María Dolores Pérez

arXiv2026

Ultraviolet plastic scintillators based on naphthalene-doped polystyrene and polyvinyltoluene

This work reports the fabrication and optical characterization of ultraviolet-emitting plastic scintillators based on polystyrene [-(CH2-CH(C6H5))n-] and polyvinyltoluene [-(CH2-CH(C6H4CH3))n-] doped with different concentrations of naphthalene (Naph). Photoluminescence (PL) measurements show that Naph incorporation enhances the emission intensity, inducing a red shift in the emission wavelength of the polystyrene (PS), while Naph-doped polyvinyltoluene (PVT) exhibits a bimodal emission with peaks around 335 and 350 nm. Time-resolved photoluminescence (TRPL) reveals fast decay components for the undoped matrices and a dominant slow component of approximately 87 ns in the doped samples. Scintillation light yield measurements indicate moderate performance for the undoped polymers and a significant enhancement upon Naph doping. Proton irradiation experiments reveal a reduction in light yield for all samples, with Naph-doped PVT retaining a larger fraction of its initial light yield compared to PS-based scintillators, indicating improved radiation tolerance. Overall, these results demonstrate the effectiveness of Naph as a UV emission enhancer and highlight Naph-doped PVT as a promising candidate for compact and radiation-resistant scintillation detectors.

cond-mat.mtrl-sci↗

arXiv2022

A multilayer network model of Covid-19: implications in public health policy in Costa Rica

Successful partnerships between researchers, experts and public health authorities has been critical to navigate the challenges of the Covid-19 pandemic worldwide. In Costa Rica, we constructed a multilayer network model that incorporates a diverse contact structure for each individual (node). The different layers which constitute the individual's contact structure include: family, friends, and sporadic interactions. Different scenarios were constructed to forecast and have a better understanding of the possible routes of the pandemic in the country, given the information that was available at the time and the different measures implemented by the health authorities of the country. Strong collaboration within our diverse team allowed using the model to tailor advice on contingency measures to health authorities. The model helped develop informed strategies to prepare the public health system in Costa Rica. The development, evolution and applications of a multilayer network model of Covid-19 in the adoption of sanitary measures in Costa Rica has been an example of the potential of such partnerships.

physics.soc-ph↗