A Study of Position-Sensitive Solid-State Photomultiplier Signal Properties

Area of Science:

• Medical Physics
• Instrumentation
• Nuclear Science

Background:

• Position-sensitive solid-state photomultipliers (PS-SSPMs) offer large areas and high spatial resolution for scintillator-based detectors.
• However, their design introduces challenges like high capacitance and low-pass filtering, which degrade signal speed and introduce position-dependent timing delays.

Purpose of the Study:

• To analyze the signal properties of PS-SSPMs with integrated resistive networks for position sensing.
• To characterize timing resolution and time delay variations across different PS-SSPM designs and scintillator crystal sizes.
• To evaluate the effectiveness of digital timing methods for improving detector performance.

Main Methods:

• Characterized timing resolution and position-dependent time delays for continuous and tiled PS-SSPM designs.
• Investigated the impact of scintillator crystal size on timing resolution.
• Studied digital timing methods and their effect on signal amplitude, flood histogram quality, and depth-of-interaction resolution.

Main Results:

• Observed significant position-dependent signal shape changes and timing delays in PS-SSPMs.
• Achieved block timing resolutions of 8.6 ns and 8.5 ns after time delay correction for 10 mm and 5 mm PS-SSPMs, respectively.
• Found a slight improvement in timing resolution with smaller scintillator crystals (0.5 mm vs. 1.3 mm).
• Digital timing methods showed promise for accurate timing and improved positioning.

Conclusions:

• Detector timing and positioning in PS-SSPMs can be substantially enhanced by employing digital timing techniques.
• Accounting for position-dependent signal shape variations is crucial for optimizing performance.
• These advancements are vital for improving the accuracy and efficiency of imaging systems utilizing PS-SSPMs.