Quantum Detectors Ltd: Event- and frame-based detection with Merlin T4 for Transmission Electron Microscopy
Authors
Matus Krajnak (1), Gearoid Mangan (1)
Affiliations
- Quantum Detectors Ltd
Room: Workshop 3
We are excited to present our most advanced technology yet: the Merlin T4, a versatile direct electron detector (DED) capable of both frame- and event-based operation, specifically designed for cutting-edge applications in Transmission Electron Microscopy (TEM).
Event- and frame-based detection with the Merlin T4 represents a major leap forward in electron microscopy. Built on the advanced Timepix4 CERN ASIC technology [1], the Merlin T4 combines the strengths of both acquisition modes in a compact, TEM-compatible form factor. It delivers rapid full-frame readouts at up to 40 kHz in frame-based mode, ideally suited for high electron flux applications. Meanwhile, the event-based mode enables native scanning transmission electron microscopy (STEM) speeds by capturing individual electron events, each encoded with time of arrival (ToA), time over threshold (ToT), and pixel position at an exceptional temporal resolution of 200 ps.
This unique capability of measuring both high flux and precise temporal data empowers a wide range of TEM applications. These include sub-microsecond dwell time four-dimensional STEM (4D-STEM) or scanning electron diffraction, ultrafast TEM (UTEM) for visualising dynamic processes and temporal correlations, rapid spatially-resolved electron energy loss spectroscopy (EELS), and three-dimensional electron diffraction (3D-ED). Event-driven acquisition offers major advantages over traditional frame-based techniques, particularly when acquisition rates drop below the microsecond range. Capturing single-electron events with precise timing enables faster acquisition, reduces sample drift artefacts, and supports lower electron doses.
Moreover, the data efficiency of event-based acquisition in momentum-resolved STEM is remarkable. For instance, a 50 pA electron current dataset with 1k × 1k scanning positions and a 1 µs dwell time may result in only 20–50 GB of data in event mode, compared to over 1 TB using frame-based acquisition.
In our workshop, we will showcase initial 4D-STEM data acquired with the Merlin T4 and explore its potential across various TEM applications. We will also highlight data analysis approaches and discuss the transformative impact of event-driven acquisition on microscopy workflows and data management.
[1] Llopart, et al., Journal of Instrumentation 17.01 (2022): C01044