Enhancing timing performance of heterostructures with double-sided readout.

Area of Science:

• Nuclear Instrumentation
• Medical Physics
• Materials Science

Background:

• Heterostructured scintillators offer potential for balancing sensitivity and timing in Time-of-Flight Positron Emission Tomography (TOF-PET) detectors.
• Layering in scintillators can compromise time resolution due to light transport issues.
• Double-sided readout (DSR) is explored to enhance light collection and Depth-of-Interaction (DOI) information retrieval.

Purpose of the Study:

• To assess the impact of DSR on the time resolution and DOI performance of BGO&EJ232 heterostructures.
• To investigate the intrinsic capture of DOI information using DSR.

Main Methods:

• Evaluated 3x3x20 mm³ BGO&EJ232 heterostructures using single-sided readout (SSR) and DSR configurations.
• Employed high-frequency electronics for precise timing measurements.
• Measured Coincidence Time Resolution (CTR) and DOI resolution.

Main Results:

• Achieved a DOI resolution of 6.4 ± 0.04 mm.
• Improved CTR from 262 ± 8 ps (SSR) to 174 ± 6 ps (DSR) when measured against a reference detector.
• In a symmetrical DSR configuration, achieved CTR of 254 ± 8 ps (all photopeak events) and 107 ± 5 ps (fastest events).

Conclusions:

• High-frequency DSR effectively measures DOI resolution and enhances heterostructure time resolution by up to 40%.
• DOI information is intrinsically captured by averaging timestamps from dual silicon photomultipliers (SiPMs) without additional correction.
• DSR is a promising technique for advancing TOF-PET detector performance.