scholarly journals Investigation of the electron paramagnetic resonance signal response in gamma-irradiated poly(lactic acid) for high-dose dosimetry

2018 ◽  
Vol 64 (5) ◽  
pp. 472
Author(s):  
Fernando Ureña-Núñez ◽  
Salvador Galindo
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Lactic Acid ◽  
Gamma Ray ◽  
Detection Threshold ◽  
Poly Lactic Acid ◽  
High Dose ◽  
Paramagnetic Resonance ◽  
Epr Signal ◽  
Signal Response ◽  
Electron Paramagnetic

This paper is concerned with the investigation of the Electron Paramagnetic Resonance (EPR) signal response to Co60 gamma-ray radiation on poly(L-lactic acid) (PLA). The aim of this study is to assess the usefulness of PLA as a high-dose dosimeter. The EPR-signal response of PLA has been investigated to determine some of its dosimetric characteristics such as: signal intensity versus gamma dose received, zero-dose response, signal fading, signal repeatability, batch homogeneity, detection threshold, and stability under simulated sunlight exposure. It is concluded that PLA might be used as a high-dose dosimeter.

scholarly journals Synthesis, processing and electron paramagnetic resonance response of Y1.98Eu0.02O3 micro rods

2018 ◽  
Vol 48 ◽  
pp. 1860112
Author(s):  
S. C. Santos ◽  
O. Rodrigues ◽  
L. L. Campos
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Rare Earth ◽  
Yttrium Oxide ◽  
Radiation Dosimetry ◽  
Promising Material ◽  
Paramagnetic Resonance ◽  
Epr Signal ◽  
Signal Response ◽  
Electron Paramagnetic ◽  
Dosimetric Materials

Innovating dosimetric materials, which includes design and development of new dosimetric materials based on rare earth oxides, is challenging. Yttrium oxide (Y[Formula: see text]O[Formula: see text] is one of the most important sesquioxides and presents crystal characteristics that enable doping with rare earth ions, making it a promising material for radiation dosimetry. This paper reports on the development and measurement of Electron Paramagnetic Resonance (EPR) signal response for Y[Formula: see text]Eu[Formula: see text]O[Formula: see text][Formula: see text]micro rods that have undergone facile low-pressure hydrothermal synthesis and bio-prototyping. As- synthesized powders with narrow sub-micrometer particle size distribution with d[Formula: see text][Formula: see text] of 584 nm exhibited a reactive surface, which led to the formation of stable aqueous suspensions by controlling the surface charge density of particles through alkaline pH adjustment. Ceramic samples with dense microstructure were formed by sintering at 1600 [Formula: see text]C for 4h at ambient atmosphere. Y[Formula: see text]Eu[Formula: see text]O[Formula: see text][Formula: see text]micro rods were irradiated using a [Formula: see text]Co source with doses from 1 to 100 kGy, and EPR spectra were measured at room temperature in X-band microwave frequencies. Sintered samples exhibited linearity of the main EPR signal response from 10 Gy to 10 kGy. Supralinearity was observed for higher doses, which is possibly ascribed to formation of more defects. Using europium as a dopant enhanced the EPR signal of yttrium rods remarkably, due to 4f–4f transitions of the Eu[Formula: see text] ion. These innovative findings make europium-doped yttrium oxide a promising material for radiation dosimetry.

Room Temperature Electron Paramagnetic Resonance (EPR) Signal Storage

1969 ◽  
Author(s):  
D.A. Bozanic ◽  
D.C. Buck ◽  
F.H. Harris ◽  
R.E. Huber ◽  
D. Mergerian ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Temperature Electron ◽  
Epr Signal ◽  
Electron Paramagnetic

Quantification of mobilized copper(II) levels in micronized copper-treated wood by electron paramagnetic resonance (EPR) spectroscopy

Holzforschung ◽  
2013 ◽  
Vol 67 (7) ◽  
pp. 815-823 ◽  
Author(s):  
Wei Xue ◽  
Pierre Kennepohl ◽  
John N.R. Ruddick
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Epr Spectroscopy ◽  
Treated Wood ◽  
Spectral Parameters ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Acid Reaction ◽  
Epr Signal ◽  
Electron Paramagnetic ◽  
Reference Samples

Abstract Sapwood sawdust from southern pine was treated with micronized copper (MC) under various conditions and the mobilized copper(II) (Cumob) concentrations were determined in the treated wood by electron paramagnetic resonance (EPR) spectroscopy. The spectral parameters for the copper sulfate (CuSO4)-treated sapwood and those of the MC-treated sapwood were very similar. A linear correlation was found between the intensities of copper (Cu) EPR spectra and those of Cu energy-dispersive X-ray fluorescence spectroscopy in a series of CuSO4-treated sapwood reference samples. Thus, the EPR signal intensities could be reliably correlated to the mass of reacted Cu present using this calibration curve. The amount of the Cumob in sawdust treated by MC suspensions increased during the first 2–3 days after the initial treatment and then reached a maximum during the 7-day monitoring period. In the case of the treatment with MC alone or MC azole, an increased MC concentration led to an elevated amount of Cu (to a maximum of ∼0.23% Cu) solubilized by the sapwood. If the wood was treated with MC quat, the Cumob initially increased, but at higher concentrations the Cumob content decreased, due to the interference by the quat cobiocide on the acid reaction between the wood and the basic Cu carbonate. An examination of commercially-treated wood confirmed the laboratory observations.

scholarly journals DEPENDENCE OF ELECTRON PARAMAGNETIC RESONANCE (EPR) SPECTRUM PARAMETERS ON THE KIND OF MEAT AND FISH TREATED BY IONIZING RADIATION

2018 ◽  
Vol 97 (9) ◽  
pp. 873-876
Author(s):  
R. T. Timakova ◽  
Sergei L. Tikhonov ◽  
O. V. Evdokimova ◽  
I. V. Butenko
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ionizing Radiation ◽  
Bone Tissue ◽  
Radiation Treatment ◽  
Raw Materials ◽  
Food Products ◽  
Epr Spectrum ◽  
Paramagnetic Resonance ◽  
Epr Signal ◽  
Electron Paramagnetic

Regulation of the use of ionizing radiation for treating food products and agricultural raw materials in Russia in 2017 suggests a wide dissemination of radiation technologies in the food industry, but manufacturers of food products processed by ionizing radiation do not indicate on the label the relevant information. Because of this, the identification of the domestic consumer market of food products processed by ionizing radiation will reduce the number of violations of requirements of state standard State standards (GOST) 33800-2016 “Production of food irradiated. General labeling requirements”. To determine whether irradiation of food raw materials and foodstuff, used the method of electron paramagnetic resonance (EPR), with each of the food products treated by ionizing radiation has its own characteristic EPR spectrum. In this regard, the aim of the research is to identify the dependence of the parameters of the EPR spectrum from meat, fish and poultry treated with ionizing radiation. Samples of bone tissue (SBT) meat, fish and poultry were subjected to radiation treatment with a linear electron accelerator model UELR-10-10С2 with energies up to 10 MeV. Studies of samples were carried out on the portable automated EPR spectrometer brand Labrador Expert X-band. Found that despite treatment samples of bone tissue with the same dose of ionizing radiation (12 kGy), the EPR signal depends on the type of vertebrates, the structure of the tissue sample, and other factors. Bone samples of beef and pork have a higher sensitivity to irradiation. Recorded a steady correlation between increasing the area of the EPR signal parameters: amplitude is of 0.99, the width of the peak signal, respectively 0,979 (the degree of strength of statistical relationships Chedoke very high). Processing of the obtained results of the EPR spectrum provides a high degree of confidence (p≤0.05) to identify how previously non-irradiated and radiation-processed various meats, fish and poultry.

Electron Paramagnetic Resonance Study of Ion-Implanted Photorefractive Crystals

1997 ◽  
Vol 504 ◽  
Author(s):  
A. Darwish ◽  
D. Ila ◽  
E. K. Willams ◽  
D. B. Poker ◽  
D. K. Hensley
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ion Implantation ◽  
Room Temperature ◽  
Electron Paramagnetic Resonance Study ◽  
Paramagnetic Resonance ◽  
Photorefractive Crystals ◽  
Laser Illumination ◽  
Epr Signal ◽  
Electron Paramagnetic

ABSTRACTThe effect of the ion implantation (Fe) on LiNbO3, MgO, and A12O3 crystals is studied using electron paramagnetic resonance (EPR). EPR measurements on these crystals were performed as a function of fluence at room temperature. The fluence was 1 × 1014 and 1 × 1016 ions/cm2. The unpaired carrier concentration increases with increasing fluence. The photosensitivity of these crystals was determined by observing in situ the effect of the laser illumination on the EPR signal and measuring the decay and the growth of the EPR signal. The EPR signal of Fe3+ was found to decrease in both MgO, and Al2O3; and was found to increase in LiNbO3. This indicated that in case of MgO, and A12O3 Fe3+ will transfer into Fe2+/Fe4+, but in case of LiNbO3 Fe2+/ Fe4+ will transfer into Fe3+; increasing the EPR signal. This was found primary due to some Fe2+ and Fe4+ ions, which is not intentionally doped on the LiNbO3 crystal but exist as a defect on the crystal.

scholarly journals The Carbon Vacancy Related EI4 Defect in 4H-SiC

2010 ◽  
Vol 645-648 ◽  
pp. 399-402 ◽  
Author(s):  
Nguyen Tien Son ◽  
Patrick Carlsson ◽  
Junichi Isoya ◽  
Norio Morishita ◽  
Takeshi Ohshima ◽  
...  
Keyword(s):  
Electron Paramagnetic Resonance ◽  
High Purity ◽  
Room Temperature ◽  
Paramagnetic Resonance ◽  
Annealing Behaviour ◽  
Carbon Vacancy ◽  
Epr Signal ◽  
Electron Paramagnetic

Electron paramagnetic resonance (EPR) was used to study high-purity semi-insulating 4H-SiC irradiated with 2 MeV electrons at room temperature. The EPR signal of the EI4 defect was found to be dominating in samples irradiated and annealed at ~750°C. Additional large-splitting 29Si hyperfine (hf) lines and also other 13C and 29Si hf structures were observed. Based on the observed hf structures and annealing behaviour, the complex between a negative carbon vacancy-carbon antisite pair (VCCSi–) and a distance positive carbon vacancy ( ) is tentatively proposed as a possible model for the EI4 defect.

Pl And Epr Spectroscopy Of Point Defects In Detector-Grade Cd1−xZnxTe

1997 ◽  
Vol 487 ◽  
Author(s):  
C. I. Rablau ◽  
S. D. Setzler ◽  
L. E. Halliburton ◽  
F. P. Doty ◽  
N. C. Giles
Keyword(s):  
Point Defects ◽  
Room Temperature ◽  
Gamma Ray ◽  
Paramagnetic Resonance ◽  
X Ray ◽  
Shallow Donors ◽  
Shallow Acceptors ◽  
Epr Signal ◽  
And Control ◽  
Electron Paramagnetic

AbstractCadmium zinc telluride (CdZnTe) is an emerging material for room-temperature x-ray and gamma ray detectors. The identification and control of point defects and charge compensators are currently important issues. Low-temperature photoluminescence (PL) and electron paramagnetic resonance (EPR) spectroscopies have been used to characterize point defects in CdZnTe crystals grown by the high-pressure Bridgman technique. Luminescence due to shallow donors, shallow acceptors, and deeper acceptors was monitored for a series of samples. An isotropic EPR signal attributed to shallow hydrogenic donors is observed in all samples, and the concentration of shallow donors has been determined. The nature of the defect centers (impurities, vacancies, vacancy-impurity complexes), and the correlation between defect concentration and device performance is discussed.

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