Fundamental limits of scintillation detector timing precision

Area of Science:

• Nuclear Instrumentation
• Detector Physics

Background:

• Scintillation detectors are crucial for precise timing measurements in various scientific fields.
• Optimizing timing precision is essential for applications like PET imaging and high-energy physics.

Purpose of the Study:

• To identify and quantify the primary factors affecting scintillation detector timing precision.
• To estimate the practical limits of timing precision for specific detector materials (Lu2SiO5:Ce and LaBr3:Ce) at 511 keV.
• To develop an empirical formula for predicting timing precision based on key parameters.

Main Methods:

• Utilized Monte Carlo simulations to model the influence of numerous parameters on timing precision.
• Investigated factors including photoelectron yield, scintillator and photodetector response times, and interaction depth uncertainty.
• Calculated timing precision for a wide range of parameters and compared results with experimental data.

Main Results:

• Photoelectron yield (A) was identified as the dominant factor influencing timing precision (R), following R = BA(-1/2).
• An empirical formula was derived to fit the calculated parameter B with high accuracy (2.2% rms deviation).
• Theoretical lower bounds for timing precision were established, showing potential for significant improvement over leading-edge timing discrimination.

Conclusions:

• Achieving 8 ps timing precision at 511 keV is theoretically possible with current photodetectors and a hypothetical scintillator producing 10,000 photoelectrons/ns.
• The study provides a framework for optimizing scintillation detector design for enhanced timing performance.
• Further development of high-light-yield scintillators is critical for advancing timing resolution in nuclear detectors.