Nome
Novel LUMInescent passive DOS

Código
2023.15783.PEX

Entidade Beneficiária

LIP - Laboratório de Instrumentação e Física Experimental de Partículas

Sumário do Projecto

Radiation dose measurement is of key importance in fundamental physics, medical diagnostics and treatment, personal dosimetry, space travel, energy production, nuclear applications, radiopharmaceutical and food industries. The main research interest of the team is on the study of the intricate effect of radiation at the micro-scale cell-level which is pivotal for advancing cancer treatment strategies. To describe in detail the particle interactions and secondary particle production, there is a need for new detectors that surpass the performance of existing dosimeters such as ionization chambers (Legrand, 2012), microdiamond (Zahradnik, 2018; Loto, 2021) and silicon (Guardiola, 2020) based dosimeters.The LUMIDOS project proposes to develop a new set of cutting-edge passive detectors by studying alternative dopants for alumina single crystals to produce improved fluorescent nuclear tracking detectors (FNTD). The crystal growth will be the C2TN main responsibility, while the characterization of undoped and doped crystals are shared between C2TN and LIP. For specific tasks, other institutions (i.e., PSI and DKFZ) will consult. Monte Carlo (MC) simulations of radiation tracks in the crystals will be developed by LIP.The current known formula for FNTD with C,Mg doping (Akselrod, 2006; Akselrod, 2011) shows limitations regarding sensitivity to electrons, neutrons and photons. The research strategy will be to dope the crystal with carbon and a transition metal. The most promising combinations, according to the literature, will be investigated. For example, during ultra-high dose radiation therapy (FLASH) with protons, the secondary components of the radiation field should be quite different as compared to other methods, such as Pencil Beam Scanning (PBS) or Broad Beam Scattering (BBS). The groundbreaking nature of FLASH therapy requires new developments in dosimetry to access a more detailed description of energy distribution inside the cells and the contribution from the different secondary particles.For the corundum crystals growth the flux method (Kane, 1982), a low temperature procedure, is going to be used. The flux method ensures precise control over crystal morphology and purity, enhancing the overall performance of the detectors. The LUMIDOS project starts with the optimization of the crystal growth procedure to increase crystal size, produce high purity crystals and reach the desired morphological and optical features. The parametrization of the dosimetric properties will follow, studying the correlations of doping agents' concentrations and types. Characterization techniques including TL/OSL and RPL characterization, along with XRD, SEM-EDS, PIXE, PIGE and XRF, will be employed to evaluate the luminescent and structural properties of the crystals, combining the experience of C2TN, LIP and FCT/UNL.The produced doped crystals will be prepared as laminated samples to have reference surfaces for irradiation. This step will be performed at the Department of Geology of FCUL. Subsequently, the doped crystals will undergo irradiation using radioactive sources (Am-241) and low-energy particle beams (C2TN) available in Portugal. These dosimeters are read using widefield and confocal laser scan microscopy (CLSM) (Walsh, 2020).Access to this specific equipment is provided through the microscopy service available at FCUL. Reaching this stage and observing the expected defects and tracking patterns (Askelrod, 2011) it is concluded that the newly produced crystals have dosimetric characteristics. Monte-Carlo (MC) simulations using TOPAS/Geant4 will be used for quality evaluation of the experimental measurements. The simulations will allow for a better understanding of the micro- and nanodosimetric quantities, providing valuable calibration for the experimental data obtained from the microscopy measurements. The reset after a thermal annealing will also be evaluated. In a more advanced stage, irradiations with a neutron source (AmBe) and clinical hadron beams are foreseen, at the Paul Sherrer Institute (PSI, Switzerland) and the German Center for Cancer Treatment (DKFZ, Heidelberg).The LUMIDOS project is envisioned as being an opportunity to deliver outcomes that will enhance the technological capabilities of all research centers involved. The improved features of these FNTDs pave the way for more accurate and reliable data collection in a field where precision is paramount. As a result, this research contributes to the ongoing efforts to develop sophisticated radiation detection technologies with widespread implications for scientific research and practical applications.

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Suporte sob

Reforçar a investigação, o desenvolvimento tecnológico e a inovação

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