The data were collected by an optical time projection chamber (detailed in: https://iopscience.iop.org/article/10.1088/1748-0221/5/12/P12004).

Calibration data are included, where a radioactive alpha-particle emitter was placed inside the chamber.

The remainder of the data were collected with beam from the HIGS facility entering the detector to induce nuclear reactions.

Typical data files with gamma-beam were acquired over hour-long periods.