Revista de Ciencia y Tecnología

Diamond Pin Thermal Neutron Detectors

2023-10-04T13:39:51-06:00

Diamond PIN diodes with an approximately 5-μm thick i-layer and coated with a thin boron nitride (BN) layer have been tested with a thermal neutron beam flux of 4.4×106 n/s/cm2. Pulse height spectra showed features associated with α and 7 Li fission products, consistent with the thickness of the BN layer. An irradiation test with a 1 MeV neutron equivalent fluence of 1015 n/cm2 showed no significant alteration in the count rate of the tested detector.

Temperature Effects on Nuclear Masses, Reactions and Abundances

2023-10-04T13:31:35-06:00

Las reacciones nucleares en ambientes astrofísicos dependen de las masas, las energías y la temperatura del entorno. Al observar la relación entre las energías de excitación de los núcleos y la temperatura del ambiente en el que se encuentran, es razonable considerar la dependencia de la temperatura en las masas nucleares en entornos astrofísicos. En este trabajo, se incluyen los efectos de la temperatura en las masas nucleares y se examina cómo las tasas de reacción nuclear relevantes cambian en el contexto de la nucleosíntesis del Big Bang.

Validation of a GEANT4 based Monte Carlo code for voxelized geometries for patient-oriented mammography dosimetry

2023-06-13T13:59:58-06:00

This work presents a preliminary validation of a Monte Carlo radiation transport code capable of simulating radiation transport on voxelized structures. Field size and depth dose were measured at Physikalisch-Technische Bundesanstalt (PTB) Braunschweig for mammography tungsten spectra of 30 kVp and 50kVp. Four different collimators were used to vary the field size between 0.94 cm and 4.74 cm of aperture radius. Depth dose was measured between 0 cm and 2 cm depth using a PTW PMMA phantom and two PTW ion chambers. Monte Carlo simulations were performed using the Geant4 toolkit (EM standard physics). Maximum relative difference in field size effect between experiment and simulation was 2.1%. In the case of the depth-dose study, it was 5.6%. The simulations used in this study have been shown to provide accurate estimations of quantities relevant to the calculation of dosimetric quantities.

Temperature-Dependent Cluster Decay Half-Lives

2023-10-04T14:23:55-06:00

Temperature-dependent cluster decay half-lives are investigated based on the double folding model (DFM). The temperature dependence of the interaction potential is introduced through the charge and matter density distributions of the interacting nuclei, and the half-lives are calculated within a preformed cluster model. Subsequently, the temperature-dependent universal decay law (UDL) is fitted using the half-lives calculated with the double folding model.

Effects Of Temperature In Alpha Decay

2023-10-04T13:17:30-06:00

One of the processes relevant in a nucleosynthesis calculation is the alpha decay (a-decay) of heavy nuclei. In this work, the alpha decay process is investigated in an astrophysical environment by introducing temperature dependence in the calculation of half-lives. By using a simple model based on the semiclassical treatment of the alpha decay process, the half-lives are evaluated by considering an alpha particle, which tunnels through the Coulomb barrier generated by its interaction with the daughter nucleus. We find the temperature dependent half-lives for several isotopes and compare them with the results obtained in a previous work. It is concluded that including temperature leads to a reduction in alpha decay half-lives. However, the magnitude of the reduction depends on the approach used.