MACACO II test-beam with high energy photons

Area of Science:

• Medical Physics
• Particle Detectors
• Nuclear Instrumentation

Background:

• Proton therapy requires precise monitoring of radiation dose distribution.
• Compton cameras offer a promising non-invasive method for treatment verification.
• Previous prototypes demonstrated the feasibility of monolithic crystal Compton cameras.

Purpose of the Study:

• To present the development and performance of the MACACO II Compton camera prototype.
• To evaluate the enhanced spatial and energy resolution of the new system.
• To validate the improved image reconstruction methods for proton therapy monitoring.

Main Methods:

• Development of a three-layer Compton camera with monolithic crystal detectors and SiPM arrays.
• Enhancement of detector energy resolution and image reconstruction algorithms.
• Testing with 4.4 MeV photons produced by an 18 MeV proton beam at the CNA.
• Acquisition of data at varying detector positions and beam intensities.

Main Results:

• Successful reconstruction of photon emission distributions from a graphite target.
• Demonstration of imaging capabilities with both two- and three-interaction events.
• Achieved accurate spatial resolution for identifying distinct target positions.
• Validated improved performance compared to the first prototype.

Conclusions:

• The MACACO II Compton camera shows significant advancements for proton therapy monitoring.
• The system's enhanced resolution and reconstruction methods enable precise localization of photon emission.
• The ability to reconstruct three-interaction events marks a key progress in Compton imaging technology.