Estimate interaction timing in a large volume HgI₂ detector using cathode pulse waveforms.

Area of Science:

• Nuclear physics
• Materials science
• Detector technology

Background:

• Traditional timing resolution methods in detectors face challenges like slow charge carrier mobility and pulse shape variations.
• Depth-dependent detector response can further complicate accurate timing measurements.

Purpose of the Study:

• To present experimental results on timing resolution using a 5 mm thick Mercuric Iodide (HgI2) detector.
• To evaluate a novel method for deriving timing information from detector pulse waveforms.
• To compare the effectiveness of different waveform models for precise interaction time estimation.

Main Methods:

• Utilized a 5 mm thick HgI2 detector and a BaF2 coincidence detector.
• Acquired cathode pre-amplifier pulse waveforms using a digital oscilloscope.
• Estimated interaction times by fitting measured waveforms to pre-defined models, bypassing conventional triggering methods.

Main Results:

• Achieved a timing resolution of 13 nanoseconds (ns) for 511 keV full energy events.
• Demonstrated that waveform fitting significantly reduces issues associated with leading edge or constant fraction triggering.
• Showcased the potential of HgI2 detectors for high-resolution timing applications.

Conclusions:

• Waveform model fitting offers a superior approach to timing resolution compared to conventional methods for HgI2 detectors.
• The developed method effectively mitigates common detector response artifacts, enabling precise timing.
• This advancement holds promise for applications requiring accurate event timing in particle physics and medical imaging.