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MerlinEM
Quantum Detectors at NTNU
Quantum Detectors spoke to Prof. Ton van Helvoort and head engineer Dr. Emil Christiansen from NTNU in Norway to understand why they have chosen to put two MerlinEM detectors on their microscopes and how this has benefited their research so far, and to learn of their future plans.
The TEM activities within Natural Sciences and technologies at Norway’s largest university NTNU are coordinated in the TEM Gemini Center in Trondheim. The lab is a node in the national facility NORTEM and currently has three TEMs with two MerlinEM detectors. The JEOL 2100F FEGTEM has the MerlinEM 1S detector in a bottom-mounted position since September 2020 and currently, a MerlinEM 4R detector has been installed on the double-corrected JEOL ARM 200F.
Ton is a Professor at the Department of Physics at the Norwegian University of Science and Technology (NTNU) and one of the main people in the TEM Gemini Centre in Trondheim, Norway, and the large national TEM infrastructure project NORTEM. At the moment Ton is working on quantitative HAADF STEM & quantitative energy dispersive spectroscopy and the development of optoelectronic devices based on III-V nanowires.
Emil is working as a senior engineer at the NORTEM laboratories within the Department of Physics, where he trains new users, serves projects as a for-hire operator, maintains and develops the TEM infrastructure, investigates new TEM methods and applications, and works with the strategic development of the infrastructure.
How has the MerlinEM helped improve your research?
Our users, over 40 hands-on and over 100 different projects per year, cover a broad range of materials. 4D STEM techniques benefit from direct electron detectors. For our activities especially scanning precession electron diffraction (SPED) is central for phase and orientation mapping. Compared to the conventional way with an external camera, the Merlin data collection has a night and day difference. For example, for strain measurements and analyzing weak signals from small particles in a strongly diffracting matrix. In addition, in the last two years work on field mapping in ferroic materials has become an important focus point.
What are your intentions/goals for your research?
As a national center, we have to give access to advanced and new microscopy techniques within Norway. With the Merlin system, we improved SPED data quality and explored how the limitations of SPED for semi-automatic phase and orientation analysis of technological important materials, specifically light metals. This requires integration of data collection and data analysis, and we actively contribute to open-source developments, primarily HyperSpy and pyXem. For our students acquiring skills in that direction is useful for their future careers.
[Dr. Emil Frang Christiansen, senior engineer, operating the JEOL ARM200F microscope where the MerlinEM 4R is installed at NTNU Trondheim]
Which feature of the MerlinEM has been the most helpful?
Having full control and low noise is crucial. However, as a university, teaching the next generation of scientists and engineers is important. Being able to see the intensity variations in the beam and diffracted signal live has proven to be very helpful for the student’s understanding and appreciation of electron diffraction. We choose to first install the system on an uncorrected FEGTEM. This made the technology accessible to a larger number of users. This has undoubtedly helped us to understand the possibilities and limitations. Now we look forward to using the Quad on our double-corrected ARM.
[Elisabeth Thronsen PhD student, Dr. Emil Christiansen SenEng using the precession electron diffraction toolkit from NanoMegas and the MerlinEM detector to collect fast and high-quality aluminium precipitate diffraction data.]
How long have you worked with Quantum Detectors?
Since September 2020, slightly delayed due to the pandemic on the JEOL 2100F in connection with a NanoMegas scanning precession system. From the end of August 2022, we will use a Quad on the double-corrected ARM. Prior to this, we had to travel abroad to take data on different direct electron detectors.
Why do you enjoy working with Quantum Detectors?
The reliability and the quality of the data of the detectors, but also the low threshold support and continued collaboration for improving our detection solutions. This helps to fix technical issues swiftly and develop tailored and unique solutions.
What would you like to see from QD in the future?
There are plenty of ideas and in our lab, new materials and questions always pop up. A large part of our international collaborations come from exploring the detector in connection to SPED and data processing.
Currently, we use the detector for a 200 kV beam and that is not optimal. On our list is exploring low dose and other voltages. With the experience of having the system in a multiuser lab and having set up the post-acquisition routines, it would be interesting to use a similar system for imaging and diffraction on a scanning electron microscope at 1-30 kV.
[MerlinEM 4R installed on the JEOL ARM200F microscope at NTNU Trondheim]
Publications
MerlinEM
Quantum Detectors at ePSIC
We speak to Dr Chris Allen about his experience of using the MerlinEM 4R at the electron Physical Science Imaging Centre (ePSIC), a national facility for aberration corrected electron microscopy.
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