Nanopattern multi-well avalanche selenium detector for TOF-PET.

Area of Science:

• Materials Science
• Particle Detectors
• Medical Imaging Physics

Background:

• Amorphous selenium (a-Se) is explored as a photoconductive material for time-of-flight (TOF) detectors.
• Existing a-Se detectors face challenges with poor time resolution and low carrier mobility due to shallow traps.
• Avalanche-mode a-Se offers advantages like high fill factor and low excess noise but requires improved time resolution.

Purpose of the Study:

• To propose and evaluate a nanopattern multi-well a-Se detector (MWSD) for TOF applications.
• To overcome the limitations of a-Se in terms of time resolution and carrier mobility.
• To demonstrate the potential of MWSD for low-statistics photon imaging, such as Positron Emission Tomography (PET).

Main Methods:

• Development of a nanopattern multi-well a-Se detector (MWSD).
• Integration of impact ionization avalanche gain and unipolar time-differential (UTD) charge sensing.
• Experimental validation and analysis using Cramér-Rao lower bound and Monte Carlo simulations.

Main Results:

• UTD charge sensing in avalanche-mode a-Se achieved a nearly 4-orders-of-magnitude improvement in time resolution.
• The MWSD demonstrated viability for low statistics photon imaging modalities like PET.
• The device operates in linear mode, offering potential for 100 ps coincidence time resolution in TOF PET.

Conclusions:

• The proposed MWSD effectively enhances the time resolution of amorphous selenium detectors.
• This technology presents a low-cost, scalable solution for advanced photon imaging applications.
• The device shows significant promise for achieving high-resolution TOF PET imaging.