arXiv subjects

C. H. Zepeda Fernández

Publications and source records attributed to C. H. Zepeda Fernández.

9 recordsLinked to original sources

arXiv2026

Geant4 Simulation of an X-ray Beam Monitoring Detector based on plastic scintillators

Beam monitoring detectors play an important role in experimental control and radiological protection by enabling the real-time characterization of particle and photon beams. They provide information on beam intensity, position, and scattering, helping to ensure measurement accuracy, protect sensitive detectors, and quantify stray radiation in the surrounding environment. In this work, a Geant4 simulation was developed to investigate the performance of an X-ray beam monitoring detector (BMD) composed of six hexagonal BC404 plastic scintillators arranged to provide high granularity, using a reflector with a realistic reflectivity of 93\%. Under the simulation conditions considered in this study, the detector exhibited an intrinsic time resolution of 100.8 $\pm$ 2.0~ps. The results indicated that only about 10\% of the incident photons interacted with the detector, suggesting that the proposed design could be used for beam characterization while minimally perturbing the primary beam. In addition, the X-ray multiplicity decreased with distance according to an inverse-square dependence. A backscatter study performed using a water phantom showed that approximately 6\% of the incident beam was detected as scattered radiation. These results suggest that the proposed detector may be a useful tool for X-ray beam characterization and for studies related to scatter radiation and radiological protection. Further experimental validation is required to confirm these findings.

physics.med-ph↗

arXiv2025

Solar irradiance statistical analysis in Mexico City from 2018 to 2021

Solar radiation is made up of three components of electromagnetic waves: infrared, visible and ultraviolet. The infrared component is the cause of thermal energy, the visible spectrum allows to see through the eyes and the ultraviolet component is the most energetic and damaging. Solar radiation has several benefits, such as helping to synthesize vitamin D in the skin, favors blood circulation, among others benefits for the human body. In the Earth, it is the main source of energy for agriculture, also used as an alternative source of energy to hydrocarbons, through solar cells. The solar irradiance represents the surface power density with units W/m$^2$ in SI. Too much exposure can cause damage and an increase in value over the time can be can be also damaging. In this work it was used an open data base provided by Secretaría del Medio Ambiente, from which a statistical analysis was performed of the solar irradiance values measured at various meteorological stations in Mexico City and the so-called metropolitan area, from 2018 to 2021. This analysis was carried out per years, months and days. From the solar irradiance values distributions, it was obtained the averages, maximums and means were it was found there was no variation in the solar irradiance values over this period of years.

physics.space-ph↗

arXiv2023

Characterization in Geant4 of different PET configurations

Positron Emission Tomography (PET) is a Nuclear Medicine technique that creates images that allow the study of metabolic activity and organ function using radiopharmaceuticals. Continuous improvement of scintillation detectors for radiation in PET as well as improvement in electronic detectors (e.g., SiPMs) and signal processing, makes the field of PET a fast and changing environment. If industry desires to build new systems implementing these technological improvements, it is of its interest to develop modelling strategies that can provide information on how to build them, reducing time and material costs. Bearing this in mind three different PET configurations, were simulated in Geant4, to determine which one presented the best performance according to quality parameters such as spatial resolution (SR), coincident time resolution (CTR) and acceptance value (A). This was done with three different (in size) pairs of LYSO crystals + SiPM detectors. It was found that the 2 Modules system presented worst results than the two Ring detector configurations. Between the Ring configurations the first was marginally better than the second.

physics.ins-det↗

arXiv2023

Differential cross section for elastic collision, first exited state and ionization of water molecule

The radiolysis of water is an important study in microdosimetry, one of the resulting and important molecules in this study is the $OH^-$. Theoretical quantum mechanics calculations are used to obtain the differential cross section for the elastic collision, first excited state and ionization of water molecule. For the ionization case, obtaining $OH^-$ is studied. As incident particles are considered electrons and protons, independently for each phenomena previously mentioned. The differential cross section was obtained by the amplitude function. The water molecule model used to calculations consisted by the two protons of the hydrogen atom that make up the water molecule and the structure-less and doubly charged oxygen. For the proton incident particle case, the identical particle analysis was used. The results show the angular dependence and therefore the interference phenomenon between the incident wave and the deflected wave

physics.chem-ph↗

arXiv2023

Trigger efficiencies of a proposed beam monitoring detector (BeBe) for p+p collisions at NICA energies

The Multipurpose Detector (MPD) consists of a typical array of sub-detectors to study the nuclear matter originating from the collisions of beams provided by the Nuclotron-based Ion Collider fAcility (NICA). A beam monitoring detector~(BeBe) is proposed for stage 2 of MPD to increase the trigger capabilities. BeBe is constituted of two plastic scintillator disks segmented in 80 cells $\pm~2~m$ away from the interaction point of MPD. Laboratory measurements to obtain the energy resolution of an individual BeBe cell prototype are presented. It is shown that an energy resolution of $22\pm6\%$ can be obtained. Based on Monte Carlo simulations, the trigger efficiencies of the BeBe are presented for p+p collisions at 11~GeV considering a threshold in the energy loss of the charged particles reaching the detector.

hep-ex↗

arXiv2022

Performance of BeBe, a proposed dedicated beam-beam monitoring detector for the MPD-NICA experiment at JINR

The Multipurpose Detector (MPD) is an experimental array, currently under construction, designed to study the nuclear matter created during the collisions that will be provided by the Nuclotron-based Ion Collider fAcility (NICA) at JINR. The MPD-NICA experiment consists of a typical array of particle detectors as those used to study heavy-ion collisions at LHC and RHIC. To increase the trigger capabilities of MPD for stage 2 of NICA operation, a detector conformed by two arrays of 80 plastic scintillator cells each located symmetrically at opposite sides of the interaction point of MPD is proposed (BeBe). Based on Monte Carlo simulations, a discussion of the potential physics performance of BeBe detector is given for triggering tasks and for the resolution in the determination of the event plane reaction and the centrality of the collisions at NICA. Also, laboratory measurements to estimate the time resolution of individual BeBe cells prototypes are presented. It is shown that a time resolution between 0.65 and 1.48 ns can be reached depending on the number of photosensors employed to collect the scintillation photons. The BeBe detector will be complementary to FFD and FHCAL forward detectors.

physics.ins-det↗

arXiv2020

The conceptual design of the miniBeBe detector proposed for NICA-MPD

We present the conceptual design for the miniBeBe detector proposed to be installed as a level-0 trigger for the TOF of the NICA-MPD. We discuss the design and the geometrical array of its sensitive parts, the read-out electronics as well as the mechanical support that is envisioned. We also present simulation results for p + p and Bi + Bi collisions to study its capabilities as a function of multiplicity both as a level-0 trigger for the TOF, as well as to serve as a beam-gas interaction veto and to locate the beam-beam interaction vertex.

physics.ins-det↗

arXiv2019

A beam-beam monitoring detector for the MPD experiment at NICA

The Multi-Purpose Detector (MPD) is to be installed at the Nuclotron Ion Collider fAcility (NICA) of the Joint Institute for Nuclear Research (JINR). Its main goal is to study the phase diagram of the strongly interacting matter produced in heavy-ion collisions. These studies, while providing insight into the physics of heavy-ion collisions, are relevant for improving our understanding of the evolution of the early Universe and the formation of neutron stars. In order to extend the MPD trigger capabilities, we propose to include a high granularity beam-beam monitoring detector (BE-BE) to provide a level-0 trigger signal with an expected time resolution of 30 ps. This new detector will improve the determination of the reaction plane by the MPD experiment, a key measurement for flow studies that provides physics insight into the early stages of the reaction. In this work, we use simulated Au+Au collisions at NICA energies to show the potential of such a detector to determine the event plane resolution, providing further redundancy to the detectors originally considered for this purpose namely, the Fast Forward Detector (FFD) and the Hadron Calorimeter (HCAL). We also show our results for the time resolution studies of two prototype cells carried out at the T10 beam line at the CERN PS complex.

physics.ins-det↗

arXiv2019

Time resolution studies for scintillating plastics coupled to silicon photo-multipliers

We present results for time resolution studies performed on three different scintillating plastics and two silicon photo-multipliers. These studies are intended to determine whether scintillating plastic/silicon photo-multiplier systems can be employed to provide a fast trigger signal for NICA's Multi Purpose Detector (MPD). Our results show that such a system made of cells with transverse dimensions of order of a few cm, coupled to silicon photo-multipliers, provides a time resolution of about 50 ps, which can be even further improved to attain the MPD trigger requirements of 20 ps.

physics.ins-det↗