Time calibration studies for the Timepix3 hybrid pixel detector in electron microscopy

Abstract

Direct electron detection is currently revolutionizing many fields of electron microscopy due to its lower noise, its reduced point-spread function, and its increased quantum efficiency. More specifically to this work, Timepix3 is a hybrid-pixel direct electron detector capable of outputting temporal information of individual hits in its pixel array. Its architecture results in a data-driven detector, also called event-based, in which individual hits trigger the data off the chip for readout as fast as possible. The presence of a pixel threshold value results in an almost readout-noise-free detector while also defining the hit time of arrival and the time the signal stays over the pixel threshold. In this work, we have performed various experiments to calibrate and correct the Timepix3 temporal information, specifically in the context of electron microscopy. These include the energy calibration, and the time-walk and pixel delay corrections, reaching an average temporal resolution throughout the entire pixel matrix of $1.37\pm 0.04$ ns. Additionally, we have also studied cosmic rays tracks to characterize the charge dynamics along the volume of the sensor layer, allowing us to estimate the limits of the detector's temporal response depending on different bias voltages, sensor thickness, and the electron beam ionization volume. We have estimated the uncertainty due to the ionization volume ranging from about 0.8 ns for 60 keV electrons to 8.8 ns for 300 keV electrons.

References in corpus (10)

• Ultrafast transmission electron microscopy using a laser-driven field emitter: femtosecond resolution with a high coherence electron beam
• Cavity-mediated electron-photon pairs
• Event driven 4D STEM acquisition with a Timepix3 detector: microsecond dwell time and faster scans for high precision and low dose applications
• Cathodoluminescence excitation spectroscopy: nanoscale imaging of excitation pathways
• Spatial and spectral dynamics in STEM hyperspectral imaging using random scan patterns
• $\mu$eV electron spectromicroscopy using free-space light
• Time Resolution Studies with Timepix3 Assemblies with Thin Silicon Pixel Sensors
• Timing performance of the Timepix4 front-end
• Improving the temporal resolution of event-based electron detectors using neural network cluster analysis
• Excitation's lifetime extracted from electron-photon (EELS-CL) nanosecond-scale temporal coincidences

Cited by in corpus (4)

• Nanosecond nanothermometry in an electron microscope
• Removing constraints of 4D-STEM with a framework for event-driven acquisition and processing
• Improving the temporal resolution of event-based electron detectors using neural network cluster analysis
• Advancing Time-Resolved Spectroscopies with Custom Scanning Units and Event-Based Electron Detection