers, students and operators alike to analyze images and corresponding details at the nanoscale, from visualising multiwall carbon nanotubes to capturing high-resolution imaging of Ag nanoparticles.

    Learn more about the Phenom Pharos  

    For more information please email or call 01582 764334.

    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.

  • Baumer wins the inspect award 2019 with its CX.I cameras

    The Baumer CX.I cameras with their outstanding performance convinced the expert panel and participants of the online poll on the inspect award 2019 and were awarded 1st prize in the Vision category. The prize that is annually awarded by Wiley-VCH publishers recognises special innovation in the area of industrial image processing. An expert panel selects the best 10 products each in the categories Vision, Automation and Control. From these, more than 45000 readers of the magazines inspect and messtec drives Automation as well as from other online portals were asked to select their favourite in an online voting process.

    The Baumer CX.I cameras gained headway with their overall concept that offers increased performance. For example, thanks to an expanded operating temperature range of -40°C to 70°C, no additional cooling or heating devices are necessary, which allows rapid and cost-effective system integration. 4 power outputs with pulse width modulation and an output power of up to 120W (max. 48V / 2.5A) allow direct lighting control and make additional components unnecessary. With exposure times from 1µs and frame rates of up to 1000 fps, the cameras can be deployed across industries flexibly and in demanding applications. The patented modular tube system allows lenses of different lengths to be protected against dust and dirt rapidly and flexibly using a variable number of extension rings. And when the demands are even greater, specially developed IP 65/67 and IP 69K housing accessories transform the CX.I cameras to IP 65/67 or IP 69K cameras in no time at all for use in hygienic areas of the food, beverage and pharmaceutical industries.

    Why not give us a call now on 01582 764334 if you would like a free trial of the camera or click here to email.

    Further information on our Machine Vision camera series click here.

    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.


  • Why SEM is a valuable technique for nanoparticle characterisation

    The continuous increase of microscopic particles’ use in a huge range of applications has created the need of accurate control of their properties. I will explain why the use of precise monitoring and characterisation of particles is required and how scanning electron microscopy can prove to be a valuable characterisation method for you. Especially due to its versatility and superior spatial resolution.

    The term “particle” is quite a general term as it describes any discrete sub-portion of a substance. It can range from the subatomic scale with the study of particles (size of 10-15 m), to the microscopic range with atoms (0.3Å) and molecules (nm-μm), up to the macroscopic scale that can include particles of dust, dirt, skin (mm-cm) or even planets of a galaxy (~ 10−6m in the case of Earth). So, the understanding of a precise definition for “particles” is quite a difficult task. Therefore the common understanding is that particles can vary greatly in terms of size and shape.

    Microscopic particles: why are they so interesting?

    But let’s focus on one of the categories of particles as described above, the microscopic particles. This category of particles is exceptionally interesting since they are used in a huge range of applications, such as ceramics, the food industry, electronics, polymers and plastics, cosmetics and pharmaceuticals. It has been proven that the size and shape of such particles influence the properties of the materials.

    In principle, most of the materials are size dependent; the physical properties of materials at the nanoscale can differ from the constant physical properties of the same material existing in bulk form. There are several factors for this behaviour. First, as we move to nm dimensions, classical mechanics can no longer describe the processes and should be replaced by quantum mechanics. Moreover, the surface to volume ratio increases greatly, potentially affecting certain properties of the materials (Fig 1).

    Fig 1: Increased surface to volume ratio for materials comprised of particles compared to bulk.

    Nanomaterials with altered properties

    There are many examples of nanomaterials with altered properties compared to their bulk counterparts. For instance, the optical properties of gold are very different in bulk and in nanoscale. We all know that gold is yellow, however this is not true for gold nanoparticles. Their colour can vary from purple to red, depending on their size (Fig 2). Also, ZnO nanoparticles do not scatter visible light in contrast to their bulk counterparts, which are used for sunscreen creams.

    Fig 2: Change in the optical properties of gold as the size of its particles decreases.

    But it is not only the optical properties that alter, the electrical properties can also differ at the nanoscale. Some materials that act as conductors in bulk can become semiconductors and vice versa. So it becomes evident that the size of the particles is an important factor that can affect their properties in many diverse applications.

    For example, it can affect the delivery efficiency in medical applications, the reactivity and the dissolution rate in catalytic processes, their appearance when used as coatings and inks, and the porosity of the products in ceramics. Particles of such size are very appealing for medical applications as drug delivery agents due to their increased surface to volume ratio and their ability to absorb and carry several compounds.

    Besides size, the shape of the particles is also a decisive factor that can affect the properties of the materials and thus the product in which they are used. In a similar manner as size, shape can alter the texture and feel of food ingredients, the flowability and reactivity of agents used in medical or other applications. Furthermore, other particle characteristics, such as convexity and circularity, are important as they can also affect their properties.

    Obtaining images of particles

    Fig 3: Particle metric workspace. On top, the acquired SEM image is processed and the particles are identified. At the bottom, the results of the analysis are shown; size and shape distribution as well as important characteristics of the particles are shown.

    It is obvious that the tunability of these particles is fascinating and has gathered the focus of many research groups around the world due to their great potential in applications and their huge variety. In principle, the properties of materials can be finely tuned by engineering their size and shape. To achieve this, many characterisation techniques have been employed in order to obtain the so-called particle shape and size distribution.

    Obtaining images of particles comes along with challenges as usually a statistical outcome of the measurement would be ideal. For such purposes an automated analysis program such as Particle Metric (Fig 3) can help. It combines high-resolution electron imaging with an automated analysis and classification of particles in your image. This depends not only on their size and shape, but also many other characteristic such as the convexity, circularity, surface and volume of the particles.



    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.

  • SEM trends: what is next? Automated scanning electron microscopy

    Automated scanning electron microscopy (SEM) saves operators valuable time. Both in research and in industry this further development of SEM is in great demand and is a rapidly growing field. Thermo Fisher Scientific™ already offers innovative Phenom desktop SEM products and applications for automated imaging as well as analysis.

    In industry, automation is anything but a new phenomenon. Using automated systems enables companies to produce large quantities of products with simultaneous precise and rapid quality control. Although SEM technology is used in the manufacturing industry for microscopic analysis (for example for quality and failure control), automated SEM systems with a high and fast sample throughput are rarely available on the market. One of the main reasons for this is that SEM is technically very sophisticated. In addition, SEM has traditionally been primarily a technology for scientists and research purposes. For them, a high sample throughput is not as important as for manufacturers, for whom several hours or even minutes can have a big impact on the eventual profit.

    Advantages of automated SEM systems

    As mentioned above, the most obvious advantage of automated SEM systems is a much higher sample throughput. Automated SEMs are able to deliver a statistically-relevant characterisation of different samples within a shorter time frame. Moreover, only automated systems can literally find the ‘needle in the haystack’. This becomes relevant if the operator’s task is to find a specific feature on a sample within a large number of other features. In this case, automatic imaging and analysis offers a great advantage over human operators.

    Another advantage of using an automated system is that it eliminates human bias. Individual users direct their attention to problems in very different ways. Therefore, having different users examine the same problem makes comparing results difficult. Only automated systems can guarantee consistent results.

    As a consequence, virtually all SEM operators benefit from a faster, automated SEM imaging process and a subsequent automated image analysis. The good news is: new developments and advances in SEM are delivering automated solutions – and one can say with confidence that the future of SEM lies in automated systems.

    Thermo Scientific Phenom desktop SEM automated products

    As a company that is dedicated to delivering innovative and forward-thinking SEM solutions, Thermo Fisher Scientific has already started to offer automated approaches and applications. The Thermo Scientific Phenom XL is a desktop SEM that enables automated analysis of samples, while at the same time providing the fastest ventilation and evacuation cycle of any SEM available on the market. The entire process of venting the chamber, placing the sample and establishing the vacuum environment only takes approximately one minute. Moreover, the innovative sample holder can accommodate up to 36 small specimens on stubs or one single large object with a maximum size of 100 square centimetres. Thus, operators are able to quickly examine many samples or different spots within one large object.

    In order to analyse the imaging data, different automation scripts are provided. Users can apply these algorithms to automatically acquire, analyse and evaluate images. This can speed up the examination process enormously.

    In industry, these compact and semi-automated systems can, for instance, be positioned next to the production line and provide quality control and failure analysis in real-time. Such set-ups mark the first step towards a fully automated SEM analysis that complements round-the-clock production.

    Automated risk assessment: AsbestoMetric

    Another specific automated application that has been developed is the Thermo Scientific Phenom AsbestoMetric Software for the detection of asbestos fibres. Since asbestos is a hazardous material, standards exist that describe the procedures that must be followed for a correct assessment of risks. These instructions include the analysis of collected material with a SEM in order to detect the potential presence of microscopic asbestos fibres.

    In general, this is a complex and time-consuming process because, according to the guidelines, more than 100 images must be inspected. And in general, only highly experienced SEM operators are able to detect the fibres as they are tiny and produce barely any contrast. However, Thermo Fisher Scientific succeeded in shortening this process significantly by automating the repetitive tasks in their Phenom desktop SEMs. With this system, the operator only has to verify the outcome and certify the accuracy of the results instead of spending hours searching for very small fibres. Since the SEM required for this task is quite compact, it can also be used as a mobile set-up in a vehicle. Several construction companies are already doing so and by using AsbestoMetric, they can immediately determine if there is asbestos on site and assess the risk. For more information, have a look at our blog.

    These examples clearly show automated processes are already supporting SEM users today. In future, automation will be part of every state-of-the-art SEM. With the automated solutions that is has available, Phenom desktop SEMs are already one step ahead. And the developers of the company are working hard to keep it that way in the future.

    CLICK HERE  to download the Phenom AsbestoMetric Software datasheet.


    About the author:
    Willem van Zyl is Application Specialist at Thermo Fisher Scientific, the world leader in serving science. He is excited by analytical instruments that are accessible and user-friendly, and truly believes that a SEM image is worth a kazillion words.

    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.

  • Sofradir Electrophysics7215 “Electroviewer” Handheld IR Viewer to be Discontinued

    Sadly, after many decades of production Sofradir Electrophysics will be discontinuing the 7215 Electroviewer IR handheld viewer. Production of the intensifier tubes used in this design is being halted due to lack of global demand, and there is no alternative replacement. The 7215 has been a hugely popular product, especially in laser labs, and we thank all our customers for their purchases over the years.


    Units are still available until current stocks are exhausted, and we encourage you to contact us and arrange a last-chance buy to fulfil your short/medium term requirements. We expect availability until the end of Q1 2019. Each unit is supplied with a standard 1 year warranty and enough tubes have been stocked to cover all sales and service obligations.

    We do have high performance InGaAs SWIR cameras covering similar wavebands from UTC/Sensors Unlimited - click here. We would be happy to discuss these with you.

    For more information or to arrange a last-time-buy, please email or call 01582 764334.

    Lambda Photometrics Ltd


    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.

  • Dynamic Capability comes to (nearly) all new Zygo Verifire Interferometers

    DynaPhase® Dynamic Acquisition for Extreme Environments
    Confidence in metrology, no matter the conditions

    Fizeau Interferometry has become a trusted standard for precise metrology of optical components and systems. Traditionally, these instruments were required to be installed in lab environments, where conditions were carefully controlled, to ensure high precision measurements were not compromised. However, today a growing number of applications demand easy, cost-effective solutions for the use of interferometry in environments where metrology has been difficult or impossible in the past.

    Often, optical systems must be tested in locations that simulate their end-use environment. These environments can present challenges due to factors like large vibration and air turbulence, which can negatively affect or prevent the ability to acquire reliable optical measurements. Many of these challenges are addressed with less than optimal solutions, often suffering from drawbacks and issues related to usability, speed, reliability and precision.

    ZYGO's patented DynaPhase® data acquisition technology offers many differentiated benefits, without the limitations associated with alternative methods. Key attributes of DynaPhase include:

    • Highest vibration tolerance in a Fizeau interferometer, enabled by the ZYGO-manufactured high-power laser* and fast acquisition speeds
    • Patented in-situ calibration enables the highest precision, lowest measurement uncertainty measurements, and excellent correlation to temporal phase shifting interferometry (PSI)
    • Simple setup and calibration compared to alternative approaches
    • Cost-effective solution; available on nearly all ZYGO laser interferometers

    Comparison of Measurement Techniques Using an Identical Measurement Cavity

    DynaPhase offers the versatility and performance to address a wide range of challenging optical testing environments and applications, including:

    • Cryogenic and vacuum chamber testing
    • Telescope components and complex optical systems
    • Large tower, workstations and complex or unstable test stands

    DynaPhase is available on nearly all ZYGO laser interferometers. Features vary by model and enable users the flexibility to use capabilities that enhance efficiency in Production Mode, enable fast system alignment with LivePhase, or reveal temporal changes in data with Movie Mode.

    Get the most from your metrology investment with the unique capabilities and unmatched versatility of DynaPhase, now available on the entire interferometer line from ZYGO.
    Complete range of vibration tolerant metrology - check out ZYGO's patented QPSI vibration tolerant temporal phase shifting data acquisition enables metrology in the presence of common shop floor vibrations without the need for calibration.

    DynaPhase is inherent in the DynaFiz interferometer - and available as an optional extra software module on the new Verifire (1200 x 1200 pixel camera), Verifire HD and HDx systems. This means you can have DynaPhase capability on the entry level Verifire interferometer, which is pretty well specified to start with as it includes QPSI technology also.

    Click here to read further information on QPSI™ Technology Shrugs Off Vibration from Common Sources.

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

  • New Baumer LX Cameras now with integrated JPEG compression

    We are pleased to announce that we are now delivering an on-board image compression video camera, which is able to transmit high-quality images and reduce the data output in real-time.

    Baumer is supplementing the hugely popular LX series with 2, 4 and 25 megapixel cameras with integrated JPEG image compression and frame rates of up to 140 fps. With the GigE cameras, your savings are continual: from bandwidth through CPU load to storage space – this simplifies the system structure design and reduces integration costs.

    Why not give us a call now on 01582 764334 if you would like a free trial of the camera or click here to email.

    Further information on our Machine Vision camera series click here.

    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.

  • SEM automation guidelines for small script development: evaluation

    Scripts are small automated software tools that can help a scanning electron microscope (SEM) user work more efficiently In my previous two blogs, I wrote about image acquisition and analysis with the Phenom Programming Interface (PPI). In this blog I will explain how we can use the physical properties we obtained in the last blog in the evaluation step.

    SEM automation workflows

    Typically, SEM workflows always consist of the same steps, see Figure 1. The four steps that can be automated using PPI are:

    1. Image acquisition
    2. Analysis
    3. Evaluation
    4. Reporting

    In the image acquisition step (1), images are automatically made using PPI and the Phenom SEM (read this blog for more information on this step). In the analysis step (2), the physical properties are extracted from the image (see this blog) .The images are evaluated based on these physical properties in the evaluation step (3). The final automated step (4) is reporting the results back to the user.

    Figure 1: Scanning Electron Microscopy workflow

    Image evaluation

    In the evaluation step, the physical quantities are evaluated and categorized. This can be done by:

    • Counting particles based on their morphology
    • Determining the coverage on a sample
    • Base actions on physical properties of the sample

    In this blog we will base action on the physical properties in an image to determine where the center of the copper aluminum stub is.

    To do this we will assume that the copper insert is perfectly round. The script will start at a location pstart within the copper part of the stub. From here it will move in both positive and negative x and y directions to find a set of four edges points of the copper insert. These points will be Schermafbeelding 2018-07-05 om 12.17.40. Because of the circular symmetry of the stub, the arithmetic average of the x positions of Schermafbeelding 2018-07-05 om 12.20.01 and the y-position of Schermafbeelding 2018-07-05 om 12.20.45 will yield the center Schermafbeelding 2018-07-05 om 12.21.08 of the stub. In Figure 2 all the points are shown.


    Figure 2: Definitions of the locations on the stub

    To find the edges, the stage is moved. In every step the image is segmented using the techniques explained in the previous blog. When less than 50% of the image consists of the copper part, the edge is located. The exact position of the edge point is then defined as the center of mass of the area that is neither copper nor aluminum.

    Figure 3: Definitions of the locations on the stub

    Code snippet 1 shows an example of how this can be done. First the stage is brought to its original starting point with the Phenom.MoveTo method. This position is retrieved back from the Phenom using the phenom. GetStageModeAndPosition command. After that, the step size is defined. A step of 250 µm is chosen, which is equal to half the image field width. Four vectors are defined in all directions to find the four edges. These vectors are combined into an iterable list, to be able to iterate over them in the for loop.

    In the for loop, the stage is first moved to an initial guess of the location of the center. Then, a while loop is started where the stage moves to one direction with the step size. At every step the image is segmented and checked if the area of copper is smaller than 50%. If the copper area is less than 50%, the edge has been found and the center location of the edge is determined using ndimage.measurements.center_of_mass method.

    The resulting center of mass is expressed in pixels and is converted to metric units using the metadata that is available in the Phenom acquisition objects. The centers of masses are stored in a list and from this list the Schermafbeelding 2018-07-05 om 13.09.38 and Schermafbeelding 2018-07-05 om 13.10.07 locations are determined. From the set of locations, the arithmetic averages are easily determined, and the stage is moved to its new improved center location.

    Code snippet 1: Code to find and to move to the center of the stub

    In Figure 4, the initial guess of the location of the center is shown on the left-hand side and the improved center location is shown on the right-hand side. Iterating this process a few times could improve the center location even further; this because the symmetry will improve towards the center of the stub.

    Figure 4: Definitions of the locations on the stub


    In code snippet 2, the complete code is shown, including the code from my two previous blogs.

    Code snippet 2: Complete code

    Click here to learn more about SEM automation and the Phenom Programming Interface

    Topics: Scanning Electron Microscope Automation, Industrial Manufacturing, Automation, PPI, Automated SEM Workflows

    About the author:

    Wouter Arts is Application Software Engineer at Thermo Fisher Scientific, the world leader in serving science. He is interested in finding new smart methods to convert images to physical properties using the Phenom desktop SEM. In addition, he develops scripts to help companies in using the Phenom desktop SEM for automated processes.

  • Buying a scanning electron microscope: how to select the right SEM

    You want to buy a new scanning electron microscope (SEM) because you know you need more SEM capability. Maybe you have a traditional floor model SEM, but it is slow and complicated to operate. Maybe you are using an outside service and the turn-around time is unacceptably long.

    You have made your case that your company could significantly improve their business performance and you could do your job better if SEM imaging and analysis were easier, faster and more accessible. Can a desktop SEM do what you need? This article provides the answers and helps you to select the right SEM.

    Floor model SEM vs. Desktop SEM

    The choice between a desktop SEM and a larger, floor model system is almost always primarily an economic one: desktops are much less expensive. But there are other factors that also argue in favor of a desktop solution, even when cost is not the primary consideration.

    Scanning electron microscopes: pricing & affordability

    Let’s deal first with SEM pricing. Desktop SEMs are typically priced at a fraction of their floor model relatives. And there are certainly situations in which the additional cost of the larger systems are justifiable, for example, when the resolution requirements are beyond those achievable in a desktop SEM system.

    However, today’s desktop SEM’s can deliver resolutions smaller than 10 nm, enough for 80%-90% of all SEM applications. So your first question has to be, is it enough for yours?

    Beyond the initial acquisition, there are significant additional costs for a floor model scanning electron microscope system:

    • facilities – typically at least a dedicated room (perhaps including specialized foundations and environmental isolation)
    • additional space and equipment for sample preparation; personnel – a dedicated operator, trained in instrument operation and sample preparation.

    It is worth noting that while the cost of the equipment and facility are primarily fixed costs of acquisition, the operator is an ongoing expense that will persist for the lifetime of the instrument.

    Clearly, a desktop SEM solution — less costly to acquire and with no requirement for a dedicated facility or operator — is the less expensive choice, as long as its capabilities satisfy the requirements of the application.

    Other decision factors when selecting and buying a scanning electron microscope

    • Microscope speed
      Desktop SEM systems require minimal sample preparation and their relaxed vacuum requirements and small evacuated volume allow the system to present an image much more quickly than a typical floor model system.Moreover, desktop SEMs are usually operated by the consumer of the information, eliminating the time required a dedicated operator to perform the analysis, prepare a report and communicate the result.In addition to faster answers, there is considerable intangible value in the immediacy of the analysis and the user’s ability to direct the investigation in real-time response to observations.Finally, in some applications, such as inspection, longer delays carry a tangible cost by putting more work-in-progress at risk.
    • Microscope applications
      Is the application routine well defined? If it is, and a desktop SEM can provide the required information, why spend more? Concerns about future requirements exceeding the desktop capability should be evaluated in terms of the certainty and timing of the potential requirements and the availability of outside resources for more demanding applications.Even in cases where future requirements will exceed desktop capability, the initial investment in a desktop SEM can continue to deliver a return as that system is used to supplement a future floor model system.Perhaps in a screening capacity or to continue to perform routine analyses while the floor model system is applied to more demanding applications.A desktop system may also serve as a step-wise approach to the justification of a larger system, establishing the value of SEM while allowing an experience-based evaluation of the need and cost of more advanced capability from an outside provider.
    • Microscope users
      How many individuals will be using the system? Are the users trained? If not, how much time are they willing to invest in training? Desktop SEMs are simple to operate and require little or no sample preparation. Obtaining an image can be as easy as pushing a couple of buttons.More advanced procedures can be accessed by users with specific needs who are willing to invest a little time in training. In general, the requirements for operator training are much lower with a desktop system and the system itself is much more robust. It is harder to break, and the potential repair cost is much lower.

    Buying a scanning electron microscope: take-aways

    Now a short recap. The primary decision factors when selecting a SEM are:

    • Pricing
    • Speed
    • Applications
    • Users

    The question to ask yourself while going over these factors is: does a desktop SEM meet my application requirements?

    From experience we can say that it will, in most scenarios. If a desktop SEM is indeed suitable for your application, you’re looking at an investment that’s significantly lower compared to a floor model SEM.

    Remember, desktop systems are typically priced at a fraction of their floor model relatives.

    As I stated earlier there are situations in which the additional cost of larger systems is justifiable. This is the case when the resolution requirements are beyond those achievable in a desktop system.

    However, today’s desktop SEMs can deliver resolutions less than 10 nm — enough for 80%-90% of all SEM applications. So the question will often be: is it enough for yours?

    If that’s a difficult question to answer — or if you’re still just in doubt which SEM to choose — we have an e-guide available that should be of help: how to choose a SEM.

    This guide takes an even deeper dive into the selection process of a SEM, and will help you select the right model for your process and applications.

    Topics: Research Productivity, Scanning Electron Microscope, Pricing

    About the author:

    Karl Kersten is head of the Application team at Thermo Fisher Scientific, the world leader in serving science. He is passionate about the Thermo Fisher Scientific product and likes converting customer requirements into product or feature specifications so customers can achieve their goals.

  • Sputter coating for SEM: how this sample preparation technique assists your imaging

    Scanning electron microscopes (SEMs) are very versatile tools that can provide information at the nanoscale of many different samples - with little or no sample preparation. In some cases though, sputter coating the samples prior to working with SEMs is recommended, or even necessary, in order to get a good SEM image. In this blog, we will explain how the sputter coating process works, and to which type of samples it should be applied.

    How does sputter coating work?

    As mentioned above, SEMs can image almost all kind of samples; ceramics, metals and alloys, semiconductors, polymers, biological samples and many more. However, certain types of samples are more challenging and require an extra step in sample preparation to enable the user to gather high-quality information from a SEM. This extra step involves coating your sample with an additional thin layer (~10 nm) of a conductive material, such as gold, silver, platinum or chromium etc.

    When a metallic target material is bombarded with heavy particles, the erosion of this material begins. Sputtering occurs when the erosion process takes place in conditions of glow discharge between an anode and a cathode. In this way, and by careful selection of the ionization gas and the target material, an additional thin layer (¬ 10nm) of a conductive material, such as gold, silver, platinum or palladium will coat your sample.

    Challenging samples that require sputter coating:

    • Beam-sensitive samples
      The first type of samples that are usually sputter-coated prior to loading in the SEM are the beam-sensitive samples. These are mainly biological samples, but they can also be other types, such as materials made from plastics. The electron beam in a SEM is highly energetic and, during its interaction with the sample, it carries part of its energy to the sample mainly in the form of heat. If the sample consists of a material that is sensitive to the electron beam, this interaction can damage part or their entire structure. In this case, sputter-coating with a material that is not beam-sensitive can act as a protective layer against such kind of damage.
    • Non-conductive materials
      Another class of materials that is frequently subjected to sputter coating is non-conductive materials. Due to their non-conductive nature, their surface acts as an electron trap. This accumulation of electrons on the surface is called “charging” and creates the extra-white regions on the sample that can be seen in Fig1a, which can influence the image information.

    In order to remove this artefact, a common approach is to lower the vacuum level inside the chamber. This introduces positively-charged molecules near the surface of the sample. These interact with the charging electrons and neutralise them, thereby removing this charging effect. This has proven to be an effective approach, however the air molecules that are introduced in the vacuum chamber interact with the primary electrons reducing the quality of the image.

    For this reason, if a high-quality electron image is required, the use of sputter coater is recommended; the conductive coating material acts as a channel that allows the charging electrons to be removed from the material. In Figure 1b you can see how the charging effect has been removed with the application of a gold coating.

    Figure 1: a) Charging effect on a non-conductive sample and b) BSD imaging of this sample after 10 nm gold coating.

    In some cases, the sputter coating sample preparation technique can be used to improve image quality and resolution. Due to their high conductivity, coating materials can increase the signal-to-noise ratio during SEM imaging and therefore produce better quality images.

    The drawbacks of sputter coating for SEM

    As can be easily understood, there are a few concerns when it comes to using sputter coating for SEM imaging. Initially, it requires additional time and effort by the user to define the optimal coating parameters.

    However, there is an even more important downside of sputter coating; the surface of the sample does not contain the original material but the sputter-coated one, and therefore the atomic number-contrast is lost.

    In some extreme cases, it may lead to altered surface topography or false elemental information about the sample. Nevertheless, in most cases, the parameters of the sputter coating procedure are carefully selected and these issues do not appear and therefore the user is able to acquire high-quality images that carry the type of information that is required.

    Which materials should you use to sputter-coat your sample?

    Historically, the most used sputter coating material has been gold, due to its high conductivity and its relatively small grain size that enables high-resolution imaging. Also, if EDX analysis is required, SEM users typically coat their samples with carbon because carbon’s X-ray peak does not conflict with the peak of any other element.

    Nowadays, people are also using other coating materials with even finer grain sizes such as tungsten, iridium or chromium when ultra-high resolution imaging is required. Other coating materials include, platinum, palladium and silver, with the latter having the advantage of reversibility.

    It goes without saying that certain type of samples need some extra steps of sample preparation to achieve the best possible result in the SEM.

    Topics: Sample Preparation, Sample Degradation

    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 characterization methods.

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