Cherenkov Light Emission in Pure Cherenkov Emitters for Prompt Gamma Imaging

Area of Science:

• Medical Physics
• Nuclear Instrumentation
• Materials Science

Background:

• Proton range verification (PRV) is crucial in proton therapy for accurate dose delivery.
• Prompt-gamma detection faces challenges due to high count rates, broad energy spectra (1-7 MeV), and significant background noise.
• Cherenkov light emission offers a potential solution for fast timing and signal discrimination.

Purpose of the Study:

• To investigate the potential of Cherenkov light generated by prompt-gammas in TlBr, TlCl, and PbF2 crystals for PRV.
• To evaluate the performance of different crystal dimensions and photodetector configurations for prompt-gamma detection.
• To identify the most suitable material and configuration for efficient and accurate PRV.

Main Methods:

• Simulations were performed using TlBr, TlCl, and PbF2 crystals of varying dimensions (1x1 cm^2 with 1-4 cm thickness).
• The study analyzed Cherenkov photon generation for prompt-gamma energies of 2.3 MeV, 4.4 MeV, and 6.1 MeV.
• Different photodetector configurations and efficiencies were modeled to assess detection performance.

Main Results:

• TlCl consistently yielded the highest number of detected Cherenkov photons across all simulated energies, crystal dimensions, and photodetector efficiencies.
• For the highest energy (6.1 MeV), TlCl with a high-performance photodetector produced approximately 250 detected Cherenkov photons.
• Smaller crystal blocks (1 cm x 1 cm x 1 cm) demonstrated superior prompt-gamma detection efficiency per unit volume.

Conclusions:

• TlCl is a highly promising material for Cherenkov-based prompt-gamma detection in proton therapy.
• The Cherenkov emission in TlCl provides a fast timing signal, beneficial for high count rates and background suppression.
• Optimized crystal dimensions, particularly smaller volumes, enhance detection efficiency, paving the way for improved proton range verification techniques.