Publications by authors named "Teodoro RIvera Montalvo"

Phosphors composed of GdREAlO (0≤x ≤ 5 RE = Dy or Pr) stoichiometries were synthesized using the reverse coprecipitation pathway. The thermoluminescent responses of all phosphors were studied under beta radiation exposure. Doping the gadolinium aluminate host improved the thermoluminescent response of the phosphors, with the phosphors composed of GdDyAlO and GdPrAlO being the most sensitive.

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We use 395 nm ultraviolet radiation to excite the matrix of barium hafnate doped with europium ions to develop an optical temperature sensor. Luminescent analysis as a function of temperature was performed in the physiological range. The Emission spectra showed significant variations in luminescent intensity at all transitions, obtaining a relative sensitivity of 1574.

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The suitable choice of an activator and host combination is essential for synthesizing very sensitive thermoluminescence phosphors. In addition, conspicuous synthesis variables must be optimized to achieve the maximal response. The research presented herein shows that the most recommendable conditions to improve the thermoluminescence response of beta irradiated GdEuAlO phosphors were: x = 0.

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Thermoluminescent dosimetry, analytical techniques and Monte Carlo calculations were used to estimate the dose of neutron radiation in a treatment room with a linear electron accelerator of 18MV. Measurements were carried out through neutron ambient dose monitors which include pairs of thermoluminescent dosimeters TLD 600 (LiF: Mg, Ti) and TLD 700 (LiF: Mg, Ti), which were placed inside a paraffin spheres. The measurements has allowed to use NCRP 151 equations, these expressions are useful to find relevant dosimetric quantities.

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Using Monte Carlo methods a BOMAB phantom inside a treatment hall with a brain tumor nearby the pituitary gland was treated with photons produced by a Varian 6MV linac. The photon spectrum and the absorbed dose were calculated in the tumor, pituitary gland and the head. The treatment beam was collimated to illuminate only the tumor volume; however photons were noticed in the gland.

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Most of the existing methods for obtaining the frequency factors make use of the trap depth (activation energy) making some assumptions about the order of the kinetics. This causes inconsistencies in the reported values of trapping parameters due that the values of the activation energy obtained by different methods differ appreciably among them. Then, it is necessary to use a method independent of the trap depth making use of the isothermal luminescence decay (ILD) method.

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