DLight: New Plastic Scintillators for Future Light-based Detectors
LIP - Laboratório de Instrumentação e Física Experimental de Partículas
This project explores promising novelties on plastic scintillating materials to launch the basis for a comprehensive R&D program on the production of radiation-hard scintillators. We target opportunities on the construction of future experiments in High Energy Physics (HEP) and applications to nuclear imagiology in the healthcare field, both expected to evolve into future partnerships with the industry. Organic scintillators and wavelength-shifters (WLS) are a basis for particle/radiation detectors used in many Nuclear Physics applications. Conventionally, they consist of polymers doped with luminophores that emit ultra-violet (UV) light upon excitation by ionising radiation. WLS convert UV into visible light, more adapted to the efficiency of photodetectors. Due to low cost/weight and malleability, plastic scintillators are common in nuclear safety monitors or radiation dosimetry. In Particle and Nuclear Physics research, they are fundamental for light-based detectors at uttermost large scales. Recent developments in plastic scintillators and WLS optical materials were introduced. The industry is developing new low-cost dosimeters based on PET (Polyethylene Terephthalate) and PEN (Polyethylene Naphthalate) from an initial idea of recycling water bottles, cutting production cost by 90%. One of the advantages is that PET and PEN emit bluish light without the addition of WLS dopants. While promising, these developments have not yet been fully exploited, for instance concerning the usage of PET/PEN mixtures, the combination of dopants and radiation resistance. This project consists of exploratory R&D on new scintillating materials based on PET and PEN blends aiming at selecting the material and manufacturing formulas with the best luminous signal based on optical characterisation of the produced samples. The addition of WLS dopants to the polymer mixture may be explored. To this end, we established a collaboration between LIP’s Laboratory of Optics and Scintillator Materials (LOMaC) and the Institute for Polymers and Composites (IPC) of the University of Minho. LIP members are HEP experimentalists, part of the ATLAS collaboration at CERN, and the IPC members are experts in the Science and Engineering of Polymers and Composites. The LIP team contributed to the R&D and construction of the Tile Hadronic Calorimeter of ATLAS (TileCal), which is scintillator-based, and has long-term expertise in the study of WLS/scintillating plates and optical fibres, including radiations hardness. IPC has competence in the formulation, compounding, polymer blending and modification via reactive extrusion, processing of both thermoplastic and thermosetting systems, and macromolecular, morphological and mechanical characterisation. IPC and LOMaC have unique capabilities in Portugal to carry R&D on plastic scintillators and collaborated successfully in the past in the development of high-quality scintillating tiles and a scalable production line, which was the backup solution for TileCal construction. Optical instrumentation of calorimeters is a topic of expertise at LIP and strategic investment for the laboratory. The 2020 European Strategy for Future Accelerators recommended a 100 km Future Circular Collider (FCC) to be built at CERN and the plans for the next generation experiments started. The major requirements for detector R&D are long-term operation under harsh radiation and extreme detection rates and noise environment. Light-based detectors must provide maximal light yield, more radiation hardness and faster response. Here, PET/PEN offer a priori competitive light output and a low percentage of natural radioactivity while being cheap options for detectors with a considerable material budget. The 2020 Portuguese Roadmap of Research Infrastructures inscribes a Network for Proton Therapy and Advanced Technologies for Cancer Prevention and Treatment (ProtoTera), of which LIP is a founding member and main provider of expertise in dosimetry and instrumentation for biomedical applications. Here, the low-cost nature of PET/PEN would facilitate larger tomography chambers useful in the monitoring of patients' response to radiotherapy. The project will start with the production and mechanical characterisation of small samples of PET/PEN blends at varied proportions at IPC. These will be tested at LOMaC for the scintillation properties - light output and emission/transmission spectra. Achieving this milestone, we will produce larger scintillating plates from the blends with the best scintillation properties. Then, optical characterisation follows, with measurements of light attenuation, response uniformity and scintillation pulse decay time. Moreover, one of the tasks consists of the development and construction of a coincidence spectrometer to measure the absolute light yield of the scintillators in terms of the number of emitted photons per MeV of deposited energy, the unique missing equipment in the lab needed for our project.
Reforçar a investigação, o desenvolvimento tecnológico e a inovação
Region of Intervention
Versão Extensa: Este trabalho é financiado por fundos nacionais através da FCT - Fundação para a Ciência e a Tecnologia, I.P., no âmbito do projeto EXPL/EME-NUC/1311/2021
Versão Resumida: OE,FCT-Portugal, EXPL/EME-NUC/1311/2021