This study presents a comparison of the X-ray transmission through microsized and nanosized materials. for this purpose CuO nanoparticles, with 13.4 nm average grain size, and CuO microparticles, with a mean particle size of 56 mu m, were incorporated separately to beeswax in a concentration of 5%. Results show that the transmission through the above material plates with microsized and nanosized CuO was almost the same for X-ray beams generated at 60 and 102 kV tube voltages. However, for the radiation beams generated at 26 and 30 kV tube voltages the X-rays are more attenuated by the nanostructured CuO plates by a factor of at least 14%. Results suggest that the difference in the low energy range may be due to the higher number of particles/gram in the plates designed with CuO nanoparticles and due to the grain size effect on the X-ray transmission. (C) 2010 Elsevier B.V. All rights reserved.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)Univ São Paulo, Inst Fis, Dept Fis Nucl, BR-05508090 São Paulo, BrazilCtr Univ Franciscano, Area Ciencias Tecnol, BR-97010032 Santa Maria, RS, BrazilUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09941510 Diadema, SP, BrazilUniv Fed Rio Grande do Sul, Escola Engn, Dept Mat, BR-90035190 Porto Alegre, RS, BrazilUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09941510 Diadema, SP, BrazilFAPESP: 2010/06814-4CNPq: 307095/2008-8Web of Scienc

Basegio, Tania

Bergmann, Carlos Pérez

Botelho, M. Z.

Kunzel, Roseli

Levenhagen, Ronaldo Savarino

Okuno, Emico

Applied Radiation and Isotopes

This study presents a comparison of the X-ray transmission through microsized and nanosized materials. for this purpose CuO nanoparticles, with 13.4 nm average grain size, and CuO microparticles, with a mean particle size of 56 mu m, were incorporated separately to beeswax in a concentration of 5%. Results show that the transmission through the above material plates with microsized and nanosized CuO was almost the same for X-ray beams generated at 60 and 102 kV tube voltages. However, for the radiation beams generated at 26 and 30 kV tube voltages the X-rays are more attenuated by the nanostructured CuO plates by a factor of at least 14%. Results suggest that the difference in the low energy range may be due to the higher number of particles/gram in the plates designed with CuO nanoparticles and due to the grain size effect on the X-ray transmission. (C) 2010 Elsevier B.V. All rights reserved.Univ São Paulo, Inst Fis, Dept Fis Nucl, BR-05508090 São Paulo, BrazilCtr Univ Franciscano, Area Ciencias Tecnol, BR-97010032 Santa Maria, RS, BrazilUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09941510 Diadema, SP, BrazilUniv Fed Rio Grande do Sul, Escola Engn, Dept Mat, BR-90035190 Porto Alegre, RS, BrazilUniversidade Federal de São Paulo, Dept Ciencias Exatas & Terra, BR-09941510 Diadema, SP, BrazilWeb of ScienceFundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAPESP: 2010/06814-4CNPq: 307095/2008-

Kunzel, Roseli [UNIFESP]

Levenhagen, Ronaldo Savarino [UNIFESP]

Repositório Institucional UNIFESP

Applied Radiation and Isotopes 69 (2011) 527–530Contents lists available at ScienceDirectApplied Radiation and Isotopes0969-80doi:10.1 CorrE-mjournal homepage: www.elsevier.com/locate/apradisoX-ray transmission through nanostructured and microstructuredCuO materialsM.Z. Botelho a, R. Ku¨nzel b,, E. Okuno b, R.S. Levenhagen c, T. Basegio d, C.P. Bergmann da A´rea de Cieˆncias Tecnolo´gicas, Centro Universita´rio Franciscano, Rua dos Andradas, 1614, CEP 97010-032 Santa Maria, RS, Brazilb Universidade de S ~ao Paulo, Instituto de Fı´sica, Departamento de Fı´sica Nuclear, Cidade Universita´ria, CEP 05508-090 S ~ao Paulo, SP, Brazilc Universidade Federal de S~ao Paulo, Departamento de Ciencias Exatas e da Terra, Rua Arthur Ridel, 275, Jardim Eldorado, CEP 09941-510 Diadema, SP, Brazild Universidade Federal do Rio Grande do Sul, Escola de Engenharia, Departamento de Materiais, Avenida Osvaldo Aranha, 99, CEP 90035-190 Porto Alegre, RS, Brazila r t i c l e i n f oArticle history:Received 31 May 2010Received in revised form31 October 2010Accepted 4 November 2010Keywords:CuO nanoparticlesCuO microparticlesX-ray attenuation43 & 2010 Elsevier Ltd.016/j.apradiso.2010.11.002esponding author.ail address: roselikunzel@gmail.com (R. Ku¨nzOpen access under the a b s t r a c tThis study presents a comparison of the X-ray transmission throughmicrosized and nanosizedmaterials.For this purpose CuOnanoparticles, with 13.4 nmaverage grain size, and CuOmicroparticles,with ameanparticle size of 56 mm, were incorporated separately to beeswax in a concentration of 5%. Results showthat the transmission through the above material plates with microsized and nanosized CuO was almostthe same for X-ray beams generated at 60 and 102 kV tube voltages. However, for the radiation beamsgenerated at 26 and 30 kV tube voltages the X-rays aremore attenuated by the nanostructured CuOplatesby a factor of at least 14%. Results suggest that the difference in the low energy range may be due to thehigher number of particles/gram in the plates designed with CuO nanoparticles and due to the grain sizeeffect on the X-ray transmission.& 2010 Elsevier Ltd. Open access under the Elsevier OA license.1. IntroductionNanostructured materials are deﬁned as those materials whosestructural elements have dimensions in the 1–100 nm range(Moriarty, 2001). These materials can be composed of nano sizegrains, which consist of many atoms (Lines, 2008). Grains ofconventional materials have sizes that are in the range of tens ofmicrons to one or moremillimetres (Lines, 2008). Due to their verysmall size, thesematerials can present novel chemical and physicalproperties relative to the same chemical compound with dimen-sions in the microscopic or macroscopic range (Poole and Owens,2004). Nanomaterials can also exhibit enhanced mechanical per-formance and offer interesting possibilities for structural applica-tions (Poole and Owens, 2004; Lines, 2008).Recent publications in the literature propose the use of nano-particles and nanostructures embedded in a polymeric matrix forX-ray and gray shielding purposes (Friedman and Singh, 2003;Taylor, 2007; Haber and Froyer, 2008). In fact, some properties ofnanostructured materials are attractive for radiological protectionapplications, especially in the design of lighter and lead-free apronsfor individual protection (Scuderi et al., 2006). However, theapplication of nanostructures for radiological protection purposesstill requires to evaluate if these materials attenuate the X-raybeams in the same form as the conventional materials.el).Elsevier OA license.In this work we have measured the X-ray transmission throughmicrosized and nanosizedmaterials. For this purpose, copper oxide(CuO)microparticles have been used as the startingmaterial in theproduction of the CuO nanoparticles. These microparticles andnanoparticleswere incorporated to beeswax and rectangular plateswere produced for eachmaterial. The X-ray transmissionmeasure-ments through these materials were carried out for X-ray beamsgenerated with the voltage ranging from 26 to 102 kV.2. Materials and methods2.1. Samples productionCuO nanoparticles have been of great interest due to theirpotential applications in many important ﬁelds of science andtechnology such as gas sensors, magnetic phase transitions,catalysts and superconductors (Zhu et al., 2004). Besides, copper(Cu) ﬁlters are used in conventional radiology clinical procedures inorder to improve image quality and reduce the radiation dosedelivered to the patient.In this work, CuO nanoparticles with a mean grain size of13.4 nm and CuO microparticles with 56 mm average particle sizewere used in order to investigate the X-ray transmission throughthese materials. The CuO microparticles (Vetec Quı´mica Fina,Brazil), with 97% purity, were used as starting material in thenanoparticle production. Nanoparticles were produced by theusual combustion method (Toniolo et al., 2010). The grain sizeM.Z. Botelho et al. / Applied Radiation and Isotopes 69 (2011) 527–530528was determined by means of X-ray diffraction using Cu Karadiation on a Phillips X-ray diffractometer (model X’Pert MPD)(Toniolo et al., 2010).Plates composed of CuO and beeswax were produced byincorporating CuO particles to beeswax in a concentration of 5%.One group of plates was produced by incorporating CuO nanopar-ticles to beeswax. The second group of plates was produced bymixingmicrosizedCuOparticles to beeswax. A third group of platesof pure beeswax was also produced. The dimension of each platewas about 10 cm10 cm and thickness 2 mm. A total number ofsix plates of each type were prepared. The chemical analysis of thebeeswax plateswere performedwith the aid of a Perkin-Elmer CNH2400 equipment. The measured chemical content is hydrogen83.1770.03%, carbon 14.0670.01% and nitrogen 0.9070.01%.2.2. X-ray transmission measurementsThe X-ray attenuation measurements were carried out bypositioning each material samples, separately, at 30 cm from thefocal spot and the ionization chamber at 30 cm from the samples(Fig. 1). X-ray attenuation measurements were performed for tubevoltages between 26 and 102 kV. X-ray beams with 60 and 102 kVFig. 1. Illustration of the experimental setup used in the measurements of thetransmitted radiation through thematerials in a clinical mammography system andin a conventional radiology equipment. The collimator corresponds to those internalto the clinical equipment provided by the fabricant.Fig. 2. Illustration of the experimental setup used in the spectra metube voltages were generated by a Philips Duodiagnostic digitalequipment with a tungsten anode tube connected to a three-phasegenerator. X-ray beams with voltages between 26 and 30 kV wereproduced by a GE clinical mammography unit, model SenografeMMR, with a molybdenum (Mo) anode tube and Mo ﬁlter alsoconnected to a three-phase generator. The ionization chamber usedin the exposure measurements in conventional radiology was a105–6 and in mammography a 105–6 M, both coupled to aradiation monitor model 9015, and manufactured by Radcal(Radcal Co, USA).The X-ray beams emitted by both equipments were character-ized through themeasurement of the half value layer (HVL) and thevoltage applied to the X-ray tube. The experimental kV valueswereobtained at both systemswith a non-invasive kVpmeter RTI,modelPMX III (RTI Electronics AB). For each X-ray equipment the HVLvalues were evaluated by using aluminum foils, with thicknessesbetween 0.05 and 1 mm, purity 99%.The X-ray attenuation by the beeswax+CuO samples containingnanoparticles or microparticles and pure beeswax has beenevaluated for a large range of mass per unit area and X-ray beamenergies. In all cases the irradiated area by the X-ray beam, at adistance of 30 cm from the focal spot, has been ﬁxed as 5 cm5cm. For each plate set the measurements were performedthree times.2.3. X-ray spectroscopySpectrum measurements were carried out with the aid of aPhilips equipment MG 450 model, designed for industrial applica-tions, connected to a constant potential generator. The detectorsystem used in the X-ray spectra measurements was a XR-100T-CdTe/PX4 (Amptek, Inc., Bedford, MA) with 3 mm3 mm nominalactive area and nominal depletion layer thickness of 1 mm. Thissystem is cooled by Peltier cells to around 243 K and has a 100 mmBe window. An Amptek tungsten collimator with 1000 mm aper-ture and 2 mm in thickness was used in front of the detector. Theenergy calibration of the spectrometer was performed by using themeasured spectra of grays and X-rays emitted by 241Am, 133Baand 152Eu radioactive sources. Fig. 2 presents a schematic setup ofthe experimental arrangement used in the measurement of thetransmitted radiation through the samples. Transmitted spectrameasurement have been performed in the industrial system withthe detector positioned in the center of the radiationﬁeld at 480 cmfrom the focal spot. A lead collimator with aperture of 1.6 cm hasbeen positioned after the sample (Fig. 2). Alignment between thefocal spot and CdTe detectorwas performed by using a laser device.X-ray spectra were generated at a nominal tube voltage of 26 kVand 126 mAs. Experimental spectra measured with CdTe detectorwere corrected for all possible partial interactions of incidentphotons with the detector (Ku¨nzel et al., 2006).3. Results and discussionFig. 3 presents the results related to the X-ray transmissionthrough pure beeswax, microsized CuO incorporated to beeswaxand nanosized CuO incorporated to beeswax. The data have beenasurements of the transmitted radiation through the materials.Fig. 3. Transmission of X-ray beams through microsized and nanosized CuO incorporated to beeswax and pure beeswax as a function of the mass per unit area.M.Z. Botelho et al. / Applied Radiation and Isotopes 69 (2011) 527–530 529gathered for beams generated with a maximum energy of 102, 60,30 and 26 keV and in the range of mass per unit area between 0.17and 1.05 g/cm2.According to the results illustrated in Fig. 3 it is possible toobserve that the transmission through the microsized CuO andnanosized CuO, both incorporated to beeswax, does not providedifferences for X-ray beams generated for 60 and 102 kV tubevoltages. On the other hand, the transmitted air kerma throughthese samples, measured for X-ray beams generated at 26 and30 kV tube voltages, is more attenuated, by a factor of at least 14%,by the nanosized CuO incorporated to beeswax with respect to themicrosized CuO ones over the entire range of mass per unit areastudied in this work.The difference in the X-ray attenuation by CuO microsized andnanosized materials for low energy beams probably cannot beassigned to theparticles distribution in thebeeswaxonce this effectis not observed in the transmission of high energyX-ray beams. TheX-ray beams generated by the Mo/Mo anode/ﬁlter mammographyequipment, with a maximum energy of 26 and 30 keV, arecomposed mainly by photons with energy lower than 20 keV,speciﬁcally at 17.44 and 19.6 keV, that corresponds to the energy ofthe characteristic X-rays emitted by molybdenum.In the diagnostic energy range, the total attenuation by amaterial is determined by both photoelectric and Compton inter-actions. Basically, in the low energy range, the photons interactwith thematerialsmainly bymeans of photoelectric effect,while atthe high energy range the Compton scattering dominates. Attenua-tiondecreaseswith increasingphotonenergy because of the energydependence of the photoelectric effect. The total X-ray attenuationcross-section for the mixture CuO + beeswax presents a K-edgelocated at 8.98 keV, which is due to the Cu present in the material.At the K-edge the attenuation is increased. As the photons energyincreases the total attenuation by the mixture decreases. Besides,due to the particle size, the number of Cu particles/gram in thenanostructured plates is higher than that for the microsizedmaterial. Therefore the probability of a low energy X-ray photonto interact and to be absorbed may be higher for nanostructuredmixture than for the microstructured material.The inﬂuence of the sample grain size on the intensity oftransmitted radiation has been addressed by several authors inthe literature (Berry, 1970; Holynska, 1972). These studies presentresults relative to grains with size in the range between 30 and300 mm. According to the results presented by Holynska (1972) thegrain size effect decreases signiﬁcantly with increasing absorbedradiation energy. On the other hand, according to this author thegrain size effect increases with the increase of the mass per unitarea of the sample.In Fig. 4 the ratio between the air kerma values transmittedthrough themicrosizedmaterial and through the nanosized ones isdisplayed as a function of the mass per unit area and X-ray beamenergy. In this ﬁgure KM stands for the transmitted air kermathrough the microsized material whereas Kn stands for thenanosized ones. The data show that for the X-ray beam generatedwith a maximum energy of 60 keV, this ratio remains about 1.0over all themass per unit area range, that is, the X-ray transmissionthrough bothmaterials is about the same over all themass per unitarea studied in this work. The results for the 102 kV beams aresimilar to those calculated for the 60 kV beams. On the other hand,for the X-ray beams generated with a maximum energy of 26 and30 keV, the effect of the grain size on the X-ray transmissionincreases with increasing of mass per unit area of the sample. Theresults gathered in this work are in agreement with the resultspublished in the literature for grains with dimensions in the rangebetween 30 and 300 mm.Fig. 5 presents themeasured X-ray spectra transmitted through0.1770.02 g/cm2 of the microsized and nanosized materials. TheFig. 4. Experimental dependence of grain size effect with the radiation energy andmass per unit area for the samples produced with CuO microparticles, 56 mm, andCuO nanoparticles, 13.4 nm, both incorporated to beeswax.0.0E+002.0E+034.0E+036.0E+038.0E+031.0E+041.2E+040 5 10 15 20 25 30CountsEnergy (keV)microsized CuOnanosized CuOFig. 5. Transmitted energy spectra through themicrosized and nanosizedmaterialsmeasured for 26 kV tube voltage.M.Z. Botelho et al. / Applied Radiation and Isotopes 69 (2011) 527–530530spectra have been measured by using a nominal tube voltage of26 kV and the data were registered with the aid of a CdTe detector.The data displayed in Fig. 4 show that in the low energy range, thenanostructured material is more effective to absorb the radiation,mainly the photons with energy lower than 20 keV where thephotoelectric effect dominates.4. ConclusionThis work compares the X-ray beams attenuation by nanostruc-tured and microstructured materials. For this purpose air kermavalues related to X-ray beams emitted with maximum energy of 26,30, 60 and 102 keV have been measured. Results show that thetransmitted air kerma values, for X-ray beams produced at 60 and102 kV, are about the same for the samples with nanosized CuO andsamples with microsized CuO. On the other hand, for beamsgenerated at 26 and 30 kV, the air kerma values are lower for thesamples produced with nanosized CuO. Therefore, the samples withnanostructured CuO are more effective for low energy X-ray photonsattenuation compared to the samples producedwithmicrostructuredCuO. These results suggest that the nanostructured materials can beeffectively used for radiological protection purposes because theX-ray attenuation by thesematerials is about the same or higher thanthose observed for microstructuredmaterials. However, the compar-ison of the X-ray absorption by other nanostructured materials isnecessary in order to evaluate if they also present a similar attenua-tion pattern as CuO nanoparticles.AcknowledgmentsThe authors thank Clinica Radiolo´gica Caridade, Santa Maria/RSfor providing their X-ray equipments for this research. This workwas partially supported by Brazilian Agency Fapesp (Fundac- ~ao deAmparo a Pesquisa do Estado de S~ao Paulo) through Process 2010/06814-4 and CNPq through grant 307095/2008-8.ReferencesBerry, P.F., 1970. Particle size heterogeneity phenomena in X-ray analysis. In: ThirdSymposium of Low Energy X- and Gamma Ray Sources and Applications, BostonCollege Massachusetts.Friedman, H.W., Singh, M.S., 2003. Radiation Transmission Measurements forDemron Fabric, Lawrence Livermore National Laboratory, Livermore, CA.Haber, F.E., Froyer, G., 2008. Transparent polymers embedding nanoparticles forX-rays attenuation. Journal of the University of Chemical Technology andMetallurgy 43 (3), 283–290.Holynska, B., 1972. Study of the effect of grain size heterogeneity in the X-rayabsorption analysis of simulated aqueous slurries. Spectrochimica Acta 27B,237–245.Ku¨nzel, R., Herdade, S.B., Costa, P.R., Terini, R.A., Levenhagen, R.S., 2006. Ambientdose equivalent and effective dose from scattered X-ray spectra in mammo-graphy for Mo/Mo, Mo/Rh and W/Rh anode/ﬁlter combinations. Physics inMedicine and Biology 51, 2077–2091.Lines, M.G., 2008. Nanomaterials for practical functional uses. Journal of Alloys andCompounds 449, 242–245.Moriarty, P., 2001. Nanostructured materials. Reports on Progress in Physics 64,297–381.Poole Jr., C.P., Owens, F.J., 2004. Introduction to Nanotechnology. Wiley-Interscience.Scuderi, G.J., Brusovanik, G.V., Campbell, D.R., Henry, R.P., Kwone, B., Vaccaro, A.R.,2006. Evaluation of non-lead-based protective radiological material in spinalsurgery. The Spine Journal 6, 577–582.Taylor, E.W., 2007. Organics, polymers and nanotechnology for radiation hardeningand shielding applications. SPIE 6713 (671307), 1–10.Toniolo, J.C., Takimi, A.S., Bergmann, C.P., 2010. Nanostructured cobalt oxides (Co3O4and CoO) and metallic Co powders synthesized by the solution combustionmethod. Materials Research Bulletin 45, 672–676.Zhu, J., Li, D., Chen, H., Yang, X., Lu, L., Wang, X., 2004. Highly dispersed CuOnanoparticles prepared by anovel quick-precipitationmethod.Materials Letters58 (26), 3324–3327.

X-ray transmission through nanostructured and microstructured CuO materials

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