Editorial: Particle and radiation sensors developed at INFN-CSN5

The National Scientific Commission 5 (CSN5) of the Istituto Nazionale di Fisica Nucleare (INFN) is devoted to applied, technological, and interdisciplinary research, with a strong emphasis on the development of advanced sensing and detection technologies. CSN5 operates at the interface between fundamental research and applications, promoting innovation across a broad scientific landscape that includes experimental particle physics, advanced computing, quantum technologies, and the life sciences. This multidisciplinary framework fosters cross-disciplinary approaches and enables the transfer of expertise across traditionally distinct domains.

Radiation sensors represent a central pillar of CSN5 activities and form the unifying theme of the present Research Topic. Within CSN5, sensor technologies are conceived, developed, and deployed to address a wide variety of challenges: monitoring and characterizing particle beams; detecting radiation with high spatial and temporal resolution; measuring environmental radiation; and performing accurate dosimetry in cancer radiotherapy. These capabilities naturally extend to medical imaging, the observation of radiation originating from space, and, more recently, to the development of quantum sensors capable of achieving sensitivities beyond classical limits. In this context, radiation sensors are not merely tools, but enabling technologies that connect diverse scientific fields and applications.

A distinctive feature of CSN5 is its strong commitment to technology transfer and cross-fertilization between astroparticle physics and other applied domains. Detector technologies originally conceived to address the stringent requirements of fundamental physics experiments frequently find impactful applications in medicine, environmental monitoring, security, and space science. By promoting sustained detector research and development, CSN5 contributes not only to advances in fundamental physics, but also to the broader mission of sensor science, technological innovation, and societal impact that lies at the core of Frontiers in Sensors.

This Research Topic, entitled “Particle and Radiation Sensors Developed at INFN-CSN5”, brings together twelve peer-reviewed contributions that provide a representative snapshot of the breadth, depth, and maturity of sensor research carried out within the CSN5 community. The collected works span a wide range of detector concepts, materials, and readout solutions, addressing challenges in both fundamental research and application-driven contexts. Together, they illustrate the richness of CSN5 activities and highlight the central role of particle and radiation sensors as enabling tools across physics, space science, medical applications, and emerging quantum technologies.

Several contributions focus on detector concepts driven by the needs of high-energy physics and astroparticle research. One article explores oriented-crystal electromagnetic calorimetry, demonstrating how the alignment of incoming particles with crystal axes can significantly accelerate shower development. Through an extensive research and development program, ranging from single-crystal studies to the construction of a PWO crystal matrix, this work opens new perspectives for compact, high-performance calorimeters, particularly suited for collider experiments, beam-dump facilities, and high-energy γ-ray astrophysics.

Precision timing and radiation hardness are recurring themes across multiple contributions. A comprehensive review addresses the development of Low-Gain Avalanche Diodes (LGADs) and thin silicon diodes for particle therapy applications. Compared to conventional gas ionization chambers, these detectors offer superior sensitivity and timing capabilities, enabling applications ranging from beam commissioning and monitoring to dosimetry in ultra-high dose rate and spatially fractionated radiotherapy. This work highlights the strong synergy between detector physics, electronics development, and clinical requirements.

Closely related, the outcomes of the CSN5 eXFlu project are presented in a detailed study of ultra-thin LGAD sensors. By reducing the active sensor thickness down to 15 μm, exceptional timing resolutions are achieved while maintaining remarkable radiation hardness. The demonstrated performance positions thin LGADs as key candidates for future high-precision timing applications in both fundamental physics and applied environments characterized by extreme radiation levels.

Medical applications are further addressed through a comprehensive review of silicon carbide (SiC) detectors for advanced dosimetry. Thanks to its wide bandgap, radiation tolerance, and favorable physical properties, SiC emerges as a robust alternative to conventional dosimetric materials. The article surveys detector architectures and experimental results for photon, proton, carbon-ion, and FLASH radiotherapy, highlighting the potential of SiC to meet the demanding requirements of modern treatment techniques.

Advanced silicon sensor technologies for future collider experiments are the focus of another contribution dedicated to 4D tracking. The paper reviews recent progress in sensor concepts capable of delivering excellent spatial and temporal resolution under unprecedented radiation levels. In particular, 3D silicon sensors are shown to satisfy key performance criteria, emphasizing the importance of sensor–electronics co-design and advanced fabrication techniques.

Beyond traditional semiconductor detectors, the Research Topic also reflects CSN5’s interest in novel materials and unconventional approaches. A mini-review is devoted to polysiloxane-based scintillators, highlighting their radiation hardness, mechanical flexibility, chemical versatility, and emerging applications ranging from neutron detection to real-time dose monitoring in proton therapy. Recent advances in photocurable and 3D-printable formulations further expand the design space of polymer-based radiation sensors.

Another contribution presents the achievements of the ARCADIA collaboration in the development of fully-depleted CMOS monolithic sensors. By combining fast charge collection, low power consumption, and embedded electronics, these devices address the needs of high-rate particle and photon detection, spanning applications from time-of-flight measurements to X-ray imaging.

The Research Topic also extends into the domain of quantum technologies. One article discusses integrated optics for the generation of squeezed vacuum states in lithium-niobate waveguides. These compact and robust sources have the potential to enhance precision measurements, including gravitational-wave detection, and represent a promising platform for future quantum sensing applications.

Imaging performance is pushed further by the ASIX analog spectral imager for X-rays, introduced as a technology demonstrator targeting simultaneous high spatial and energy resolution. By adopting an ultra-low-noise, fully analog, asynchronous readout architecture, ASIX addresses charge-sharing limitations inherent to small-pixel devices and targets demanding applications in synchrotron science, material studies, and soft X-ray astrophysics.

Radiation effects at the biological scale are addressed through contributions on microdosimetry. One review focuses on miniaturized tissue-equivalent proportional counters developed at INFN National Laboratories of Legnaro (LNL), optimized for stable operation in hadron therapy environments. These detectors provide microdosimetric quantities essential for linking physical dose to biological effectiveness.

Finally, the activities of INFN within the Medipix4 international collaboration are summarized, highlighting the characterization of advanced hybrid pixel detectors based on Timepix4 and Medipix4 ASICs. These efforts contribute to the development of next-generation pixelated detectors featuring enhanced spatial, temporal, and energy resolution across a broad range of applications.

Together, the contributions collected in this Research Topic reflect the diversity, coherence, and maturity of CSN5 activities. They emphasize the role of particle and radiation sensors as key enabling technologies at the interface between fundamental research and real-world applications, fully aligned with the interdisciplinary mission of Frontiers in Sensors.

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Footnotes

Edited and reviewed by: Dermot Diamond, Dublin City University, Ireland