J. Ureña | Searcharxiv

arXiv2026

Measurement of the X-ARAPUCA's Absolute Photon Detection Efficiency for the Deep Underground Neutrino Experiment's Vertical Drift Far Detector

The DUNE experiment will implement a photon detection system composed of X-ARAPUCA (XA) devices. These trap incoming VUV photons by internal reflection in a wavelength shifter light guide to be collected onto silicon photomultiplier arrays, sensitive to visible light. In the baseline design, dichroic filters are used to prevent photons from escaping. The configuration proposed for DUNE's Vertical Drift (VD) module has been characterised in liquid argon for the first time using dedicated cryogenic setups developed at CIEMAT and INFN Naples. Additionally, several alternative configurations, based on the design optimisation studies of an R&D campaign, have been evaluated. The results show an efficiency of up to 4.5$\pm$4~% at 4.5~V overvoltage, representing a significant improvement over previous XA implementations. Most notably, configurations without dichroic filters show an improvement of up to 18~%, attributed to transmittance losses in the dichroic filters.

physics.ins-det↗

arXiv2024

Advanced monitoring of rail breakage in double-track railway lines by means of PCA techniques

This work describes a classifier designed to identify rail breakages in double-track railway lines, completing the electronic equipment carried out by authors. The main objective of this proposal is to guarantee the integrity of tracks before the railway traffic starts working. In addition, it facilitates maintenance tasks providing information about possible breakages. The detection of breakages is based on the analysis of eight currents provided by the electronic equipment, one per rail, at the ends of the section (emitting and receiving nodes). The imbalance that occurs among the value of these currents implies that there is at least a breakage in the track section under analysis. This analysis is conducted according to three phases. The first one identifies whether there is a breakage, and, in that case, the damaged track is identified. The second phase provides information about which rail is broken (internal, external or both of them) in the previously identified track. Finally, if there is only one breakage, the third phase estimates its most likely zone along the track section. This situation is considered as a classification problem, and solved by means of the Principal Component Analysis technique. This means that a significant number of measurements is required for every breakage pattern (types of breakages) to be considered. Due to the difficulty of having real data, the proposal has been validated using an 8km-long double-track hardware simulator specially designed by the authors, with specific localizations for breakages.

eess.SP↗