Preparing Timepix3 for deployment in low-radioactivity natural settings: an integrated workflow for charged particle detection and imaging

The natural sedimentary environment possesses a mixed field of α-, β-, and γ-radiation emitted from the radioactive decay of radionuclides such as potassium-40 (K-40), uranium-238 (U-238), and thorium-232 (Th-232). These emissions are responsible for dose accumulation in feldspar and quartz mineral grains, forming the basis of luminescence dating. The inhomogeneous spatial distribution of radionuclides in sediments and local energy deposition at the grain level can cause microdosimetric variations, contributing to overdispersion in equivalent dose (D_e) distributions. Understanding and resolving these variations requires a detector that can simultaneously map various types of radiation and their energy deposition at the micron scale. Here we present a workflow for configuring and applying Timepix3 (silicon-based hybrid pixel detector, 14 × 14 mm2 active area, 256 × 256 pixels, 300 μm thickness) for high-sensitivity imaging of α- and β-particles simultaneously in mixed-radiation fields. The workflow includes particle-track reconstruction, charged-particle identification, background suppression, and energy calibration with a mixed α-particle source (Pu-239, Am-241, Cm-244; 5.15–5.80 MeV) in air. A linear energy calibration response was obtained; however, the detector was unable to fully resolve three α-particle peaks. While this appears to be a limitation, it ultimately provides insights into the detector's response under conditions that closely mimic the energy spectra of natural radiation, broad energy distributions, and measurement conditions such as ambient atmospheric pressure.