Incorporation of photoluminescent 7-hydroxycoumarin units onto a polyethylene matrix by means of gamma radiation
Publication date: Available online 21 May 2019Source: Radiation Physics and ChemistryAuthor(s): Sandra M. Rojas-Montoya, Mireille Vonlanthen, José Manuel Huerta-Roldán, Edgar Aguilar-Ortiz, Guillermina Burillo, Eric G. Morales-Espinoza, Ernesto RiveraAbstractA 60Co source generating gamma radiations was used to graft polyethylene (PE) films with acryloyl chloride (AC). Different doses of radiations (2, 4, 6 and 8 kGy) were employed in order to obtain polymers with different amount of grafted ramifications. Furthermore, the desired photoluminescent polymers (PE-g-AC-CumTEG) were obtained after esterification...
Source: Radiation Physics and Chemistry - May 22, 2019 Category: Physics Source Type: research

Surface chemistry of BSCF material after Ar+ ion treatment and at elevated temperatures
Publication date: Available online 19 May 2019Source: Radiation Physics and ChemistryAuthor(s): Jerzy Kubacki, Abhijit Chanda, Marek Kulpa, Bronisław PsiukAbstractThe microstructure and electronic structure of barium strontium iron cobalt oxide of nominal composition Ba0.5Sr0.5Co0.8Fe0.2O3-δ (BSCF) was studied using Scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS). Chemical states of the iron, cobalt, barium and strontium core levels were identified both from the surface and bulk material. The influence of low energy Ar+ ion bombardment on the electronic structure of the sample was ...
Source: Radiation Physics and Chemistry - May 21, 2019 Category: Physics Source Type: research

The physics of irradiation of biological matter by ion beams
Publication date: Available online 19 May 2019Source: Radiation Physics and ChemistryAuthor(s): M.A. Quinto, J.M. Monti, C.A. Tachino, P.F. Weck, O.A. Fojón, C. Champion, R.D. RivarolaAbstractIn radiobiology, predicting the evolution of irradiated biological matter is nowadays an active field of research to identify DNA lesions or to adapt the radiotherapeutic protocols in radiation oncology. In this context, the numerical methods, based on Monte Carlo track-structure simulations, represent the most suitable and powerful tools for understanding the radiobiological damages induced by ionizing particles. In the presen...
Source: Radiation Physics and Chemistry - May 21, 2019 Category: Physics Source Type: research

Characterization of Te nanoparticles synthesized by plasma processing
Publication date: Available online 17 May 2019Source: Radiation Physics and ChemistryAuthor(s): Fabio Iesari, Keisuke Hatada, Jigar Patel, Chidambara Balasubramanian, Takafumi Miyanaga, Hiroyuki IkemotoAbstractThe local structure of Tellurium nanoparticles synthesized by arc plasma were studied by X-ray absorption spectroscopy. Nanoparticles were characterized by using different techniques to reveal particles size, morphology and composition. Te K-edge EXAFS spectra reveal a structure similar to trigonal Te, where both the inter-chain and intra-chain bonds, typical of Te crystal structure, are present. Evolution of the Deb...
Source: Radiation Physics and Chemistry - May 18, 2019 Category: Physics Source Type: research

The peculiar redox mechanism of copper nitroprusside disclosed by a multi-technique approach
We report the structural analysis on copper nitroprusside (CuNP) used as cathode material in a Li-ion battery during the first lithiation process. The investigation involved a multi-technique approach, where multiple edge Extended X-ray Absorption Fine Structure (EXAFS) refinement has been coupled with Density Functional Theory (DFT) calculations. The reduction occurring at the Cu site involves structural distortion, which is believed to be the main reason for the capacity fading in the first cycles. (Source: Radiation Physics and Chemistry)
Source: Radiation Physics and Chemistry - May 17, 2019 Category: Physics Source Type: research

GEANT4 simulation of exit energy in proton medical imaging
Publication date: Available online 16 May 2019Source: Radiation Physics and ChemistryAuthor(s): R.C.L. Silva, V. Denyak, H.R. Schelin, G. Hoff, S.A. Paschuk, J.A.P. SettiAbstractImaging techniques using protons as incident particles are currently being actively developed as a substitute for X-ray computed tomography and nuclear magnetic resonance methods in proton therapy. In proton imaging, density resolution depends on the position of the maximum of the exit energy distribution and the width of this distribution which influences uncertainty in the definition of the exit energy. In recent years, many research groups have ...
Source: Radiation Physics and Chemistry - May 17, 2019 Category: Physics Source Type: research

Baseline, mapping and dose estimation of natural radioactivity in soils of the Brazilian state of Alagoas
This study aimed at knowing the occurrence of radionuclides 40K, 226Ra and 228Ra in soils in the State of Alagoas, located in the Northeast region of Brazil. A total of 41 samples were collected in the first 25 cm of soil, in order to represent the entire state territory. Samples of the aforementioned radionuclides were processed and analyzed by gamma spectrometry. Activity concentration ranged from (6 ± 1) Bq kg−1 to (2,160 ± 81) Bq kg−1 for 40K (average of 630 ± 25 Bq kg−1), from (5.0 ± 0.4) Bq kg−1 to (63 ± 2) Bq kg−1 for 226Ra (avera...
Source: Radiation Physics and Chemistry - May 17, 2019 Category: Physics Source Type: research

Wavelet analysis of a Cu-oxo zeolite EXAFS simulated spectrum
Publication date: Available online 15 May 2019Source: Radiation Physics and ChemistryAuthor(s): Andrea Martini, Ilia A. Pankin, Anna Marsicano, Kirill A. Lomachenko, Elisa BorfecchiaAbstractIn this work, we focus on the simulated EXAFS spectrum of a Cu-oxo dimer sited in the eight-membered ring of the chabazite zeolite framework. We show the high level of complexity related to the analysis of the second and third shell of the EXAFS-Fourier transform due to the overlap of contributions stemming from atomic species present in the Cu-local environment. Subsequently, we demonstrate the potential of Wavelet Transform Analysis a...
Source: Radiation Physics and Chemistry - May 16, 2019 Category: Physics Source Type: research

XAS study of Mo-based dispersed catalysts for upgrading of heavy oil
Publication date: Available online 15 May 2019Source: Radiation Physics and ChemistryAuthor(s): A.A. Saraev, O.O. Zaikina, G.A. Sosnin, P.M. Yeletsky, A.M. Tsapina, Y.V. Zubavichus, V.A. Yakovlev, V.V. KaichevAbstractResults of X-ray absorption spectroscopy study of Mo-based dispersed catalysts in the coke residue after catalytic steam cracking, catalytic cracking in the absence of water, and hydrocracking processes are reported. It was found that the catalyst precursor (ammonium heptamolybdate) is transformed to three different forms with the different ratios: MoO3, MoO2, and MoS2. After the catalytic steam cracking, the ...
Source: Radiation Physics and Chemistry - May 16, 2019 Category: Physics Source Type: research

Aspects of linear energy transfer (LET) and relative biological effectiveness (RBE) in radiation therapy with positively charged particles and the role of electron capture
Publication date: Available online 14 May 2019Source: Radiation Physics and ChemistryAuthor(s): W. UlmerAbstractIn radiotherapy, dose-effect relations induced by Co60 serve as a reference of the LET and RBE in normal and tumor tissue, which are usually handled by the linear-quadratic model S (LQ) with the parameters α and β, i.e. S = exp (-α·D-β·D2), working excellently up to the shoulder domain. In particle therapy, we have strictly to differ between RBE in the initial plateau and environment of the Bragg peak. Thus for protons LET and RBE of the initial plateau agree with Co60, whe...
Source: Radiation Physics and Chemistry - May 15, 2019 Category: Physics Source Type: research

Photon energy response of LiF:Mg,Ti (MTS) and LiF:Mg,Cu,P (MCP) thermoluminescent detectors: Experimental measurements and microdosimetric modeling
Publication date: Available online 14 May 2019Source: Radiation Physics and ChemistryAuthor(s): Alessio Parisi, Jérémie Dabin, Werner Schoonjans, Olivier Van Hoey, Patrice Mégret, Filip VanhavereAbstractThe photon energy response of six thermoluminescent detector types (6LiF:Mg,Ti, 7LiF:Mg,Ti, natLiF:Mg,Ti, 6LiF:Mg,Cu,P, 7LiF:Mg,Cu,P and natLiF:Mg,Cu,P) was studied in the energy range 12–1250 keV by means of irradiations with different γ-ray sources and X-rays. As expected, for both LiF:Mg,Ti and LiF:Mg,Cu,P detectors, no significant differences were found between the results of detectors...
Source: Radiation Physics and Chemistry - May 15, 2019 Category: Physics Source Type: research

Effects of the π-electrons in fused polycyclic aromatic hydrocarbons on positron annihilation
Publication date: Available online 14 May 2019Source: Radiation Physics and ChemistryAuthor(s): Yijun Du, Junhu Zhao, Chen Wang, Chenze Qi, Yan Li, Hongyu Tao, Peng Zhang, Xingzhong Cao, Baoyi WangAbstractThe mesoporous phenol-formaldehyde resins (PFR) were synthesized using formaldehyde, phenol, F127 template as raw materials by high temperature hydrothermal method under different temperatures. Nitrogen doped mesoporous PFR were synthesized in the same way with another additional raw material HMTA. Two series of carbon materials PCs and PCNs were obtained after calcinating PFR at 700, 800, 900 °C. N2 adsorption anal...
Source: Radiation Physics and Chemistry - May 15, 2019 Category: Physics Source Type: research

Assessment of 131I and 99mTc activity concentration under environmental optics
This study presents the activity concentrations – AC – of 131I and 99mTc in sewage samples collected at a medical facility in the city of Rio de Janeiro. Analysis and measurements by gamma spectrometry were carried out using two detectors: a NaI(Tl) scintillator and an HPGe semiconductor. The levels of AC of 131I present in all samples collected and those of 99mTc present in most samples were above their respective values recommended by the current norm. The detected activities in liquid wastes show the need to regulate their release, so that the acceptable limits of risk related to the environmental radiologic...
Source: Radiation Physics and Chemistry - May 15, 2019 Category: Physics Source Type: research

Cultural heritage science at CNA (seville, Spain): Applications of XRF and IBA techniques to art and archaeological objects.
Publication date: Available online 12 May 2019Source: Radiation Physics and ChemistryAuthor(s): F.J. Ager, M.A. Respaldiza, S. Scrivano, I. Ortega-Feliu, A. Kriznar, B. Gómez-TubíoAbstractThe use of nuclear analytical techniques has experienced an extraordinary growth in recent decades in the field of cultural heritage. Nowadays, their use in the study of objects of interest in heritage has become essential. An important effort has been made since the 90s by the archaeometry research group of the Centro Nacional de Aceleradores, CNA (Sevilla, Spain) to develop different non-destructive analytical techniques f...
Source: Radiation Physics and Chemistry - May 13, 2019 Category: Physics Source Type: research

Realization of dysprosium doped lithium magnesium borate glass based TLD subjected to 1–100 Gy photon beam irradiations
Publication date: Available online 12 May 2019Source: Radiation Physics and ChemistryAuthor(s): S. Hashim, R.S. Omar, S.K. GhoshalAbstractWe explored the feasibility of using Dy2O3 doped lithium magnesium borate (LMB) glass based thermoluminescence dosimeter (TLD) for high dose dosimetry in the range 1–100 Gy. Such glass system having composition (in mol%) of (70−z) B2O3–20Li2O–10MgO− zDy2O3 (where 0.05 ≤ z ≤ 0.7 mol%) were prepared via melt-quenching method and subsequently characterized. Radioactive cobalt (Co-60) source was used for irradiations. The optimum dysprosium (Dy...
Source: Radiation Physics and Chemistry - May 13, 2019 Category: Physics Source Type: research

Structural and nuclear radiation shielding properties of bauxite ore doped lithium borate glasses: Experimental and Monte Carlo study
Publication date: Available online 10 May 2019Source: Radiation Physics and ChemistryAuthor(s): E. Kavaz, H.O. Tekin, N. Yıldız Yorgun, Ö.F. Özdemir, M.I. SayyedAbstractIn this work, (Li2B4O7)(100-x) (Bauxite)x (x = 0,10, 20, 30 and 40%) glasses were fabricated by standard melt quenching method. XRD spectra of the glasses were acquired and amorphous structures were verified. The variation of density and molar volume of the bauxite ore doped glasses were examined. The mass attenuation coefficients were measured for 81, 276, 302, 356 and 383 keV of incident photon energies by utilizing transmission method, ...
Source: Radiation Physics and Chemistry - May 12, 2019 Category: Physics Source Type: research

The depth-dose curve depends on the inhomogeneity of the material irradiated by electron beam
Publication date: Available online 10 May 2019Source: Radiation Physics and ChemistryAuthor(s): Nguyen Anh Tuan, Chau Van Tao, Chary RangacharyuluAbstractElectron linear accelerator with average energy 9.92 ± 0.48 MeV, UELR-10-15S2, was set up and operated at the Research and Development Center for Radiation Technology, Vietnam Atomic Energy Institute, for irradiating foods and medical devices directly without X-ray converter. Inside the homogenous products, the depth-dose curve depends on electron beam energy and product density, and moreover, it also depends on the inhomogeneity of the irradiated material. I...
Source: Radiation Physics and Chemistry - May 12, 2019 Category: Physics Source Type: research

Solid standards for positron emitters
Publication date: Available online 10 May 2019Source: Radiation Physics and ChemistryAuthor(s): Mércia L. de Oliveira, Luciane C.O. Reis, Renata L.C. Leão, Maria C.F. Fragoso, Fernando R.A. LimaAbstractHypothesisPositron Emission Tomography is a well establish technique to obtain physiological information of a patient or a process. In order to guarantee all the benefits of this technique it is important to establish quality control routines on the equipment utilized to perform radioactive measurements, the activimeter. In this way, this paper describes the procedure to obtain solid radioactive standard source...
Source: Radiation Physics and Chemistry - May 12, 2019 Category: Physics Source Type: research

Performance evaluation and secondary monitor unit checkout for a dedicated accelerator in intraoperative electron radiotherapy
Publication date: Available online 10 May 2019Source: Radiation Physics and ChemistryAuthor(s): Hamid Reza Baghani, Mostafa Robatjazi, Seyed Rabi MahdaviAbstractQuality assurance in intraoperative electron radiotherapy (IOERT) is a mandatory issue, because of single shot nature. Employed equipment for IOERT implementation, especially the treatment machine, should have a very stable performance for reliable treatment delivery. Calculated MUs is also an important factor which can affect the treatment quality. The aim of this study is to evaluate the performance characteristics of a dedicated accelerator in IOERT as well as a...
Source: Radiation Physics and Chemistry - May 12, 2019 Category: Physics Source Type: research

Gamma photon and neutron attenuation properties of MgO–BaO–B2O3–TeO2–Cr2O3 glasses: The role of TeO2
This study focused on investigation of gamma photon and neutron shielding features of MgO–BaO–B2O3–TeO2–Cr2O3 glass system. The mass attenuation coefficients (MAC) have been calculated at different photon energies between 0.015 MeV and 10 MeV using MCNPX general-purpose of Monte Carlo code. The obtained mass attenuation coefficients have been utilized to evaluate several attenuation parameters such as half value layer (HVL), tenth value layer (TVL), mean free path (MFP) and effective atomic number (Zeff) through these values. Additionally, exposure buildup factor (EBF) values have been calculated ...
Source: Radiation Physics and Chemistry - May 10, 2019 Category: Physics Source Type: research

Analysis of nuclear reactions to determine the radionuclides generated and its activity in various devices
Publication date: Available online 8 May 2019Source: Radiation Physics and ChemistryAuthor(s): José Ródenas, Gumersindo Verdú (Source: Radiation Physics and Chemistry)
Source: Radiation Physics and Chemistry - May 9, 2019 Category: Physics Source Type: research

Fabrication of hexagonally arranged porous carbon films by proton beam irradiation and carbonization
Publication date: Available online 8 May 2019Source: Radiation Physics and ChemistryAuthor(s): Byoung-Min Lee, Van-Tien Bui, Hwa Su Lee, Sung-Kwon Hong, Ho-Suk Choi, Jae-Hak ChoiAbstractHexagonally-arranged porous carbon films (HaPCFs) were prepared by proton beam irradiation and carbonization of hexagonally-arranged porous polystyrene films (HaPPSFs). HaPPSFs prepared by an improved phase separation method were irradiated with 150-keV proton beam at a fluence of 4 × 1016 ions cm−2 to enhance the thermal stability for high-temperature carbonization. Proton beam irradiation of HaPPSFs was found to induce cro...
Source: Radiation Physics and Chemistry - May 9, 2019 Category: Physics Source Type: research

Microbial melanin physiology under stress conditions and gamma radiation protection studies
Publication date: Available online 7 May 2019Source: Radiation Physics and ChemistryAuthor(s): Heba A. El-Bialy, Mammdoh S. El-Gamal, Mohamed A. Elsayed, H.A. Saudi, M.A. KhalifaAbstractAny life-threatening alteration in environmental circumstances from the optimal imposes stress on an organism. Microorganisms possess various strategies, including pigment production, to resist stress conditions in their surrounding environments. In the present study, yeast form of fungus Aureobasidium pullulans either melanized or albino was exposed to different stresses, such as salinity and antifungals (fluconazole, itraconazole, and ter...
Source: Radiation Physics and Chemistry - May 8, 2019 Category: Physics Source Type: research

Improving and optimizing the structure of a cylindrical ionization chamber for radiation protection dosimetry: Guard electrode and chamber wall
Publication date: Available online 7 May 2019Source: Radiation Physics and ChemistryAuthor(s): Hamid Shafaei Douk, Hamed Imani Shirvanedeh, Bagher FarhoodAbstractDue to relative ease, high accuracy, high sensitivity, appropriate response, and other properties of ionization chambers, they are usually employed as reference instruments in dosimetry and quality assurance programs. Therefore, any improvement and optimization in the structure of these dosimeters can lead to accurate measurements of the absorbed dose. In the present study, the structure of a specific cylindrical ionization chamber (PTW, model 23361, Freiburg, Ger...
Source: Radiation Physics and Chemistry - May 8, 2019 Category: Physics Source Type: research

Feasibility of linear diode array based small field data acquisition for 6 MV & 15 MV photon beams – An intercomparison with micro ion chamber
This study aims at evaluating the response of different radiation detectors for measurement of small field radiotherapy beam profiles for high energy photon beams. Micro ion chamber (IC, CC01, IBA) and linear diode array (LDA-99SC, IBA) were used to measure beam data on Siemens ONCOR Impression linear accelerator for 6 MV and 15 MV photon beams. For both detectors the beam profiles were acquired in water phantom for nominal small field sizes ranging from 1 × 1 cm2 to 5 × 5 cm2 at depths of maximum dose (dmax), 5 cm and 10 cm. Measured profiles were inter compared using gamma analysis at pa...
Source: Radiation Physics and Chemistry - May 8, 2019 Category: Physics Source Type: research

Gamma ray shielding properties of heavy-weight concrete containing Nano-TiO2
Publication date: Available online 7 May 2019Source: Radiation Physics and ChemistryAuthor(s): ImanM. Nikbin, Raza Mohebbi, Soudabeh Dezhampanah, Sadegh Mehdipour, Reza Mohammadi, Tahmores NejatAbstractCurrently, application of heavy-weight concrete (HC) as the protective shield against high energy gamma rays, is very popular. Protection against nuclear radiations is one of the most important issues in applied nuclear technology. In the current study, five different concrete mixtures were made using magnetite aggregates and 0, 2, 4, 6 and 8% of titanium oxide (TiO2) nanoparticles. In this research, mechanical properties of...
Source: Radiation Physics and Chemistry - May 8, 2019 Category: Physics Source Type: research

Dose distribution calculation with MCNP code in a research irradiator
Publication date: Available online 6 May 2019Source: Radiation Physics and ChemistryAuthor(s): B. Leal-Acevedo, I. Gamboa-deBuenAbstractBy comparing the data obtained experimentally, the flux density calculations and simulation results using MCNP we can correlate all the results to ensure that the dose imparted to industrial products is appropriate. We have characterized the 3 fields of the irradiator to maximize the volume of irradiation. Percentage discrepancies below 15%, between the data, are due to parameters such as activity per unit length and by comparing line sources (theoretical calculation) and volume sources (s...
Source: Radiation Physics and Chemistry - May 7, 2019 Category: Physics Source Type: research

Determination of the penumbra width of Elekta SRS cone collimator for 6 MV FF and 6 MV FFF energies using gradient-based edge detection
The objective of this work was to apply a Gradient-Based Edge Detection plugin to calculate the penumbra of a radiation beam defined with the Elekta SRS Cone Collimators for beams of 6 MV (Flattening Filter – FF) and 6 MV (Flattening Filter Free – FFF) energies using the beam profile obtained with GafchromicTM film. The results corroborate those from the literature, and they allow a quantitative evaluation of the width of dosimetric penumbra by Gradient-Based Edge Detection. (Source: Radiation Physics and Chemistry)
Source: Radiation Physics and Chemistry - May 7, 2019 Category: Physics Source Type: research

Development of a reconstruction methodology for the X-Ray spectrum of a medical LinAc positioning flat panel
Publication date: Available online 5 May 2019Source: Radiation Physics and ChemistryAuthor(s): Belén Juste, Sergio Morató, Rafael Miró, Ana Isabel Prieto, Gumersindo Verdú, Rafael Genoves, Jose GimenoAbstractThis work analyzes the possibility of using the kV flat panel detector of a medical radiotherapy LinAc for consistency verification of X-ray beam generation in order to perform a quality assurance (QA) protocol. For directly measuring the energy spectrum of X-ray tubes is highly complicated due to the pile up effect produced by the high fluence of photons emitted, we have considered the poss...
Source: Radiation Physics and Chemistry - May 7, 2019 Category: Physics Source Type: research

Study of composition and structure of demineralized bone using X-ray techniques
Publication date: Available online 4 May 2019Source: Radiation Physics and ChemistryAuthor(s): Erika Sales, Cristiane E. Ribeiro da Silva, Sonia Letichevsky, Ramon dos Santos, Luiz A.L. Teixeira Pinto, Claudio T. dos Santos, Luis Fernando de Oliveira, Roberto R. de Avillez, Mauricio Monteiro, Sidnei Paciornik, Marcelino dos AnjosAbstractThe aim of this study is to compare the composition and structure of cortical bones with different stages of in-vitro demineralization from the micro (10–500 μm) to the nano-scale level (below 1 μm) using X-ray techniques, such as Small Angle X-ray Scattering (SAXS), X-ray M...
Source: Radiation Physics and Chemistry - May 6, 2019 Category: Physics Source Type: research

Archeometric study of pottery shards from Conjunto Vilas and São João, Amazon
Publication date: Available online 4 May 2019Source: Radiation Physics and ChemistryAuthor(s): L.S.S. Oliveira, C.M. Abreu, F.C.L. Ferreira, R.C.A. Lopes, F.O. Almeida, E.K. Tamanaha, J.S. Belletti, R. Machado, M.A. Rizzutto, D.N. SouzaAbstractIn this work, we investigated through archeometry studies the mineralogical composition of pottery shards from Conjunto Villas and São João archeological sites located in the macro-region of middle Solimões, in the State of Amazonas, Brazil. Archeometric analyses are fundamental for classification and characterization of ancient ceramics, providing relevant data ...
Source: Radiation Physics and Chemistry - May 6, 2019 Category: Physics Source Type: research

Validation of an automatic eye monitoring system for ocular tumours stereotactic radiotherapy
Publication date: Available online 3 May 2019Source: Radiation Physics and ChemistryAuthor(s): Simone C. Cardoso, Odair D. Gonçalves, Juan V.M. de Sousa, Felipe M.L. de Souza, Dirceu D. PereiraAbstractChoroidal melanoma is a type of tumor that appears in the back of the eye and can rapidly evolve into metastasis. For tumours in advanced stages and/or located near the retina, external beam radiotherapy (teletherapy) is the most used treatment to preserve the patient's eye. The goals of this work are to develop a software for monitoring the patient's eye during the treatment, in order to detect dislocation that could ...
Source: Radiation Physics and Chemistry - May 4, 2019 Category: Physics Source Type: research

The performance of 4H–SiC detector at high temperature after gamma irradiation
Publication date: Available online 3 May 2019Source: Radiation Physics and ChemistryAuthor(s): Zheng Li, Jian Wu, Kunlin Wu, Yikui Fan, Zhongxiong Bai, Yong Jiang, Yanpeng Yin, Qilin Xie, Jiarong LeiAbstractA 4H–SiC detector based on the Schottky diode was fabricated and the combined influence of high temperature and gamma irradiation on 4H–SiC detector has been investigated. We tested the detector's performance at high temperature before gamma irradiation. I–V characteristics and the alpha energy spectra were measured with the 4H–SiC detector before gamma irradiation at high temperature up to 200...
Source: Radiation Physics and Chemistry - May 4, 2019 Category: Physics Source Type: research

Quantitative analysis of the elemental composition of ion liquid with confocal X-ray fluorescence based on peak to background ratio
Publication date: Available online 3 May 2019Source: Radiation Physics and ChemistryAuthor(s): Yufei Li, Xiaoyun Zhang, Yabing Wang, Xuepeng Sun, Zhiguo Liu, Tianxi SunAbstractConfocal X-ray fluorescence (XRF) based on the peak to background ratio was applied to quantitatively analyse the elemental composition of an ion liquid. The confocal micro-volume of the confocal XRF for non-destructive quantitative analysis is often submerged at varying depths in the sample. The modification of the absorption of the detected X-rays coming from the confocal micro-volume submerged at varying depths is complicated. For avoiding complic...
Source: Radiation Physics and Chemistry - May 4, 2019 Category: Physics Source Type: research

EPR dosimetric potential of ammonium oxalate monohydrate in radiation technology
This study aims to examine the dosimetric properties of the ammonium oxalate monohydrate (COONH4)2H2O irradiated by 60Co gamma-rays. The EPR spectra of ammonium oxalate have the spectroscopic splitting g-factors of 2.0095 and 2.0047. Results indicate that the dose-response curves have a good linearity in the range between 10 and 1000Gy. Slight sub-linearity has been found in high dose region up to 25 kGy. The effects of temperature and humidity on the EPR signal amplitude of the irradiated samples were studied. Stability of the irradiation rods upon storage (signal fading) was also investigated. Energy dependence has bee...
Source: Radiation Physics and Chemistry - May 4, 2019 Category: Physics Source Type: research

One-step gamma radiation aided diffusion of Ag-Au alloy nanoparticles into polycarbonate and its application towards the reduction of 4-Nitrophenol
Publication date: Available online 1 May 2019Source: Radiation Physics and ChemistryAuthor(s): K. Hareesh, D.V. Sunitha, Sanjay D. Dhole, Vasanth N. Bhoraskar, Deodatta M. Phase, Jim WilliamsAbstractOne-step gamma radiation aided method was adopted to synthesize face centre cubic structured Silver-Gold alloy nanoparticles (Ag-AuNPs) having particle size ∼10 nm and simultaneously diffused into Polycarbonate (PC). The depth of diffusion of Ag-AuNPs in PC was found to be 93 nm at a dose of 600 kGy. A broad peak around 492 nm in absorbance spectra was due to the surface plasmon resonance of Ag-AuNPs. X-ray Photoe...
Source: Radiation Physics and Chemistry - May 2, 2019 Category: Physics Source Type: research

Insight into restructuring of Pd-Au nanoparticles using EXAFS
Publication date: Available online 29 April 2019Source: Radiation Physics and ChemistryAuthor(s): Alexey Boubnov, Janis Timoshenko, Cody J. Wrasman, Adam S. Hoffman, Matteo Cargnello, Anatoly I. Frenkel, Simon R. BareAbstractWe acquired Pd K-edge and Au L3-edge EXAFS spectra of two libraries of titania-supported Pd-doped Au nanoparticle catalysts representing the as-prepared and post-catalysis state. The nanoparticles have narrow particle size distributions, in the range 2.8–6.6 nm, and were synthesized to preferentially locate the palladium atoms on the surface of a gold core, with Pd mole fractions of 1.4–3...
Source: Radiation Physics and Chemistry - May 1, 2019 Category: Physics Source Type: research

MCMEG: Intercomparison exercise on prostate radiotherapy dose assessment
Publication date: Available online 28 April 2019Source: Radiation Physics and ChemistryAuthor(s): T.C.F. Fonseca, P.C.G. Antunes, M.C.L. Belo, F. Bastos, T.P. Campos, J.M. Geraldo, A.M. Mendes, B.M. Mendes, L. Paixão, P.C. Santana, B. Seniwal, P.L. Squair, H. YoriyazAbstractThe improvement of the Monte Carlo (MC) community skills on computational simulations in Medical Physics is crucial to the field of radiotherapy as well as radiology. The Monte Carlo Modelling Expert Group (MCMEG) is an expert network specialized in MC radiation transport modelling and simulation applied to the radiation protection and dosimetry ...
Source: Radiation Physics and Chemistry - April 29, 2019 Category: Physics Source Type: research

Non-destructive X-ray fluorescence and Raman micro-analytical study of coffee drawings by Lagoa Henriques
Publication date: Available online 28 April 2019Source: Radiation Physics and ChemistryAuthor(s): M. Manso, R. Simão, L. Arruda, M.L. Carvalho, F.A.Baptista PereiraAbstractLagoa Henriques (1923–2009), the well-known Portuguese Sculptor, was also Drawing professor at the Lisbon School of Fine Arts. The sculptor is known for drawing on paper tablecloths during coffee chats. Some of these drawings have become part of the collection of the Faculty of Fine Arts from the University of Lisbon, and like many contemporary artworks that are not carried out with materials conceived for this purpose, pose relevant conserv...
Source: Radiation Physics and Chemistry - April 29, 2019 Category: Physics Source Type: research

Stability of dry phage lambda DNA irradiated with swift heavy IONS
Publication date: Available online 27 April 2019Source: Radiation Physics and ChemistryAuthor(s): M. Yu Karganov, I.B. Alchinova, M.V. Polyakova, V.I. Feldman, S.A. Gorbunov, O.M. Ivanov, R.A. Rymzhanov, V.A. Skuratov, A.E. VolkovAbstractEffects of irradiations of Phage Lambda dry DNA samples at room and cryogenic temperatures with 158 MeV Xe and 48 MeV Ar ions were investigated. These ions primary transfer energy into the electronic subsystem of a target: dE/dx = Se, SeXe = 10.8 keV/nm and SeAr = 3.5 keV/nm. Site-specific enzymes restriction endonucleases were applied to indicate DNA damages induced by...
Source: Radiation Physics and Chemistry - April 28, 2019 Category: Physics Source Type: research

The DSM theory for tip electron-atom bremsstrahlung at 5 − 500 MeV
Publication date: Available online 27 April 2019Source: Radiation Physics and ChemistryAuthor(s): D.H. Jakubassa-AmundsenAbstractThe Dirac–Sommerfeld-Maue (DSM) theory for electron bremsstrahlung at the short-wavelength limit, based on a point-Coulomb description of the target nucleus, is tested against the Dirac partial-wave (DW) theory at collision energies up to 35 MeV. It is found that for the small photon angles, which contribute to the angle-integrated bremsstrahlung yield, the screening effects are at most in the percent region. Predictions are made for the nuclear charge dependence of the singly differentia...
Source: Radiation Physics and Chemistry - April 28, 2019 Category: Physics Source Type: research

Comparative analysis of the transmission properties of tissue equivalent materials
Publication date: Available online 27 April 2019Source: Radiation Physics and ChemistryAuthor(s): Bruna C. Nascimento, Audrew Frimaio, Ramon M.M. Barrio, Ana C.A. Sirico, Paulo R. CostaAbstractPhantom objects have as main requirement to have the effective atomic number and linear attenuation coefficient approximately equal to the human tissue to be simulated. The present work aims to characterize samples of materials radiologically equivalent to water for dose studies in patients in the diagnostic energy range. Water was chosen as reference material representing human tissue, which is composed mostly of it. A set of sample...
Source: Radiation Physics and Chemistry - April 28, 2019 Category: Physics Source Type: research

Impact of γ− irradiation on the physico-chemical, rheological properties and in vitro digestibility of kithul (Caryota urens) starch; a new source of nonconventional stem starch
Publication date: September 2019Source: Radiation Physics and Chemistry, Volume 162Author(s): Cherakkathodi Sudheesh, Kappat Valiyapeediyekkal Sunooj, Johnsy George, Sunny Kumar, Vikas, Vallayil Appukuttan SajeevkumarAbstractKithul (Caryota urense) starch was exposed to gamma irradiation at different doses (0.5 kGy, 1 kGy, 2.5 kGy, 5 kGy, 10 kGy). Its impact on physico-chemical, morphological, rheological properties and in vitro digestibility of kithul starch was studied. Irradiation decreased the pH, swelling index, amylose and moisture content of kithul starch and increased the carboxyl content, acidity, solubi...
Source: Radiation Physics and Chemistry - April 28, 2019 Category: Physics Source Type: research

Particle size effect on fluorescence emission for Au-infused soft tissues
Publication date: Available online 26 April 2019Source: Radiation Physics and ChemistryAuthor(s): Bryan Casanelli, Mauricio Santibáez, Mauro ValenteAbstractThe use of high atomic number micro- and nano-particles has been widely extended in biomedical applications. As known, particle size strongly determines most of physical and functional properties when these are infused within biological systems. Monte Carlo simulations are one of the most commonly used tools to investigate physical processes involved in these particle infused systems aimed at radiosensitivity enhancement or theranostic purposes. In this context, ...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

Survey of paediatric imaging exposure from computed tomography examinations
The objective of this study has been investigation of paediatric patient doses received in Saudi Arabia during CT examinations of the brain, abdomen and chest, comparison of these being made with international standards, guided by Dose Reference levels (DRLs). The study includes data from a total of 59 patients from three hospitals, the mean age and age range of the paediatric cases being 5.10 (0.01–13) years, mean weight and weight range 20 (3–40) kg. The range of DLP (mGy.cm) per procedure was 113–995, 54–1244 and 30.0–190.0 for brain, abdomen and chest procedures, respectively. DRLs were pr...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

Monte Carlo simulation of hybrid pixel detectors
Publication date: Available online 26 April 2019Source: Radiation Physics and ChemistryAuthor(s): D.P. Magalhaes, A. TomalAbstractSemiconductor sensors are extensively used for X-ray detection, both for spectroscopy and 2D imaging. In this work, the Monte Carlo code PENELOPE v. 2014 with the PenEasy v. 2015 extension was applied for simulating a Medipix3RX detector from sensor to ASIC. The code was modified to include the charge dispersion effect modelling at the Pixelated Imaging Detector tally, and validated by investigating the influence of the electric field, incident energy, beam position, pixel size and also by deter...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

New technologies for carbon-ion radiotherapy — Developments at the National Institute of Radiological Sciences, QST, Japan
Publication date: Available online 25 April 2019Source: Radiation Physics and ChemistryAuthor(s): Nobuyuki Kanematsu, Takuji Furukawa, Yousuke Hara, Taku Inaniwa, Yoshiyuki Iwata, Kota Mizushima, Shinichiro Mori, Toshiyuki ShiraiAbstractThe National Institute of Radiological Sciences in Japan started clinical studies of carbon-ion radiotherapy (CIRT) in 1994. Due to the high linear energy transfer (LET) of highly charged particles, carbon-ion beams show high relative biological effectiveness (RBE) in cell killing, especially at the Bragg peak of dose near the beam range, which is controlled to conform to a tumor. Recent te...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

Post-effects of radioactive decay in ligands on biologically active transport platforms
Publication date: Available online 25 April 2019Source: Radiation Physics and ChemistryAuthor(s): Igor Alekseev, Aleksandr Miroslavov, Ekaterina StepanovaAbstractThe electron capture consequences in the 57Co DOTA complex compound and processes of radiation-induced defect formation in DOTA under the effect of recoil nuclei produced after the α-decay of 241Am were studied using high performance liquid radiochromatography and emission Mössbauer spectroscopy. The experiments conducted have shown that the production of targeted RPHs on the base of alpha-emitters and when applying the conventional approach (biological...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

On higher–order corrections to nuclear bremsstrahlung cross sections
Publication date: Available online 25 April 2019Source: Radiation Physics and ChemistryAuthor(s): A. Mangiarotti, D.H. Jakubassa-Amundsen, M.N. MartinsAbstractA quantitative understanding of bremsstrahlung by electrons in the screened field of atomic nuclei has been developed by several researchers over the last 80 years. However, some ranges of the possible parameters still can not be covered with good accuracy. Dirac partial-wave calculations are the best method developed to date, while analytic calculations are the only viable solution at high impinging electron energies. Recent progresses on both fronts will be discuss...
Source: Radiation Physics and Chemistry - April 27, 2019 Category: Physics Source Type: research

Comparative study of different chitosan solutions to assist the green synthesis of gold nanoparticles under irradiation
Publication date: Available online 24 April 2019Source: Radiation Physics and ChemistryAuthor(s): Thananchai Piroonpan, Pichayada Katemake, Wanvimol PasanphanAbstractDifferent chitosan aqueous solutions, i.e., conventional chitosan in acetic acid (CTS-HOAc) and non-derivatized water-soluble chitosan (WSCTS) were used as polymer templates for a green synthesis of gold nanoparticles (AuNPs) under gamma irradiation. Because of molecular template effect, the CTS-HOAc and WSCTS exhibited different performance for AuNPs synthesis under various irradiation doses and HAuCl4 precursor concentrations. The AuNPs formation in WSCTS an...
Source: Radiation Physics and Chemistry - April 25, 2019 Category: Physics Source Type: research