Silicon 3D Microdetectors for Microdosimetry in Hadron Therapy

Area of Science:

• Nuclear Science and Engineering
• Medical Physics
• Microelectronics

Background:

• Particle therapy requires precise characterization of radiation beams at the microscale.
• Existing microdosimeters face challenges in noise, spatial resolution, and pile-up robustness.
• The National Microelectronics Center (IMB-CNM, CSIC) has focused on developing advanced microdosimeters.

Purpose of the Study:

• To describe the evolution and development of new 3D microdosimeters.
• To summarize the design, manufacturing, and electrical characterization of these devices.
• To assess their suitability for particle therapy applications, particularly hadron therapy.

Main Methods:

• Development of ultra-thin 3D diodes (U3DTHINs) and 3D cylindrical microdetectors.
• Design and fabrication of sensors with electrodes inserted into silicon bulk.
• Electrical characterization and experimental testing on carbon and proton beamlines (GANIL, CNAO).

Main Results:

• The 3D microdosimeters exhibit low noise, well-defined sensitive volumes, high spatial resolution, and pile-up robustness.
• 3D cylindrical architecture successfully mimicked mammalian cell sizes for microdosimetric assessment.
• Experimental tests confirmed feasibility in hadron therapy beams with good performance at high fluence rates without saturation.

Conclusions:

• These advanced 3D microdosimeters are suitable for characterizing microdosimetric properties in hadron therapy.
• Improvements in microfabrication enhanced charge collection efficiency (CCE) in the latest generation.
• Further study and discussion address potential limitations such as CCE and electronic noise.