Beta Particle Irradiation Research Articles

Novel materials for radiation sensing in radiotherapy treatments: Development of luminescent YVO4:Eu3+ polymer-based nanocomposites

This scientific work explores the development of luminescent nanocomposite materials for radiation sensors in Fiber Optic Dosimetry (FOD). The study emphasizes the use of YVO4:Eu3+ as a scintillator material due to its high luminescent efficiency. However, the challenge arises from its higher effective atomic number compared to soft tissue. To address this issue, the work explores the dispersion of YVO4:Eu3+ as nanoparticles (NPs) in a biocompatible polymeric matrix, specifically considering poly(methyl methacrylate) (PMMA) and poly(ethylene glycol) dimethacrylate (PEGDMA). Both PMMA/YVO4:Eu3+@TMSPM and PEGDMA/YVO4:Eu3+@TMSPM formulations were synthesized with minimal impact on the glass transition temperatures of the polymers. Under UV and beta particle excitation, these formulations exhibit emission spectra characteristic of Eu3+ f-f transitions. The decay times of the main emission peak at 620 nm were 615 μs, 584 μs, and 567 μs for the NPs, PEGDMA- and PMMA-based polymeric nanocomposites (PNCs), respectively. These decay times fall within the range suitable for scintillators in LINAC pulsed radiation facilities. Also, PEGDMA- and PMMA-based PNCs with varying contents of YVO4:Eu3+ NPs showed radioluminescence spectra under beta particle irradiation. This work demonstrates the feasibility of developing PEGDMA- and PMMA-based PNCs containing dispersed YVO4:Eu3+ NPs for their application as scintillators in radiotherapy dosimetry.

Thermally stimulated luminescence of BaZrO3:Eu3+ nanopowders for dosimetric applications

In this study, we synthesized BaZrO3 nanoparticles (NPs) by incorporating Eu3+ ions at various concentrations (1–15 mol%) using hydrothermal synthesis. We confirmed the cubic crystalline structure of the samples and determined an average crystallite size of 13.15 nm through X-ray diffraction (XRD) analysis. High-resolution transmission electron microscopy revealed spherical nanoparticles with an approximate diameter of 55 nm in the BaZrO3:Eu3+ sample. Before conducting thermoluminescence (TL) measurements, the samples underwent thermal treatment at 350 °C. The TL glow curve of the phosphor, when exposed to beta irradiation, exhibited two prominent peaks with maxima at approximately 127 and 295 °C, with a heating rate of 10 °C/s. We identified the optimal doping concentration for BaZrO3:Eu3+ as 5 mol%. The TL response demonstrated excellent linearity within the 1–39 Gy range when subjected to beta particle irradiation. We also observed noteworthy repeatability in the integrated TL response across 10 irradiation-TL readout cycles, with less than 2 % variations. Over 21 days, the signal faded to approximately 50 %. Furthermore, we employed general-order kinetics, the TLAnal software, and TM-Tstop experiments to deconvolute the TL glow curve of BaZrO3:Eu3+. This analysis revealed at least 5 TL peaks, each exhibiting a first-order tendency. Our findings indicate the potential of BaZrO3:Eu3+ as a promising dosimeter for ionizing radiation applications.

Persistent luminescence of commercial TLD-100 dosimeter: Using shallow traps for radiation dosimetry

This work reports the persistent luminescence (PersL) properties of the commercial LiF:Mg,Ti (TLD-100) dosimeter and its performance in dosimetry applications. The thermoluminescence (TL) glow curve of the TLD-100 exhibits a peak at 96 °C that rapidly vanishes at room temperature, enabling the PersL phenomenon. The TLD-100 was exposed to beta particle irradiation within in the range of 0.22–32 Gy. The resulting PersL intensity was measured and found to increase as the irradiation dose increased. Notably, there was no saturation of the PersL intensity within this dose range with linear dependence from 0.55 to up 32 Gy. The TLD-100 showed good repeatability with a deviation of 0.1% after seven irradiation-readout cycles for twenty irradiations. The calculated lower detection limit was 2 mGy. Our results indicate that the TLD-100 can be used as a PersL and TL dosimeter for dosimetry applications, with the advantages of fast post-irradiation measurements.

Unravelling the impact of unusual heating rate, dose-response and trap parameters on the thermoluminescence of Sm3+ activated GdAl3(BO3)4 phosphors exposed to beta particle irradiation

The thermoluminescence of GdAl3(BO3)4 (GAB) doped with various concentrations of Sm3+ (i.e. from 0.5 to 7 wt%), prepared by gel combustion, was studied. TL glow peaks at 78 °C and 225 °C are observed. The intensity of the glow peak at 225 °C increased with a faster heating rate. To gain insight into the trap activation energies, the methods of Hoogenstraaten and Booth-Bohun-Parfianovitch were used, where the calculated activation energies are 0.57 eV and 0.60 eV for Peak I and 1.69 eV and 1.71 eV for Peak II respectively. The dose-response of GAB:0.5 wt%Sm3+ demonstrates robust linearity up to 40 Gy, with a strong correlation coefficient of 0.999. Both TM-Tstop combined with the Initial Rise (IR) and Computerized Glow Curve Deconvolution (CGCD) techniques were employed, which revealed six overlapping glow peaks beneath the main peaks. Additionally, the results suggest that the TL signal can be efficiently exploited for radiation dosimetry applications.

Persistent luminescence dosimetry performance of solid state synthesized BaZrO3 phosphors

This work reports for the first time on the thermoluminescence (TL) and persistent luminescence (PLu) characterization of BaZrO3 synthesized through solid state reaction. X-Ray diffraction confirmed the crystalline structure of the synthesized phosphors. The characteristic glow curves of the synthesized samples exhibit TL maxima located at 85 and 165 °C, whose fading after radiation exposure gives rise to intense PLu. PLu decay curves were recorded after beta particle irradiation in the dose range from 1.0 up to 1024 Gy. Both TL and PLu exhibit remarkable reproducibility. The integrated persistent luminescence (IPLu) as a function of the irradiation dose exhibits a linear dependence in the 1.0–16 Gy dose range, followed by a sublinear behavior from 16 to 128 Gy. From the experimental evidence here presented, it is concluded that solid state synthesized BaZrO3 is an interesting phosphor material to be implemented as a PLu-based detector and dosimeter.

Persistent luminescence of ZrO2:Tb3+ after beta particle irradiation for dosimetry applications

In this work, we report the Persistent Luminescence (PLUM) of ZrO2:Tb3+ samples synthesized by a conventional solid-state reaction and its performance in radiation dosimetry. X-ray diffraction shows the formation of the monoclinic phase of ZrO2 and the doping of the samples with Tb3+ ions and a mixture of Tb2O3. The ZrO2:Tb3+ 1% sample was exposed to beta particle irradiation in a dose range from 0.5 to 256 Gy. Immediately after removing the beta particle source, the PLUM response was measured for 600 s. The integrated area of the PLUM decay curves shows a sublinear dependence in the dose range from 0.5 to 64 Gy. The TL glow curve of the ZrO2:Tb3+ 1% sample showed two maxima at 79 and 150 °C after beta particle irradiation, suggesting that the trapping states associated with the maximum at 79 °C are responsible for the PLUM at room temperature. Computational deconvolution showed that the maximum at 79 °C consisted of two traps with first-order kinetics. The results suggest that the ZrO2:Tb3+ 1% sample has potential applications as a dosimeter for beta particle irradiation.

Thermoluminescence radiation dosimetry in Sonoran zeolite exposed to beta particle irradiation

In this work, we report the thermoluminescence (TL) response of a zeolite (Chabazite-Ca) from Divisaderos Sonora region northwestern Mexico and its performance in dosimetry applications. X-ray diffraction, scanning electron microscopy, and Energy Dispersive X-ray Spectroscopy were performed to obtain the structural, morphological, and elemental composition of the prepared zeolite samples. Zeolite samples were exposed to beta particle irradiation in the dose range from 5 to 7017 Gy. The TL glow curves of zeolite display a broad curve shape indicating the overlap of several TL glow peaks. The TL glow curve shows a maximum emission located at ∼174 °C and a prominent shoulder at 280 °C. The TL signal increases as the dose increase, keeping a linear dependence from 5 to up 690 Gy. A remarkable reproducibility of integrated TL response in 10 irradiation- TL readout cycles was observed, indicating zeolite samples are reusable. The fading signal is around ∼50 % in 3 days. The reported results suggest that Sonoran zeolites have potential applications as detectors and dosimeters for ionizing radiation.

Beta radiation excited thermoluminescence of solid-state synthesized SrZrO3 phosphors

In this work, we report on the solid-state reaction synthesis of SrZrO3 phosphors, and their beta particle irradiation excited thermoluminescence (TL) characterization. X-ray diffraction data confirmed the obtention of the orthorhombic phase of SrZrO3. Through computational glow curve deconvolution, the whole glow curve was resolved into six individual first order kinetics peaks. This is the first report concerning the usefulness of SrZrO3 as TL dosimeter. The synthesized phosphors exhibit TL emission from below 100 °C up to above 300 °C, being the most intense TL between 200 and 300 °C, as well as a remarkable reproducibility of the TL response in repeated irradiation-TL readout cycles.

Thermoluminescence study and evaluation of trapping parameters of samarium doped barium silicate phosphor

ABSTRACT We report the detailed analysis of thermoluminescence (TL) glow curves and the evaluation of kinetic parameters of Sm3+-incorporated BaSi2O5.The effect of various heating rates on TL kinetics and glow peak temperatures of Sm3+-doped BaSi2O5 phosphors exposed to beta particle irradiation at room temperature are investigated. The glow curve of the phosphor exposed to β-irradiation consists of two main peaks with maxima at about 91°C and 193°C and exhibits good linearity between 1 and 10 Gy. The activation energies and frequency factors of trap centers involved in the TL emission were calculated from the TL glow curve of the sample by means of variable heating rate (VHR), repeated initial rise (RIR), and computerized glow-curve deconvolution (CGCD). Analysis of the main dosimetric peak techniques indicate that activation energies (E) and pre-exponential factor (s) vary between 0.93 and 1.72 eV, 1010 and 1013 s−1. It is found that the temperature of the glow peaks shifts toward the higher temperatures and the TL intensity smoothly decreases as the heating rate increases. The behavior of the TL intensities and glow peak temperatures as a function of the heating rate are discussed with regards to thermal quenching.

Effects of microwave-assisted hydrothermal treatment and beta particles irradiation on the thermoluminescence and optically stimulated luminescence of SrMoO4 powders

SrMoO4 powders, produced by co-precipitation, are investigated employing thermoluminescence (TL) and optically stimulated luminescence (OSL). The effects of microwave-assisted hydrothermal (MAH) treatment, beta particle irradiation, and thermal treatment are studied to understand their role on defect density and location in the band-gap. The powder X-ray diffraction showed that the SrMoO4 powders crystallize in a tetragonal structure. The raman studies confirmed the presence of active vibration modes characteristic of molybdates, whereas the Fourier Transformed Infrared (FTIR) data exhibit the symmetric and asymmetric stretch vibrations. The trapping depth energies, determined from TL glow curves, range from 0.9 eV to 1.95 eV. The TL data show that the MAH treatment decreases the defect density and favors the formation of defects with lower activation energies. The residual TL signal shows the formation of shallower traps with a glow peak occurring at lower temperatures. The OSL emission only taken place for samples submitted to heating cycles and depends on the heating rate. These results indicate that shallow traps induced by thermal treatment are responsible for the OSL signal. The shape and intensity of the OSL curve depend on the number of heating cycles and on the heating rate, revealing that thermal treatment has a profound influence on this emission. The OSL signal for MAH-treated SrMoO4 samples subjected to thermal treatment increases linearly with beta irradiation dose. The results give insight that SrMoO4 phosphors may have potential applications in the design of a radiation sensor.

Synthesis and thermoluminescence characterization of self-agglomerating CaSO4 exposed to beta radiation

The synthesis and thermoluminescence (TL) characterization of self-agglomerating pellet-shaped CaSO4 phosphors, through a low cost and environmentally friendly method is reported. In order to investigate their TL features, some samples were exposed to beta particle irradiation in the dose range from 0.07 to 10 Gy. Characteristic TL glow curve consists of a single main maximum located at 216 °C, which is considered stable, hence, suitable for dosimetry applications. The dose-response was remarkable linear. Moreover, the lower detection limit was determined to be 6.0 μGy, and the relative TL sensitivity twice the one from the commercial TLD-100 dosimeter.

Thermoluminescence of ZnO:Na phosphors exposed to beta particle irradiation

In this work, the thermoluminescence (TL) characterization of pellet-shaped ZnO:Na phosphors synthesized through a controlled chemical reaction followed by thermal annealing at 900 °C in air is reported. X-Ray diffraction patterns reveal ZnO hexagonal zincite structure for the samples, some of which were exposed to beta particle irradiation in the dose range from 0.08 to 2048 Gy in order to study their TL features. The synthesized ZnO:Na samples are more than 200 times more sensitive than ZnO samples synthesized by the same method, and present a 0.02 (1/50) sensitivity relative to the TLD-100 dosimeter.

Afterglow dosimetry performance of beta particle irradiated lithium zirconate

In this work, we report for the very first time on the thermoluminescence (TL) and afterglow (AG) properties of Li2ZrO3. The ternary oxide Li2ZrO3 was synthesized by solid state reaction of a mixture of Li2CO3 and ZrO2 subjected to thermal annealing at 400°C for 2h and 1000°C during 24h in air. The characteristic glow curves of beta particle irradiated samples exhibit an intense TL emission located around 150°C. From the shape of the TL curve, a 0.4 form factor was determined, suggesting that first order kinetics processes are involved. The afterglow decay curves were recorded after exposure to beta particle irradiation in the dose range from 0.5 up to 2kGy. The AG integrated in the time interval from 510 to 600s after radiation exposure shows a linear dependence as a function of the irradiation dose from 0.5 up to 256Gy. A method is proposed to compute the lower detection limit and the AG sensitivity and applied to the studied phosphors. Structural and morphological characterization were carried out by X-ray diffraction and Scanning Electron Microscopy, respectively. From the results presented, it is concluded that the AG response of the synthesized Li2ZrO3 presents features suitable to develop radiation detectors and dosimeters.

Afterglow based detection and dosimetry of beta particle irradiated ZrO2

In this work, we report on the afterglow (AG) response characterization of commercially available ZrO2. Pellet shaped samples previously annealed in air at 1000°C during 24h were exposed to beta particle irradiation in the dose range from 0.5 up to 128Gy and their AG decay curves recorded during 600s after irradiation exposure. The characteristic glow curves of beta particle irradiated ZrO2 show two maxima located around 80°C and 150°C. The first one rapidly vanishes at room temperature, giving rise to AG. The integrated AG signal increases as dose increases from 0.5 to 128Gy, with a linear dependence from 0.5 up to ca. 32Gy. Excellent reproducibility of the AG response was observed in 10 irradiation – AG readout cycles, showing that the studied ZrO2 samples are reusable. The results here presented show that ZrO2 is a promising material for use as a radiation dosimeter based on the AG phenomenon.

Luminescence Imaging of Water During Irradiation of Beta Particles With Energy Lower Than Cerenkov-Light Threshold

The luminescence imaging of water during irradiation of beta particles with energy lower than the Cerenkov-light threshold has widely been considered impossible because such particles do not emit Cerenkov light. Contrary to this consensus, we found that luminescence imaging of water is in fact possible with such relatively low-energy beta particles. Beta particles from a 500-kBq 45Ca beta source (maximum energy: 257 keV) were irradiated to pure water, and the source’s luminescence images were acquired with a high-sensitivity, cooled charge-coupled device camera. We also conducted image acquisition for an acrylic plate and a plastic scintillator. The water’s luminescence image during beta particle irradiation became visualized after a 1200-s acquisition time. The luminescence intensity with the beta irradiation of water was 0.54 photons/MeV, and the luminescence intensity with that of the acrylic plate was 3.3 photons/MeV. Consequently, we have shown that luminescence imaging of water using beta particles with energy lower than the Cerenkov-light threshold is a promising new method for beta particle detection and distribution measurements.

Novel ZnO:Li phosphors for electronics and dosimetry applications

Novel ZnO:Li thermoluminescent phosphors were synthesized by a chemical method. Pellet-shaped samples were exposed to beta radiation to investigate their dosimetric capabilities. Some samples were exposed to beta particle irradiation for doses from 50 up to 1600 Gy, and it was found that the thermoluminescence response is a linear function in all over the dose range studied. The glow curve exhibits two maxima, centered at 385 and 507 K. The maximum located at 507 K shifts to lower temperatures as dose increases, indicating that second order kinetics thermoluminescence processes are involved. The results indicate that these new ZnO:Li phosphors are promising detectors and dosimeters for beta radiation.

Thermoluminescence Properties of Novel Self-Agglomerating CaSO4:Eu Phosphors Obtained by an Environmentally Friendly Method

In this work, we report the thermoluminescence (TL) properties of self-agglomerating CaSO4:Eu samples obtained by an environmentally friendly coprecipitation technique. No binding material is needed to form solid CaSO4:Eu samples. Samples exposed to beta particle irradiation exhibit a TL maximum at 473.15 K when a 5 K/s heating rate is used, they are two times more sensitive than the TLD-100 commercial dosimeter, and their lower detection limit was determined to be less than 0.69 mGy. The computerized glow curve deconvolution carried out fitting the residual glow curves from McKeever method revealed that the whole glow curve is composed of four individual TL peaks with intermediate-order kinetics. The main peak order kinetics is b = 1.48. This result agrees with that computed using Chen’s formula.

Analysis of Deep Level Defects in GaN p-i-n Diodes after Beta Particle Irradiation

The effect of beta particle irradiation (electron energy 0.54 MeV) on the electrical characteristics of GaN p-i-n diodes is investigated by current-voltage (I-V), capacitance-voltage (C-V) and deep-level transient spectroscopy (DLTS) measurements. The experimental studies show that, for the as-grown samples, three electron traps are found with activation energies ranging from 0.06 to 0.81 eV and concentrations ranging from 1.2 × 1014 to 3.6 × 1015 cm−3, together with one hole trap with energy depth of 0.83 eV and concentration of 8 × 1014 cm−3. It has been found that the irradiation has no effect on these intrinsic defects. The irradiation affected only a shallow donor level close to Ec [0.06 eV-0.18 eV] on the p-side of the p-i-n junction.

Synthesis and Thermoluminescence of a Spinel-Type Oxide Exposed to Beta-Particle Irradiation

ABSTRACTCurrently, the research team is systematically studying the oxide compounds present in the ternary system In2O3-TiO2-MgO in order to analyze its thermoluminescent (TL) response. The oxide Mg1.5InTi0.5O4 present in this system was synthesized by a solid state reaction at 1350 °C in air. The X-ray powder diffraction pattern showed a spinel-type structure for this compound. In this work, this spinel, as well as its TL properties when exposed to beta particles, are being reported for the first time. The glow curve is simple and wide with a TL maximum located at 203 °C at 21.33 Gy. The peak shows a shift to lower temperatures and it increases its intensity, as the irradiation dose increases. The lineal behavior was observed between 10.66 to 341 Gy, and no saturation signs were observed. The relative sensitivity variation was 2.7% and standard deviation after ten consecutive irradiation - TL readout cycles was 1 %. The minimum detectable dose was 5.65 Gy for this spinel-type oxide [3]. These results suggest the possible application of Mg1.5InTi0.5O4 in dosimetry.

Thermoluminescence properties of sintered ZnO

New pellet-shaped ZnO phosphors were synthesized using a controlled chemical reaction. Some samples were sintered at 1123, 1173 or 1223K during 24h in air, and then exposed to beta particle irradiation in the dose range from 25 to 800Gy to investigate their thermoluminescence (TL) properties. By considering their sensitivity, reproducibility, and fading features, samples sintered at 1173K exhibit the best dosimetric characteristics. From computerized glow curve deconvolution that was carried out using a general order equation, the kinetics parameters were computed, and it was found that the glow curves are composed by six individual TL peaks with kinetics order ranging from 1.2 to 1.8.