Gamma Dose Range Research Articles

Gamma irradiated Er3+ ions doped Li2O–BaO–B2O3–P2O5 glasses: Structural, optical, and thermoluminescence glow curve analysis

Lithium barium borophosphate glasses doped with Er3+ rare earth ions are reported in terms of their physical, optical, structural, and thermoluminescence (TL) properties in this study. The melt quenching method was used to synthesize the glasses with varying concentration of the dopant (0.0, 0.2, 0.4 0.6, 0.8 and 1.0 mol%). A thorough analysis of physical characteristics, including their variation with erbium oxide, has been conducted. The amorphous phase of the as-quenched samples has been validated through X-ray diffraction patterns, while Fourier transform infrared spectroscopy confirmed the existence of different structural groups. UV–Vis–NIR spectroscopy at wavelengths ranging from 200 to 1100 nm has been utilized to investigate various optical properties. In the gamma dose range of 50 Gy to 10 kGy, the glass sample with 0.6 mol% of erbium concentration (LBPEr0.6) showed the maximum integrated TL intensity with an optimized heating rate of 5 °C/s and annealing temperature of 400 °C. The deconvolution of TL glow curves was done using the R-package “tgcd: Thermoluminescence Glow Curve Deconvolution" by employing the Kitis general order kinetics model. Chen's peak shape approach has been used to calculate the trapping parameters, including order of kinetics (b), shape factor (μg), frequency factor (s), and activation energy (E). The ideal thermoluminescence dosimeter characteristics showed that LBPEr0.6 glass has outstanding linearity, excellent sensitivity, minimal fading and good reproducibility over six cycles.

Dosimetric properties of Cr–La, Cr–Cu, and Cu–La ions codoped Ca9 Al (PO4)7 nanostructure

In the present work, Cr–La, Cr–Cu, and Cu–La ions codoped Ca9Al (PO4)7 nanostructures (symbolized as Cr–La, Cr–Cu, and Cu–La) were prepared using the sol-gel method for their dosimetric properties. X-ray diffraction (XRD) and transmission electron microscopy (TEM) results reflected the existence of the nanoparticle structure. This confirmed the successful sol-gel preparation method used. The surface morphological properties of the prepared samples were scrutinized by scanning electron microscopy (SEM). The presence and distribution of the constituent elements of the samples were determined using energy-dispersive X-ray (EDX) spectroscopy. The thermoluminescence (TL) sensitivity enhancement and homogenous properties of the prepared samples were assessed using a γ-radiation dose of 5 Gy. TL sensitivity of the Cr–Cu sample was found to be optimum. The relative standard deviations (RSD) of the homogenous study were found to be 6.5, 5.7, and 3.9% for Cr–La, Cr–Cu, and Cu–La, respectively, which were acceptable according to the ISO requirements (<10%). The dose-linearity response was investigated in 0.5 up to 20 Gy γ-dose ranges. The sample Cr–Cu had a good dose-linearity of up to 20 Gy while the others (Cr–La and Cu–La samples) had a dose-linearity of up to 13 Gy. The threshold doses (MDD) of the Cr–La, Cr–Cu, and Cu–La samples were computed and found to be approximately 110, 32, and 134 μGy, respectively. The photon attenuation parameters of the prepared samples were computed using the Phy-X PSD program, and the acquired data showed that the Ca9Al (PO4)7 composition had bone-equivalent material characteristics. Results of the dosimetric properties of Cr–La, Cr–Cu, and Cu–La co-doped Ca9Al (PO4)7 samples suggested that these compositions had potentially excellent TL characteristics to be used in various dosimetric applications across a broad range of gamma doses.

Synthesis and evaluation of Li2O-2B2O3 glass chips for gamma radiation dosimetry applications

We report the fabrication of 10 mm × 10 mm × 1 mm, Li2O-2B2O3 glass chips using melt quench method. Melt produced due to solid state reaction between Li2CO3 and H3BO3 at 950°C, quenched at stainless steel die and annealed at 350°C resulted in production of highly transparent glass chips. Glass chips irradiated to various gamma radiations and thermo-luminescence measurement performed using linear temperature profile with heating rate 2°C/s. A broad glow curve is obtained with peak at 185°C. Further linearity of TL response with gamma dose studied in gamma dose range 100 mGy to 50 Gy. TL intensity and integrated counts are found linearly with gamma dose. The TL sensitivity of glass chips were found to be ∼52 counts/mGy. Repeatability of TL Dosimetric performance is found to be within ±10% and dose rate dependence is also found within ±10% in 50 mGy/hr to 3000 mGy/hr dose rate range. The prepared glass chips can be utilized as thermo-luminescent dosimeter for gamma dose 100 mGy and higher.

Thermoluminescence studies of zinc borate (ZnB2 O4 ) phosphor doped with rare earths for dosimetric aspects.

A series of ZnB2 O4 phosphors doped with different concentrations of Eu and Dy (0.05 0.1, 0.2, 0.5, 1.0mol%) and co-doped with Ce (1, 2, 5, 7, 10mol%) respectively was prepared via the solid-state reaction technique and the thermoluminescence (TL) behaviour of gamma ray-irradiated samples was studied. The synthesized samples were irradiated with γ-rays for the dose range 0.03-1.20 kGy. The TL intensity variations with dose, dopant concentration, and the effect of co-doping were studied. The TL response curves for ZnB2 O4 :Eu3+ and ZnB2 O4 :Dy3+ , ZnB2 O4 :Eu3 ,Ce3+ and ZnB2 O4 :Dy3+ ,Ce3+ phosphor were observed. It was revealed that ZnB2 O4 :Eu3+ showed a linear TL behaviour for the dose 0.03-1.20 kGy and ZnB2 O4 :Dy3+ showed linearity for the gamma dose range 0.03-0.10kGy. Furthermore, fading for all the samples was observed to be less than 10% for a storage period of 30 days. In addition to this, the trapping parameters, especially activation energies were evaluated using the Ilich method and the initial rise method. The activation energy values obtained from both methods were in complete agreement with each other.

Thermoluminescence Properties of Bioglass for Radiation Dosimetry

The thermoluminescence technique was employed to study bioglass matrix prepared using the traditional technique of glass making. The synthesized bioglass matrix were investigated using X-ray diffraction (XRD), and differential thermal analysis (DTA) has been studied. The highest thermoluminescent intensity was found for composition bioglass 26.91 % CaO, 45.68 % SiO2, 2.50 % P2O5, 25.094 %Na2O (mol%), with only one glow peak at 460 k. The TL response illustration is slightly sub-linear in the high gamma dose range from 25 to 1000 Gy. This new glass system might become useful in high-dose fields for dosimetry.

Dosimetry Characterization of Unknown Dye Polyvinyl Alcohol Films

In the present study chemical dosimeters having aqueous solutions of crystal violet commercial dye were irradiated by Co60 γ source in the range (0-120)KGy. The standard aqueous solutions were scanned by UV/VIS spectrophotometer for the determination of maximum wave length (λmax) which was found to be 591nm at this value maximum absorbance was found to be 3.5; it was also observed that with increase in dose, absorbance decreases correspondingly. At this value, the absorbance (A) of irradiated samples was measured in UV region. The plot between concentration C and A gave approximate linear relationship and hence verified Beer’s Law which proved that these dye solutions can satisfactorily be used as the dye dosimeters in 0-120kGy gamma dose range.

Gamma dosimetric properties of radiophotoluminescent CaSO4:Eu3+ with novel readout instrument

We report investigations carried out on radiophotoluminescence (RPL) response of Eu3+ doped CaSO4 phosphor using an in-house developed compact system for gamma dosimetry. The system comprises a sample holder to hold 200 mg phosphor powder having particle sizes 90–212 µm in the disc form (15 mm dia, 1 mm thick) and a microcontroller-based reader with Hamamatsu PMT (H10720-110) for collection of emitted luminescence. Conversion of Eu3+ to Eu2+ on gamma irradiation in phosphor samples is studied with 320 nm UVLED (FWHM 10 nm) stimulation. The performance of the system is evaluated in 100 mGy to 10,000 mGy gamma dose range and a linear response is observed. The dosimetric properties of synthesized phosphor in terms of gamma dose response, reproducibility, dose rate response, relative photon energy dependence and fading are reported.

Thermoluminescence characteristics of lithium borosilicate glass doped with Sm2 O3.

Lithium borosilicate glass composite (SiO2 -Li2 CO3 -H3 BO3 ) doped with various concentrations of Sm2 O3 (0-0.7 mole %) was prepared using the melt quenching method. The investigated thermoluminescence (TL) characteristics of the prepared system revealed that the highest TL response was obtained for this glass composite at 0.05 mol% Sm2 O3 . In this study, the 0.05 mol% Sm2 O3 -doped lithium borosilicate glass composite was subjected to detailed dosimetric investigation in terms of its annealing condition, dose-response, and minimum detectable dose. The reproducibility of the response, thermal characteristics, and optical fading were also studied. The obtained results showed that the prepared glass composite had a linear dose-response over the wide gamma dose range 2Gy to 2 kGy, as well as reasonable thermal fading and excellent reproducibility. These attributes render the composite under investigation promising for utilization in radiation detection.

Particle size dependent TL response of CaF2:Dy phosphor for gamma dosimetry

CaF2:Dy phosphor was prepared by ball milling method over particle size ranging from 140 nm to 35 nm, and their thermoluminescence properties were studied by irradiation with 60Co gamma rays. The XRD revealed that the crystallite size was of ∼45 nm for pristine, 19.1 nm for 10 h and 9.99 nm for 50 h ball-milled phosphor samples and confirmed by FESEM. The UV–visible spectra indicate that the absorption and scattering of radiation increased with a decrease in the particle size along with the blue shift in the absorption peak. CaF2:Dy particles of different sizes were irradiated with gamma dose from 1 Gy to 20 kGy and respective thermoluminescence response was studied. It was observed that the ∼65 nm particle size phosphor showed a linear response with gamma dose range from 1 Gy to 12 kGy. These results reveal that the CaF2:Dy phosphor can be used for high gamma radiation measurement and food irradiation dosimetry.

Gamma irradiation dose dependent nano-structural, optical and impedance spectroscopy of PdS thin films

Gamma irradiation is recognized to modify the properties of thin films. In the present work, the effects of gamma irradiation on the nano-structural electrical and optical properties as of function of radiation dose has been studied. The PdS thin films deposited on glass substrate by successive ion layer adsorption and reaction (SILAR). The deposited thin films were irradiated by the gamma radiation with the 60Co for the Gamma dose range from 0 to 100 kGy. As deposited and gamma irradiated PdS thin films were investigated by impedance spectroscopy, X-ray diffraction, energy dispersive X-ray, scanning electron microscopy and Photoluminescence. The X-ray diffraction patterns exhibited a tetragonal structure of PdS thin films before after gamma irradiation, and demonstrated the changes in crystallinity, dislocation density, crystallite size and micro-strain. Field emission scanning electron microscopy and energy dispersive X-ray study conformed atomic composition of PdS thin film (1:1 ratio of Pd:S) and revealed that shape and size of grain depend on dose of gamma irradiation. Photoluminescence peak are found to be shifted to longer wavelength, intensity and width of photoluminescence peak increased for the gamma irradiated samples with increasing gamma dose. Impedance spectroscopy revealed that the enhancement of charge carrier density of irradiated PdS thin films increased linearly with gamma dose. The achieved results prove that gamma irradiation has superficial influence on nano-structural, optical and electrical properties of the deposited PdS thin films.

Influence of mono energetic gamma radiation on structural and electrical properties of TiO2 thin film coated on p-type porous silicon

Titanium dioxide thin film was coated on p-type porous silicon by sol–gel spin coating method. The prepared samples were irradiated by the mono-energetic gamma radiation at Auto-irradiation facility with the Cesium-137 for the Gamma dose range from 100 to 1000 mSv. Gamma irradiated samples revealed that the physical changes of titanium oxide/porous silicon layer found to be varying with increasing gamma dose. The irradiated titanium oxide/porous silicon layer were investigated by scanning electron microscopy, X-ray diffraction, Fourier transform infra-red, Photoluminescence and I–V characteristics studies. The surface morphology of the irradiated titanium oxide/porous silicon layer has shown deformation with increasing gamma dose. The X-ray diffraction patterns of titanium oxide/porous silicon layer after irradiation revealed changes in crystallite size, dislocation density, strain and phase content. These changes in anatase (004) are linear with gamma dose than the rutile (310) of TiO2-PSi. Fourier transform infra-red spectrums of the irradiated samples showed an increase in intensity of vibration modes with the increase of the radiation dose. Photoluminescence peaks are found to be in the range of 330 to 360 nm for all the irradiated samples and the intensity of Photoluminescence peak increased for the irradiated samples with increasing gamma dose. I–V Characteristics revealed that the electrical conductivity of irradiated samples increased linearly with gamma dose. The linear changes in electrical property of titanium oxide/porous silicon under the influence of mono-energetic gamma photons gives a positive indication that it can be further studied for the development of radiation sensor for applications in nuclear field.

Thermoluminescence and Kinetic Analysis of Gamma Irradiated Some Rocks from Makkah, Saudi Arabia

In the present work some rocks were collected from Makkah, Saudi Arabia. Thermoluminescence technique utilized to investigate the ability of the sample to use as an accidental radiation dosimetry. After γ-ray irradiation by Co-60 source, Makkah rocks sample revealed a peak at 155°C. The peak position is decreased with the increase of the γ-dose. Chemical analysis of Makkah rocks were achieved by using XRF technique. The natural fading, the effect of temperature on the ability of the sample to store the TL-signal and the optimum grain size of the sample were studied. The activation energy was calculated by using peak shape method. The TL-signal exhibits a linear response through the gamma dose range 10Gy-10KGy. In this range of exposure the sample under study can be considered as an accidental dosimetry. The natural fading, the effect of temperature on the ability of the sample to store the TL-signal and the optimum grain size of the sample were studied. The activation energy was calculated by using peak shape method.

The crosslinking behaviour of cellulose in gamma irradiated paper

The behaviour of cellulose-based materials in a relatively low gamma dose range (less than 10 kGy) is of interest for the application of ionizing radiation for the preservation of cultural heritage. Different relationships between the absorbed dose and number of scissions or degree of polymerization (DP) were established on a large dose range (over 100 kGy). The significant decrease of DP was confirmed for doses range of interest for cultural heritage preservation, for pure cellulose paper and other sorts of commercial paper. However, other physical properties of the paper have less or no change for irradiation at doses below 10 kGy.The purpose of this study is to evaluate the changes induced by gamma irradiation to the hydrogen bonds structure in cellulose, in a low dose interval, by thermal analysis and infrared spectroscopy.Our results confirm the crosslinking behaviour for Whatman paper at low irradiation doses. A similar behaviour was observed for copy paper but with reduced intensity and higher statistical errors. This behaviour can explain why mechanical resistance of irradiated paper remains unchanged below a certain dose, as previously reported in a number of studies. The carbonyl content shows a continuous increase over the tested dose range but the increase of carbonyl content in Whatman paper at doses lower than 10 kGy is lower than the initial carbonyl content of copy paper. The ionizing radiation treatment for cultural heritage is not nonintrusive in case of paper but the degradation risks are minimal for doses below 10 kGy.

Investigating thermoluminescent properties of nanocrystalline lithium borate doped with dysprosium

We investigate the thermoluminescence (TL) properties of nanocrystalline Li2B4O7:Dy. The TL properties of the said phosphor are of great interest as it has an effective atomic number close to that of a biological tissue. The phosphor is synthesized by combustion method and characterized by X-ray diffraction and transmission electron microscopy. When the nanophosphor is exposed to a range of gamma doses using cobalt-60, it exhibits a linear TL response for an extensive range of doses. Further, the reproducibility and batch homogeneity properties are also studied. In conclusion, nanocrystalline Li2B4O7:Dy shows potential as a radiation dosimeter of gamma rays.

Enhanced radiation tolerance in Mn-doped ferroelectric thin films

This work investigates the role of Mn-doping of ferroelectric lead zirconate titanate (PZT) thin films exposed to a range of ionizing radiation doses. PZT thin films were fabricated with both undoped and 4% Mn-doped compositions, and the functional response was compared both before and after exposure to gamma radiation doses up to 10 Mrad. A phenomenological model was applied to quantify defect interactions and compare trends in the degradation of the functional response. Mn-doped PZT samples demonstrate reduced magnitude of functional response in non-irradiated samples but exhibit vastly superior radiation tolerance of dielectric and ferroelectric properties across the range of gamma doses studied here. Strong MnZr/Ti″−VO·· defect dipoles pin domain walls, resulting in a lower initial functional response and mitigating the deleterious effects of irradiation on extrinsic contributions to the said response. Piezoelectric response trends as a function of radiation dose are highly nonlinear. The results of this work can be leveraged to engineer next-generation radiation-tolerant ferroelectric materials for applications where high levels of functional response stability are required, especially at elevated ionizing radiation dose.

Dosimetric and kinetic characteristics of watch glass sample

This paper reports the Electron Spin Resonance (ESR) and Thermoluminescence (TL) dosimetric and kinetic characteristics of commercial watch glass. Both of the ESR and TL response of the watch glass sample yielded linear behavior in the 0.5–135 Gy gamma dose range. ESR dosimetric properties of watch glass sample like dose-rate dependence, signal reproducibility and fading behavior have also been studied in detail. Kinetic behavior and activation energy of the radiation induced free radicals responsible from the ESR spectra of watch glass sample were determined. The TL kinetic parameters such as activation energy (E), frequency factor (s), order of kinetics (b) were also calculated by applying the methods of initial rise (IR), isothermal decay (ID), variable heating rate (VHR) and de-convolution.

Thermoluminescence and glow curves analysis of γ-exposed Eu3+ doped K3Y(PO4)2 nanophosphors

Eu3+ doped K3Y(PO4)2 nanophosphor was synthesized by combustion synthesis using urea as a fuel. The crystal structure and particle morphology of the nanophosphor were investigated by using X-ray diffraction and transmission electron microscopy, respectively. A Thermoluminescence (TL) study was carried out after exposing the samples to gamma radiation. The TL glow curves exhibited a prominent peak at 407K and a small hump at 478K. The intensity of the peaks increased with the increase in the dose of the gamma rays (0.01–5kGy). The K3Y(PO4)2: Eu3+ (2.5mol%) nanophosphor exhibited sublinear TL response to γ-radiation over a wide range of gamma doses (0.01–5kGy). The TLanal program was used to analyze the glow curves of the K3Y(PO4)2 nanophosphor at different doses (0.2–5kGy) and different heating rates (3–10K/s). A comparative study was done for kinetic trapping parameters that were determined by the peak shape methods of Chen, Grossweiner and Lushchik. The frequency factors (s) for each glow peak were also calculated. The values of the activation energy (E) obtained by the TLanal program were in good agreement with those obtained by the peak shape methods. The effect of different amount of doses and different heating rates are discussed.

Investigation of thermoluminescence characteristics of gamma irradiated phlogopite mica

The present paper investigates the thermoluminescence (TL) characteristics of phlogopite mica irradiated with gamma rays in the dose ranges from 5kGy to 40kGy. It has been found that at all gamma doses, TL glow curve of phlogopite mica shows a simple glow curve structure with one broad peak around 400K temperature. There is no shift in peak temperature with increase in gamma dose which clearly indicates that TL glow peaks are of first order kinetics. The TL intensity increases linearly up to 30kGy and then shows saturation up to 40kGy which have been explained using TIM and UNIM model. The effect of different heating rates on the TL intensity, TL glow peak temperature and total glow curve area for 10kGy irradiated phlogopite mica has also been studied. Theoretical analysis of TL glow curves of gamma irradiated phlogopite mica has been done by glow curve deconvolution procedure using computerized Glow Fit software and the trapping parameters of isolated TL glow peaks have also been determined. The simple glow curve structure and the linear TL response to a wide range of gamma doses of phlogopite mica confirm its suitability as an effective thermoluminescent material and explore its potential for tremendous applications in radiation dosimetry.

Thermoluminescence features of MgB4O7:Tb phosphor

In the present work, polycrystalline samples of MgB4O7 doped with terbium at different concentrations were synthesized using the solvent evaporation method. The sample doped with 1mol% of Tb presented the highest luminescence intensity. The glow curve of the samples showed an intense and well defined TL peak having the maximum on 220°C and a small shoulder peak at ∼330°C. TL spectra and fluorescence of 1mol% doped sample presented a strong Tb3+ emission lines at 489, 545, 588 and 622nm. The TL dose response was measured over the gamma dose range between 1 and 10Gy. The relationship between peak intensity and dose was linear and the minimum detectable dose obtained by interpolation taking into account three times the standard deviation of the zero dose reading was 50μGy.

Thermoluminescence property of LiMgF3 erbium activated phosphor

The perovskite-like LiMgF3:ErF3 pellets were obtained from the melt formed by LiF and MgF2 mixed salts in the stoichiometric ratio. The perovskite material was doped with 1, 2 and 4mol% of ErF3 impurity. The pellets samples were 60Co gamma irradiated and their thermoluminescence (TL) properties were analyzed, i.e., dose–response, fading at RT and under UV irradiation, TL signal reproducibility, and kinetic parameters. The intensity of the TL response against irradiation dose was increased remarkably by the high concentration of impurity, and a linear dose–response was observed in the range of 1–10Gy. The fading observed at RT was about 10–30% after 24h from irradiation. All samples were exposed from 1 to 200Gy gamma dose range. The TL glow peaks were found around 367–376, 438–447, 509–521, and 594–611K, when the doped samples were 1, 2 and 4mol% of the erbium impurity concentration. The thermoluminescence kinetics parameters of the glow curves have been analyzed using the Computerized Glow Curve Deconvolution (CGCD) method.