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.
ePSIC provides access to state-of-the-art transmission electron microscopes with expert support from electron microscopy scientists such as Dr. Chris Allen, spoken to here.
One of the microscopes at ePSIC is a JEOL ARM300F double-corrected microscope dedicated to atomic-scale imaging and 4D STEM studies. The microscope is equipped with Gatan and Direct Electron cameras and an Oxford Instruments EDX detector. In 2016, a demo unit of the MerlinEM 1S camera was added to the microscope to expand the capabilities for 4D STEM, dynamic TEM movie making, and ptychographic experiments. This demo was successful and a quad chip retractable Merlin, the MerlinEM 4R, was procured and added to the camera lineup.
The MerlinEM 4R is a very popular addition to this national facility, being used for many cutting-edge 4D STEM experiments.
Having a camera on a national facility with a wide range of users and expert in-house support means the microscope was a perfect test bed for new features, garnering useful feedback from a diverse community and helping us to rapidly introduce software features such as region of interest mode and live STEM reconstruction, and to work on greatly increasing our readout speed.
ePSIC and their users have really been exploring the possibilities of data collection with MerlinEM, and at last count have published 19 journal articles utilising Merlin data – referenced below.
QD: What are your goals at ePSIC?
Chris: We strive to provide access to cutting edge transmission electron microsocopy for the wider scientific community. One particular focus of ours is to enable the study of materials which are readily damaged by the electron beam. This requires the development and implementation of novel imaging techniques.
QD: What challenges were you experiencing prior to getting Merlin?
Chris: The MerlinEM direct detector has enabled us to develop techniques including ptychography and scanning nano-beam electron diffraction which we are using to perform low electron fluence studies of a wide variety of samples including perovskites for solar cells and novel battery materials. Without the detector these studies would not have been possible.
QD: Why do you like working with QD?
Chris: We’ve worked closely with QD over the last 5 years to understand and optimise the Merlin detector. We have found QD to be responsive to our feedback and requests regarding detector features and we have collaborated on a number of development projects looking forward to the next generation of detectors.
QD: What would you like to see from us in the future?
Chris: I’m excited by the speed of developments in camera technology and looking forward to the next generation of detectors. I’m particularly interested in the possibility of robust direct detector cameras for performing diffractive imaging experiments at both high (300keV and above) and low (30keV and below) accelerating voltages, as well as the possibility of cameras with faster read-out speeds.