Modern particle-physics experiments and many other fields of science increasingly require thin, low-mass sensors capable of measuring both the position and time of particle hits with extreme precision. However, current detector technologies are limited by the physical and technical constraints of hybrid architectures, where the sensing and readout elements are fabricated separately and connected through complex, costly assembly steps. This limits scalability, increases latency, and makes the deployment of large detection areas prohibitively expensive.
The MONOLITH project introduces a novel silicon-sensor structure, the patented monolithic Picosecond Avalanche Detector (PicoAD), designed to overcome these intrinsic limitations. The PicoAD provides picosecond-level timing and high spatial resolution simultaneously, implemented in a fully monolithic CMOS process. This approach removes the need for hybridization, dramatically reduces cost and complexity, and enables large-scale production using standard microelectronics fabrication lines.
The technological breakthrough achieved by MONOLITH goes well beyond the boundaries of particle physics. The ability to detect particles and photons with tens of picoseconds time precision and micrometric spatial accuracy has transformative potential across multiple domains. In fundamental science, the PicoAD concept offers a sustainable, scalable solution for the next generation of experiments at hadron colliders, in nuclear and astroparticle physics, and for space-borne cosmic-ray and solar-physics missions, where lightweight, radiation-hard, and high-performance sensors are essential.
In applied science and technology, the same innovations can enable significant societal benefits:
• In medical imaging, particularly Time-of-Flight PET and X-ray imaging, the detector ultra-fast response can improve image quality and reduce patient radiation dose.
• In autonomous systems, including LiDAR for self-driving vehicles, robotics, and drone navigation, they can provide real-time 3D vision with improved depth accuracy and lower latency, directly enhancing safety and reliability.
• In quantum photonics and precision metrology, the combination of fast timing and CMOS integration opens new possibilities for compact, scalable sensing systems.
By demonstrating that such high performance can be achieved in standard CMOS technology, MONOLITH contributes to European leadership and sustainability in semiconductor innovation, a key strategic area for science, technology, and industry.
The overall goal of the MONOLITH project is to realize and demonstrate a new generation of monolithic silicon detectors combining:
1. Picosecond-level time resolution,
2. High spatial precision and efficiency, and
3. Cost-effective, scalable CMOS manufacturing.
To achieve this, the project integrates advanced device simulation, ASIC design, microfabrication, and testbeam validation to prove the PicoAD sensor concept.
Specific objectives include:
• Demonstrating that monolithic timing detectors can reach and surpass the performance of hybrid pixel detectors at a fraction of the cost.
• Establishing a technology platform adaptable for diverse domains, from collider experiments to medical and industrial imaging, autonomous sensing, and quantum detection.
• Creating a sustainable innovation pathway, exemplified by the establishment of a spin-off company that will transfer the PicoAD technology to real-world applications.
In essence, MONOLITH transforms a fundamental instrumentation challenge into a broad technological opportunity, offering a single, scalable detector concept that unites scientific discovery and societal innovation.
