In this interview, Fernando C. Castro, Ph.D., an Applications Scientist at Gatan, talks to AZoMaterials about the new ClearView camera and its utility across a wide range of techniques for transmission electron microscopy.
What is the ClearView camera, and how does it enhance transmission electron microscopy?
ClearView® is a new scintillator camera developed by Gatan that offers significant benefits for transmission electron microscopy (TEM) analysis. It provides a highly versatile toolset for researchers to enhance not only their routine TEM imaging but also any in-situ and 4D STEM (four-dimensional scanning transmission electron microscopy) experiment.
ClearView brings a whole new level of capabilities compared to its predecessor, the OneView camera. In general, the camera offers 4k x 4k imaging and has a higher dynamic range thanks to the sensor's HDR readout capability, less noise, faster framerates, and many more options for controlling the acquisition to meet demanding experimental requirements and maximizing data quality. The improved camera performance makes it a better camera for essentially all supported microscopy applications, especially in-situ and 4D STEM.
One of my favorite new camera features is the Frame Control mode, which allows users to adjust the camera frame rate dynamically to reduce noise levels in an image and maximize signal-to-noise. The camera can also reach framerates up to 1,600 frames per second which removes many experimental barriers found with in-situ and 4D STEM requirements that require high-speed capabilities. To do this, ClearView utilizes advanced sub-area sensor readout options that are not found on previous Gatan scintillator cameras. As with all other Gatan cameras, ClearView is controlled with the DigitalMicrograph® software, and it should be easy for users of all experience levels to get started quickly with the ClearView camera.
Large field of view, high-resolution imaging of Au particles with ClearView.
Image Credit: Gatan, Inc.
Can you provide more details about the Frame Control mode of ClearView and how it is useful?
When conducting microscopy experiments, there are often situations where you have to resolve low-contrast details in images or weak features in diffraction patterns. You can always try to increase the beam intensity to improve the signal-to-noise in the data, but there are often limits to how intense you can go due to other factors with the sample, microscope, or camera. Many times it is useful to instead try to reduce the noise being integrated into the acquired data. These are the cases where Frame Control Mode comes to the rescue.
One of the main sources of noise in a camera image can be the read-out noise, which is a fixed amount of noise that is present in the data every time the camera reads out a frame. The ClearView camera acquires single images by capturing many frames at a given framerate and summing them together into a final output image. ClearView, by default, runs at a very high framerate, which is great for high-speed applications but can complicate image acquisition at low signal conditions since you will sum together many frames and possibly a significant amount of read-out noise into the final image.
With Frame Control mode, you can adjust the camera framerate and decrease it to framerates that better match the imaging requirements. By decreasing the framerate when needed, there is less read-out noise introduced into the final image because fewer frames get read out. Moreover, each pixel in each frame also has much more signal, so you make better use of the charge capacity and dynamic range of the pixels in the sensor. The final result of using Frame Control mode is a higher quality image with improved signal-to-noise and a higher likelihood of resolving those important subtle, low-contrast features in the data.
Better resolve faint, high-resolution diffraction spots with ClearView Frame Control mode.
Image Credit: Gatan, Inc.
The example silicon [110] diffraction pattern shown here highlights the ability to resolve weak, high-resolution spots in a diffraction pattern when using Frame Control. The most intense spot in the pattern had over 250,000 counts, and the faintest spot (spot #1) corresponding to sub-1 Angstrom resolution had less than 200 counts. Without utilizing Frame Control to reduce background noise, it is likely that we would not have been able to resolve such high-resolution features in the diffraction pattern.
So, the Frame Control Mode does not just improve image quality but also offers flexibility. It gives you the power to fine-tune the camera's performance based on the specific demands of your experiment. This is especially valuable for microscopists doing a lot of electron diffraction analysis or imaging low-contrast samples like those in the pathology space.
What specific advantages does the high dynamic range readout of the ClearView offer, and in which applications is it most beneficial?
The high dynamic range (HDR) readout in the ClearView camera benefits all applications requiring high dynamic range. The most obvious application that benefits from the HDR readout is electron diffraction, including selected area diffraction and 4D STEM techniques. The HDR readout of the ClearView camera also gives it a much higher dynamic range than its predecessor, the OneView® camera.
In the previous example of using Frame Control to acquire a diffraction pattern, the HDR readout of the camera is one of the main reasons that we could acquire a diffraction image with such a large variation in the intensities of the diffraction spots.
In 4D STEM experiments, people often want to look at intensity differences between diffraction disks and at changes in contrast within disks. The improved dynamic range from the HDR readout will be essential for those kinds of subtle feature analysis. As a result, the ClearView camera is an excellent choice for researchers in materials science and nanotechnology applications.
4D STEM and Virtual Aperture Imaging with ClearView.
Image Credit: Gatan, Inc.
How does DigitalMicrograph aid users in efficiently capturing, processing, and analyzing data acquired with the ClearView camera?
DigitalMicrograph plays a crucial role in supporting users in the efficient processing and analysis of data acquired with the ClearView camera. This comprehensive software offers a range of tools and features designed to streamline the workflow, making it easier to work with large datasets and derive valuable insights from the acquired data.
DigitalMicrograph provides intuitive controls that allow users to set up and configure the ClearView camera for data acquisition. Whether you are interested in in-situ experiments, diffraction, or 4D STEM, DigitalMicrograph has a user-friendly interface that assists in choosing the appropriate camera settings. As discussed, the DigitalMicrograph interface is also where you can set up the Frame Control mode for maximizing signal-to-noise in your data and also for changing binning and sub-area readout options to increase the camera framerate.
One standout feature for standard imaging experiments is the live drift correction that can be easily turned on in the software and automatically applied to single image acquisitions. If the sample is drifting due to stage instability or beam effects, the live drift correction helps tremendously and enables the acquisition of sharp, high-resolution images even with sample drift.
Live drift correction during imaging acquisition.
Image Credit: Gatan, Inc.
Since in-situ experiments can be very complicated, Gatan has developed a lot of tools for collecting and analyzing in-situ data. One very useful in-situ feature in DigitalMicrograph is the LookBack™ function for in-situ video data collection, which acts as a video buffer to temporarily record data before you officially hit the record button. This means that you can start recording data only after the reaction of interest has started, and you still will not miss the start of an in-situ reaction or other time-sensitive event as it will have been captured by the LookBack buffer. It is a valuable tool for researchers interested in capturing dynamic processes while minimizing unnecessary data capture.
Another useful in-situ acquisition feature in DigitalMicrograph is Time-Lapse, which allows users to capture extended in-situ experiments more efficiently. Some experiments can span hours, and this feature lets users save data at longer intervals of time or number of frames. As a result, the camera can efficiently capture in-situ data during these lengthy experiments and avoid having unmanageable total file sizes.
With respect to in-situ data analysis, DigitalMicrograph offers its In-Situ Player and In-Situ Editor tools. These tools enable in-situ data playback, including synchronization of in-situ holder metadata. You can also use the tools to do post-processing drift correction to the in-situ video data, process the video to reduce file size, edit the start and end points of the data, and export the data to video.
As for 4D STEM, it is very straightforward to collect 4D STEM data and do common analysis in DigitalMicrograph like virtual bright-field/dark-field imaging, strain mapping, and differential phase contrast (DPC) imaging. DigitalMicrograph also supports Python scripting, so users can do all kinds of custom data collection and processing with Python scripts.
What are the binning and sub-area readout functions of ClearView and their respective impacts on data acquisition?
Binning and sub-area readouts are two different ways of adjusting the camera image size and increasing the framerate for applications requiring high-speed data collection. As a result, the two functions have big impacts on how well ClearView works for in-situ and 4D STEM data acquisition.
Binning combines signal from multiple pixels into a single pixel, which does two key things. First, it improves the signal per pixel, which is a useful tool for all applications. Binning also enables the camera to read out at a faster framerate since there will be a smaller total number of pixels per frame to read out. With binning alone, you can increase the camera framerate to 200 frames per second at a 2k x 2k image size, which is very valuable for in-situ experimentation where you want to observe and record changes in a sample over time with both high temporal and spatial resolution.
However, it is important to keep in mind that binning impacts the spatial resolution of your images. When you bin, you are essentially increasing your pixel size, which may affect your ability to the resolve high-resolution spatial information you are looking for. Nevertheless, this trade-off between frame rate and spatial resolution is a powerful tool when used strategically, and you can always compensate by changing the microscope magnification.
Sub-area readout is another feature that impacts data acquisition. When you use sub-area readout, you can select a specific region of your sensor for readout without changing your pixel size. This results in framerate increases while maintaining your spatial resolution, which is highly advantageous. The trade-off instead comes from a decreased field of view.
ClearView users have the ability to combine both binning and sub-area readout to achieve the framerate, field of view, and image resolution they need to best match their experiment. At its fastest framerate, ClearView can acquire data at 1,600 frames per second using 2x binning and one-eighth sub-area readout. The resulting image size is small, but it is sufficient for capturing many types of diffraction images, and the high framerate means that large-area 4D STEM scans can be acquired very rapidly. The achievable speeds of ClearView provide a significant advantage for data collection.
Can you elaborate on the synchronization of in-situ holder metadata with camera data and its significance in experiment analysis?
ClearView uses the DigitalMicrograph software for acquiring all data with the camera, including in-situ video data. During an in-situ experiment, DigitalMicrograph can also communicate with many different in-situ holders to get metadata information from the holder during the experiment. DigitalMicrograph then takes the ClearView video data and holder metadata and automatically synchronizes them during data playback and analysis.
ClearView and DigitalMicrograph can work seamlessly with various in-situ holders, so there are many different types of metadata, like holder temperature, applied current, measured resistance, etc., that can be acquired during the experiment and automatically synchronized. When you are conducting in-situ experiments, especially those involving dynamic or time-dependent processes, having access to this metadata is invaluable.
ClearView camera.
Image Credit: Gatan, Inc.
Now, the significance of this automatic data synchronization is twofold. First, it ensures that we have a precise record of the experimental conditions at each moment during data acquisition. This helps us understand how variations in parameters might correlate with changes in the acquired data. For instance, if you observe material transformations at elevated temperatures, knowing the exact temperature at which certain events occur can be critical for your analysis.
Secondly, it simplifies the analysis process. When reviewing the acquired data, you can view the metadata alongside the video data, which directly correlates between experimental conditions and the observed phenomena. This can aid in identifying patterns, trends, or specific responses within the data, which may otherwise be challenging to interpret.
Are there any upcoming developments or features in the ClearView camera that users can look forward to?
Gatan is committed to continuous innovation and improvement. The ClearView camera is part of a broader initiative aimed at pushing the boundaries of what is possible in transmission electron microscopy.
The latest version of DigitalMicrograph, which comes with the ClearView camera, unlocks a ton of new capabilities for users, especially in the in-situ and 4D STEM space. The in-situ data processing tools have been revamped to be more powerful and more user-friendly. You can now do in-situ 4D STEM experiments with ClearView and DigitalMicrograph, and also capture energy dispersive x-ray spectroscopy (EDS) data simultaneously with 4D STEM data. There are also many other different electron diffraction techniques that the microscopy community is interested in, and we hope to continue to expand the capabilities of ClearView and DigitalMicrograph in those spaces to help users collect data using new, emerging techniques.
Fernando Castro, Ph.D.
Fernando holds a B.S. in Chemistry from the University of Chicago, a Ph.D. in Materials Science and Engineering from Northwestern University, and has been working in the field of electron microscopy for over 10 years. He developed his expertise in TEM and SEM through his research experience on nanomaterials and lithium-ion battery materials and is well-versed in many of the key EM techniques for analyzing materials science samples. Fernando joined Gatan after completing his Ph.D., where he is now an Applications Scientist in charge of supporting Imaging and Diffraction products.
This information has been sourced, reviewed and adapted from materials provided by Gatan, Inc.
For more information on this source, please visit Gatan, Inc.
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