Search results for "gamma radiation"
showing 10 items of 11 documents
Effects of radiation and hydrogen-loading on the performances of raman-distributed temperature fiber sensors
2015
International audience; The integration of Raman-distributed temperature fiber-based sensors (RDTS) into the envisioned French deep geological repository for nuclear wastes, called Cigéo requires evaluating how the performances of RDTS evolve in harsh environments, more precisely in presence of H2 or γ-rays. Both H2 and radiations are shown to affect the temperature measurements made with the single-ended RDTS technology. The amplitudes of the observed effects depend on the different classes of multimode fibers varying in terms of composition and coatings. By selecting the most tolerant fiber structure for the sensing, we could maintain the RDTS performances for such application. A hardeni…
Radiation-tailored xyloglucan-doxorubicin nanoparticles for cancer therapy
2022
Polysaccharides are long chains of monosaccharides linked by glycosidic bonds. They are widely utilized in biomedical applications, for tissue engineering and wound management, and as excipients of pharmaceutical formulations. In cancer therapy, the development of nanoscale drug delivery systems aims at addressing issues related to the low efficacy of chemotherapeutics and protein drugs due to poor solubility and stability, and to off-target effects that severely affect patients’ body conditions. Biocompatibility, availability of functional groups, amenability of chemical derivatisation and multifunctional conjugation with drugs and targeting ligands make polysaccharide nanoparticles intere…
Gamma radiation of EVA-AA/MMA swollen systems to obtain mechanically improved blends
2002
In this work a "new" way to obtain "compatibilised" blends of rubber-glassy thermoplastic components is presented. Polyethylen-vinyl acetate acrylic acid terpolymer is swollen by methylmetacrylate and the system is irradiated through gamma rays in order to induce polymerisation of the monomer. Solubility and dynamic mechanical tests indicate the formation of a two phase system, even though in presence of strong interactions between the two components. Mechanical tensile behaviour is that of a ductile material with appreciable modulus values.
Concentration-Dependent Protection by Ethanol Extract ofPropolis against γ
2011
[EN] Radioprotection with natural products may be relevant to the mitigation of ionizing radiation-induced damage in mammalian systems; in this sense, propolis extracts have shown effects such as antioxidant, antitumoral, anti-inflammatory, and immunostimulant. We report for the first time a cytogenetic study to evaluate the radioprotective effect, in vitro, of propolis against radiation-induced chromosomal damage. Lymphocytes were cultured with increasing concentrations of ethanol extract of propolis (EEP), including 20, 40, 120, 250, 500, 750, 1000, and 2000 ¿g mL-1 and then exposed to 2 Gy ¿-rays. A significant and concentration-dependent decrease is observed in the frequency of chromoso…
Steady state γ-ray radiation effects on Brillouin fiber sensors
2015
International audience; Brillouin optical time-domain analysis (BOTDA) sensors offer remarkable advantages for the surveillance of the planned French deep geological radioactive wastes repository, called Cigéo1,2. In this work we study the performances of Brillouin distributed sensors in harsh environment. We evaluate the radiation tolerance of different sensor classes and their responses evolution during γ-ray exposition with 1kGy/h dose rate (to reach ~0.2MGy) and after 1, 3, 6 and 10 MGy accumulated doses. Measurements on strained Ge-doped SMF are reported to highlight the variation on Brillouin scattering proprieties, both intrinsic frequency position of Brillouin shift and its dependen…
EPR DOSIMETRY IN A MIXED NEUTRON AND GAMMA RADIATION FIELD
2004
Suitability of Electron Paramagnetic Resonance (EPR) spectroscopy for criticality dosimetry was evaluated for tooth enamel, mannose and alanine pellets during the 'international intercomparison of criticality dosimetry techniques' at the SILENE reactor held in Valduc in June 2002, France. These three materials were irradiated in neutron and gamma-ray fields of various relative intensities and spectral distributions in order to evaluate their neutron sensitivity. The neutron response was found to be around 10% for tooth enamel, 45% for mannose and between 40 and 90% for alanine pellets according their type. According to the IAEA recommendations on the early estimate of criticality accident a…
Fogging effect correction of Gafchromic HD-V2 film response for its use in high-dose radiotherapy
2020
GAFChromic® HD-V2 film is a reliable dose measurement device, thin, flexible, inexpensive, simple to use and easy to analyze. The response in terms of net absorbance with respect to absorbed dose was found to be linear in a large dose range, which supports the feasibility of using the film dosimeters in many applications, such as radiotherapy. For its use, a "fogging" effect must be take into account since film response changes with time. To determine a calibration curve valid for any time, fogging effect was investigated for more than 400 days. A correction procedure allows the use of HD-V2 film dosimeters in high-dose radiotheraphy, as brachytherapy, and quality assurance (QA) procedures.
Evaluation of Distributed OFDR-Based Sensing Performance in Mixed Neutron/Gamma Radiation Environments
2017
We report the study of a radiation resistant single mode optical fiber doped with fluorine exposed to mixed neutron and $\gamma $ -radiation up to $10^{17}$ n/cm2 fluence and >2 MGy dose to evaluate its performances when used as the sensing element of a distributed Optical Frequency Domain Reflectometry (OFDR). The use of complementary spectroscopic techniques highlights some differences between the responses of solely $\gamma $ -radiation (10 MGy) or mixed neutron and $\gamma $ ( $10^{17}$ n/cm $^{2}+>2$ MGy) irradiated samples. Those differences are linked to the defect generation rather than to structural changes of the ${a}$ -SiO2 host matrix. We show that a modification of the refracti…
Investigation of the Efficiency of Shielding Gamma and Electron Radiation Using Glasses Based on TeO2-WO3-Bi2O3-MoO3-SiO to Protect Electronic Circui…
2022
This research was funded by the Science Committee of the Ministry of Education and Science of the Republic of Kazakhstan (No. AP09058081). EP, EE, and AIP thank the Institute of Solid State Physics, University for their support. ISSP UL as the Center of Excellence is supported through the Framework Program for European universities Union Horizon 2020, H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, CAMART2 project.
Gamma rays as probe of fission and quasi-fission dynamics in the reaction 32S + 197Au near the Coulomb barrier
2017
International audience; Compound nucleus fission and quasi-fission are both binary decay channels whose common properties make the experimental separation between them difficult. A way to achieve this separation could be to probe the angular momentum of the binary fragments. This can be done detecting gamma rays in coincidence with the two fragments. As a case study, the reaction 32S + 197Au near the Coulomb barrier has been performed at the Tandem ALTO facility at IPN ORSAY. ORGAM and PARIS, two different gamma detectors arrays, are coupled with the CORSET detector, a two-arm time-of-flight spectrometer. TOF-TOF data were analyzed to reconstruct the mass-energy distribution of the primary …