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Most particle detectors are based on the hypothesis that particles are emitted randomly upon nuclear decay. In the present work, we tested the hypothesis of the existence of correlation in the random trajectories of alpha particles emitted from 241 Am source and the null hypothesis of random trajectories. The trajectories were clued through the registration of track in a solid-state nuclear track detector. The experimental parameters were optimized to identify the possible sources of correlation in the track registration and the detector conditions upon exposure and etching to avoid misleading results. The optimization included authentication of linearity in registration efficiency with exposure time to prevent coalescence of registered tracks. The statistical inference processes were based upon adaptive quadrates analysis of the spatial data, and entropy and divergence analysis of the quadrate data together with the null hypothesis of Poisson distribution of random trajectories. The clustering and dispersion analysis were performed with central deviation tendency, empirical K-function, radial distribution analysis, and proximity Analysis. Results showed a pattern of gained information within the registered tracks that may be attributed to the alteration in the alpha particles' trajectories induced by the strong electric field due to atoms in the source compound and encapsulation film. [ABSTRACT FROM AUTHOR]

In this work, the response of the CR-39 nuclear track detector (NTD) exposed to different low doses of gamma rays was investigated using UV–Vis and photoluminescence spectroscopy. Five NTDs of CR-39 were irradiated with low gamma-ray doses ranging from 10 to 120 kGy using a60Co source. The dose of gamma rays correlates with red shift in the absorption spectra of a gamma-irradiated CR-39 detector. As the gamma dose increases, the indirect and direct energy band gaps, as well as Urbach energy, decrease gradually. However, the decrease in the indirect optical band gap is greater than the decrease in the direct band gap. The observed spectra of the CR-39 detector after being irradiated with different doses of γ-rays showed an acceptable variation in photoluminescence (PL) emission spectra generated by a well-defined excitation wavelength of 290 nm. Starting at 45 kGy dose, the integrated area of the photoluminescence peak increases and tends to saturate, whereas the photoluminescence peak height is linearly correlated with the gamma dose with high sensitivity, which is 53.1 ± 6.3 CPS. kGy−1. According to the current findings, photoluminescence (PL) spectroscopy has a greater sensitivity than UV–Vis spectroscopy for measuring the response of the CR-39 detector to gamma rays in the dose range of 10–120 kGy. The results reflected a potential possibility of using the CR-39 detector in dosimetric applications of low gamma ray doses through the high resolution achieved by photoluminescence (PL) and UV–Vis spectroscopy. • CR-39 NTDs is applied in low doses gamma ray dosimetry. • UV–Vis spectra are red shifted as gamma ray dose increase from 10 to 120 kGy. • Photoluminescence (PL) emission spectra is generated excitation wavelength of 290 nm. • Photoluminescence (PL) is of higher sensitivity than UV–Vis spectroscopy. • The photoluminescence peak height is linearly correlated with the gamma dose. [ABSTRACT FROM AUTHOR]

The color channel's effect on the dose-response of Gafchromic™ EBT2 and EBT3 radiochromic films irradiated with a 6 MeV electron beam in the range from 0 to 1000 cGy was investigated and compared. A Canon flatbed scanner was used to scan the irradiated Gafchromic™ EBT2 and EBT3 films, while ultraviolet-visible (UV-Vis) absorption spectra were analyzed with a spectrophotometer. Triple RGB channel, weighted and unweighted grey images were analyzed using the free software ImageJ. As the 6 MeV electron beam dose increases, the pixel values of the red, green, weighted, and unweighted grey images decrease exponentially for both Gafchromic™ EBT2 and EBT3 films. The blue channel fluctuates with the increase of 6 MeV electron beam dose for both EBT2 and EBT3 films and decreases the unweighted grey image more than the weighted greyscale image. The characteristic peaks at 582 ± 2 nm and 632 ± 2 nm of Gafchromic™ EBT2 and EBT3 films are correlated with the absorbed 6 MeV electron beam dose. The sensitivity deterioration constant b 3 (is a free parameter of fitting in units of (cGy−1)) of EBT2 film is higher than EBT3 at both characteristic peaks at 582 ± 2 nm, and 632 ± 2 nm, indicating that EBT2 has better sensitivity at the expense of dynamic range, whilst EBT3 has lower sensitivity but a higher dynamic range. In comparison to the red and green channels, UV-Vis absorption in the blue channel range between 450 nm and 490 nm has a weak response and a small dynamic range. The Gafchromic™ EBT2 and EBT3 films scan with monochromatic red or green channels resulting in increased sensitivity and a wider dynamic range. • The Blue channel fluctuates with dose increase, affecting unweighted grey image more than weighted greyscale image. • UV-Vis absorption in blue channel range has weak response and small dynamic range. • Characteristic peaks at 582 ± 2 nm and 632 ± 2 nm correlate with absorbed 6 MeV electron beam dose. • EBT2 has better sensitivity but lower dynamic range, whilst EBT3 has lower sensitivity but higher dynamic range. [ABSTRACT FROM AUTHOR]

Cross sections for electron-impact detachment and electron-impact dissociation of NCO- and NCS- were measured from about 3 to about 40 eV. The former are found to follow a classical prediction with a threshold energy of 9.1±0.1 eV for NCO- and 8.9±0.2 eV for NCS-. When the incoming electron binds to the monoanion, a short-lived dianion complex is formed, which is revealed as a resonance in the cross section. For NCO- a resonance is evident at 9.3±0.2 eV, which implies that the dianion lies above the monoanion by this amount of energy. In the case of NCS- two resonances are evident at 8.4±0.2 and 19.0±0.5 eV, respectively. The low-energy NCS dianion is less unstable than the dianion of NCO, which in turn is less unstable than the CN dianion (10-eV resonance). Thus the resonance shifts down in energy with the increasing size of the anion, a fact which is attributed to a decrease in Coulomb energy between the spatially separated electrons. [ABSTRACT FROM AUTHOR]

Makrofol ® DE 1-1 (bisphenol-A polycarbonate) was investigated for alpha particle radiography. The edge spread function (ESF) was measured by razor-blade's edge. Makrofol ® DE 1-1 detectors were irradiated with perpendicular incident alpha particles of energy 2.5, 4 and 5.4 MeV, thereafter they were etched in 75% 6N KOH+25% C 2 H 5 OH at a temperature of 50 °C for different durations. The etched Makrofol®DE 1-1 detectors were imaged with an optical microscope equipped with a CCD camera. The results revealed that the green channel of the original RGB image provides the highest contrast comparing with red and blue channel by a factor of 27.6% of the original RGB image. The image contrast of alpha particle-irradiated Makrofol®DE 1-1 detector was found to be inversely related to the etching time since the alpha particle tracks proceed from a conical phase to spherical phase. The spatial resolution of alpha particle-irradiated Makrofol®DE 1-1 detector, in terms of line spread function, was found to deteriorate as the etching time increases for all examined alpha particle energies. The results revealed the potential capability of Makrofol®DE 1-1 detector as an efficient detector for alpha particle radiography such as autoradiography. [ABSTRACT FROM AUTHOR]

The activation and deactivation of photochromic TRANSITIONS SIGNATURE® VII lens under extreme exposure to ultraviolet radiation of 222 W/m2 for more than 144 h are scrutinized. The photoluminescence (PL) spectra upon excitation with ultraviolet radiation of different wavelengths have been investigated. The obtained results show that photochromic TRANSITIONS SIGNATURE® VII gray lenses blocked ultraviolet radiation from 190 nm to 400 nm. The absorbance increases from 0.021 to be about 0.44 upon exposure to ultraviolet radiation of 302 nm for 144 h. The deactivation rate is decreasing exponentially with elapsed time; the absorbance reduces to be half after 5 min. Under extreme exposure to ultraviolet radiation of 302 nm the lens transmittance dynamic range reduces from 21.10 to be 7.20, also the optical band gap is insignificantly decreased from 2.913 eV to 2.869 eV indicating that the lens is non-degradable. TRANSITIONS SIGNATURE® VII lens was irradiated with ultraviolet radiation in the wavelength range from 260 to 400 nm and the photoluminescence (PL) emission spectra were measured. A strong correlation between the PL spectra and the excitation wavelength of ultraviolet radiation was observed. Both the PL integrated area under the peak and its band peak height are associated with the excitation wavelength, peaking at 275 nm and 385 nm, respectively, and then decreasing as the ultraviolet radiation wavelength increased. These results demonstrate that TRANSITIONS SIGNATURE® VII lenses are resistant to all ultraviolet radiation as well as blue light where Chromea7™ is activated. • The response of photochromic TRANSITION SIGNATURE® VII lens upon extreme exposure to ultraviolet radiation is scrutinized. • TRANSITION SIGNATURE® VII lens is non-degradable under extreme exposure to ultraviolet radiation. • The deactivation half life time of TRANSITION SIGNATURE® VII lens is 5 min. • The photoluminescence (PL) spectra as a function of wavelength have been investigated. • TRANSITION SIGNATURE® VII lenses are resistant to ultraviolet radiation as well as blue light where chromea7 is activated. [ABSTRACT FROM AUTHOR]

The response of Gafchromic™ EBT2 film selectively to UVA solar radiation was studied. A set of EBT2 films was exposed from the topside (80 μm) and the other set from the polyester substrate (175 μm) for different durations. The EBT2 topside components absorb wavelengths shorter than 400 nm, while the polyester substrate absorbs wavelengths shorter than 315 nm. Accordingly, EBT2 film can detect solar UVA radiation (315–400 nm) by calculating the difference (net change) between the irradiated sets. For EBT2 film exposed from polyester substrate, the red, green and grey color channels are decay exponentially with exposure time, where the green color channel has the highest sensitivity. When EBT2 film is exposed from the topside, red, green and grey color channels are linearly correlated with exposure time, but showing poor sensitivity. For EBT2 exposed from topside, the absorbance peaks at 580 ± 2 nm and 632 ± 2 nm are slightly increasing with the increase in the exposure time, while for EBT2 films exposed from polyester substrate; the characteristic peaks are correlated exponentially with exposure time and saturated after 80 min. The net effect of solar ultraviolet UVA radiation on EBT2 films increases exponentially with exposure time with tendency to saturate at prolonged exposure. It is found that the EBT2 films digitization with flatbed scanner has a higher sensitivity but a narrower dynamic range, while analysis with UV–Vis spectrophotometer has lower sensitivity but a wider dynamic range. This new findings pave the way to measure UVA radiation (315–400 nm) using a simple equipment including Gafchromic™ EBT2 film and flatbed scanner. • Absorption of electromagnetic waves by GafchromicTM EBT2 radiochromic film's components is ascertained. • The topside components of Gafchromic™ EBT2 radiochromic film absorb UVA radiation completely. • UVA solar radiation (315–400 nm) can be detected using Gafchromic™ EBT2 film and flatbed scanner. • EBT2 films digitization with flatbed scanner has a higher sensitivity but a narrower dynamic range. [ABSTRACT FROM AUTHOR]

Electronimpact dissociation of protonated and deuterated nitrogen ions hasbeen studied using a crossed beams apparatus. Absolute cross sectionsfor dissociation channels producing N+and NH+, respectively, are presented. The observations of subthreshold signalsin these measurements indicate the presence of ro-vibrationally andpossibly electronically excited states in the parent ions. Comparisonswith other measurements are given. [ABSTRACT FROM AUTHOR]

The induced photoluminescence (PL) from the π-conjugated polymer poly allyl diglycol carbonate (PADC) (CR-39) upon excitation with the ultraviolet radiation of different wavelengths was investigated. The absorption and attenuation coefficients of PADC (CR-39) were recorded using a UV–visible spectrometer. It was found that the absorption and attenuation coefficients of the PADC (CR-39) exhibit a strong dependence on the wavelength of ultraviolet radiation. The PL spectra were measured with a Flormax-4 spectrofluorometer (Horiba). PADC (CR-39) samples were excited by ultraviolet radiation with wavelengths in the range from 260 to 420 nm and the corresponding PL emission bands were recorded. The obtained results show a strong correlation between the PL and the excitation wavelength of ultraviolet radiation. The position of the fluorescence emission band peak was red shifted starting from 300 nm, which was increased with the increase in the excitation wavelength. The PL yield and its band peak height were increased with the increase in the excitation wavelength till 290 nm, thereafter they decreased exponentially with the increase in the ultraviolet radiation wavelength. These new findings should be considered carefully during the use of the PADC (CR-39) in the scientific applications and in using PADC (CR-39) in eyeglasses. [ABSTRACT FROM AUTHOR]

The correlation between the induced modifications in the photoluminescence spectra and the optical energy band gaps upon exposure to short ultraviolet C (UVC) of 254 nm in the polymers-based solid state nuclear track detector Makrofol®De 1-1 were investigated. Samples of Makrofol®De 1-1 were exposed to UVC radiation of 254 nm for different durations in air, thereafter the UV–visible and photoluminescence spectra were measured. It was found that Makrofol®-De 1-1 shows substantial's modifications in its optical and fluorescence characteristics upon exposure to UVC with a wavelength of 254 nm. UV–visible spectra of UVC irradiated Makrofol®De 1-1 shows continues red shift. Furthermore, a shoulder was observed in the wavelength range from 300 to 330 nm. Both of the red shift and the absorbance at the shoulder increase with the increase in the exposure time which seems to be saturated at prolonged exposure times more than 180 min. Photoluminescence spectra of UVC irradiated Makrofol®De 1-1 show a reasonable modifications upon exposure to UVC with a wavelength of 254 nm. The width at the half height of the band peak and the red shift of the photoluminescence spectra increase with the increase in the exposure time till the exposure time of 180 min, thereafter no significant changes were observed. It is found that the red shift and width of the photoluminescence spectra are correlated with the optical energy band gaps upon UVC irradiation. The peak wavelength as well as the band width of the photoluminescence spectra increases with the decrease in the optical band gaps. This experiment can provide an integrated understanding of utilizing Makrofol®De 1-1 in low linear energy transfer radiation dosimetry by connecting the concepts of photoluminescence, optical band gaps, and carbon clusters. [ABSTRACT FROM AUTHOR]

In the current work, alpha particle spectroscopy is investigated experimentally by utilizing the over-etched track lengths in the CR-39 detector. CR-39 samples were exposed perpendicularly to alpha particles emitted from 241Am with an energy ranging from 0.5 to 5.5 MeV. CR-39 samples were etched in 6.25 N NaOH at (70±0.5)°C for different durations. The track diameter and track length were measured under an optical microscope. The results show that, the energy-over-etched track length calibration curve is monotonic, in other words, the over-etched track length is a monotonic function in alpha particle energy. On the other hand, the energy-diameter calibration curve is degenerated, i.e. alpha track diameter is non-monotonic function in alpha particle energy. These results suggest that the CR-39 detector could be used as a wide range alpha particles spectrometer using an energy-over-etched track length calibration curve. [ABSTRACT FROM PUBLISHER]

The induced modifications of the optical properties in UV-irradiated Makrofol-E with different wavelengths were investigated. Makrofol-E samples were irradiated by UV of wavelengths 254, 302, and 365 nm for different durations. It was found that Makrofol-E shows substantial modifications in its optical characteristics upon exposure to UV of wavelengths 302 and 254 nm, but no modifications were observed at 365 nm. UV-irradiated Makrofol-E with wavelengths 254 and 302 nm exhibits shoulder bands at 297 nm in UV–visible spectra. For an exposure time less than 20 h, the band absorbance strengths depend on the exposure time and approximately increases linearly, but for prolonged exposure times, the band absorbance strengths become almost saturated. The optical energy band gaps obtained from the direct and indirect allowed transition in K-space. Both of them decrease with the increase in exposure time for wavelengths of 254 and 302 nm. Urbach's energy increases with increase in the exposure time for both wavelengths of 254 and 302 nm. The number of carbon atoms in a cluster increases with the increase in the exposure time. [ABSTRACT FROM AUTHOR]

Experiments have been performed to explore the potential of the low emittance 855MeV electron beam of the Mainz Microtron MAMI for imaging with coherent X-rays. Transition radiation from a micro-focused electron beam traversing a foil stack served as X-ray source with good transverse coherence. Refraction contrast radiographs of low absorbing materials, in particular polymer strings with diameters between 30 and 450μm, were taken with a polychromatic transition radiation X-ray source with a spectral distribution in the energy range between 8 and about 40keV. The electron beam spot size had standard deviation σh = (8.6±0.1)μm in the horizontal and σv = (7.5±0.1)μm in the vertical direction. X-ray films were used as detectors. The source-to-detector distance amounted to 11.4m. The objects were placed in a distance of up to 6m from the X-ray film. Holograms of strings were taken with a beam spot size σv = (0.50±0.05)μm in vertical direction, and a monochromatic X-ray beam of 6keV energy. A good longitudinal coherence has been obtained by the (111) reflection of a flat silicon single crystal in Bragg geometry. It has been demonstrated that a direct exposure CCD chip with a pixel size of 13×13μm^2 provides a highly efficient on-line detector. Contrast images can easily be generated with a complete elimination of all parasitic background. The on-line capability allows a minimization of the beam spot size by observing the smallest visible interference fringe spacings or the number of visible fringes. It has been demonstrated that X-ray films are also very useful detectors. The main advantage in comparison with the direct exposure CCD chip is the resolution. For the Structurix D3 (Agfa) X-ray film the standard deviation of the resolution was measured to be σf = (1.2±0.4)μm, which is about a factor of 6 better than for the direct exposure CCD chip. With the small effective X-ray spot size in vertical direction of σv = (1.2±0.3)μm and a geometrical magnification of up to 7.4 high-quality holograms of tiny transparent strings were taken in which the holographic information is contained in up to 18 interference fringes. [ABSTRACT FROM AUTHOR]

Makrofol ® DE 1-1 (bisphenol-A polycarbonate) was characterized as a solid state nuclear track detector (SSNTD) as well as for alpha particle detection. The bulk etch rate of the Makrofol ® DE 1-1, at different etchant concentrations and temperatures, was found to be homogenous. The visible light absorbance measurements of the etched Makrofol ® DE 1-1 at different etching conditions indicated that the lowest visible light absorbance occurs at the etching conditions of 75% 6 N KOH+25% C 2 H 5 OH and a temperature of 50∘C. The bulk etch rate activation energy E B increased from (0.59 ± 0.05) eV to (0.76 ± 0.05) eV for Makrofol ® DE 1-1 etched in KOH and 25% 6 N KOH+75% C 2 H 5 OH, respectively. Before alpha particle tracks overlapping, the alpha track density in Makrofol ® DE 1-1 is linearly correlated with the exposure time to alpha particles. The alpha particles track diameter was found to be a non-monotonic function of the alpha particle energy. The range of alpha particles in Makrofol ® DE 1-1, which is a monotonic function of alpha particle energy, was determined using the over-etched track technique. The range-energy relationship of a perpendicularly incident alpha particle in a Makrofol ® DE 1-1 detector can be used for the determination of the alpha particle energy over a wider energy range than with the etch pit diameter-energy relationship. • Makrofol® DE 1-1 was investigated as SSNTD. • Optimal etching conditions were determined. • Bulk etch rate activation energy were determined. • Alpha particles detection based on Energy-range relationship is presented. [ABSTRACT FROM AUTHOR]

In this present study, a color contrast approach was proposed to find a method for quantify uncertainty in alpha particle spectroscopy using nuclear track detectors (NTDs). According to this method, this color contrast approach was applied to NTDs as an alpha particle spectrometer. A comparison between the registration of 4.0 MeV alpha particles by Makrofol®DE 1-1 and CR-39 NTDs using a color contrast method was carried out in alpha spectroscopy. The contrast of the alpha tracks of each single color channel whether red, green and blue resulting from split RGB image was determined. The measurements were proved that green color channel produced the highest contrast of the alpha tracks of about 85%, in both Makrofol® DE 1-1 and CR-39 NTDs. The results of 4.0 MeV alpha particle etch-pits diameters in Makrofol® DE 1-1 didn't show homogenous diameters for short etching time. The standard deviation of 4.0 MeV alpha-track diameters in Makrofol® DE 1-1 went up to a maximum value of 2.23 μm at a removal thickness of 12.25 μm. When increasing the etching time, they decreased sharply to about 1.18 ± 0.02 μm at a ratio of change 0.047 that was less than 6%. The standard deviation of 4.0 MeV alpha particle etch-pit diameters in CR-39 detector was linearly correlated with the removal thickness at a ratio of change of 0.02 which was less than 5%. Results revealed that the etch-pit diameter in Makrofol® DE 1-1 detector, in alpha particle spectrometry was best measured around the end of the alpha particle range. Results of this study are discussed within the frame work of nuclear track formation theories and etching mechanism in nuclear track detectors (NTDs). • The contrast and visualization of the etch-pit alpha tracks are enhanced when they are scanned by monochromatic light.. • Standard deviations (σ) of alpha-track diameters in NTDs involved in alpha spectroscopy are reported.. • Makrofol can be used in alpha spectroscopy with 6% track size resolution if the tracks are measured at the range's end.. [ABSTRACT FROM AUTHOR]

• XRD diffraction and Mössbauer spectroscopy were used to examine how adding different heavy metals affected the structure of the prepared glasses. • The prepared glasses (50 %P 2 O 5 + 20 %Na 2 O + 20 %Fe 2 O 3 + 10 % X, where. • X = As 2 O 3 , SrO, BaO, CdO, and Sb 2 O 3) ability to block gamma rays was investigated. • Results indicated that glass sample containing Sb 2 O 3 is the best-modified glass for gamma radiation protection. Mössbauer spectroscopy analysis and gamma (γ)-ray shielding performance for some iron phosphate glasses with composition 50 %P 2 O 5 + 20 %Na 2 O + 20 %Fe 2 O 3 + 10 % X , where X = As 2 O 3 , SrO, BaO, CdO, and Sb 2 O 3 w.t.% were investigated. The melt quenching technique was used for glass sample preparation, where the X R D patterns investigated the amorphous nature of the prepared glasses. Moreover, SEM and EDS mapping were used to provide information on the element distribution of the added heavy metals. Mössbauer spectroscopy showed that, most of the iron is present in the glass as Fe3+oxidation state, which is composed of tetrahedral and octahedral coordination states. The remaining iron ions have the form Fe2+ which occupied the tetrahedral coordination state. The γ -ray attenuation parameters like, mass attenuation coefficient (M A C), half value layer (H V L) and the effective atomic number (Z e f f) were experimentally measured at different γ -ray energies using 133Ba, 137Cs, and 60Co radioactive sources. Results indicated that the sample containing Sb 2 O 3 is the best-modified glass for gamma radiation protection. [ABSTRACT FROM AUTHOR]

The objectives of the current work are to investigate the modification of the self-developed GafChromic EBT2 radiochromic film, to register 2 MeV alpha particles, by eliminating the polystyrene layer of 50 μm and the adhesive layer of 15 μm. Such modification enables 2 MeV alpha particles to reach and interact directly by the diacetylene monomers active layer of thickness 30 μm. The modified EBT2 radiochromic film, EBT2-M was irradiated by alpha-particles of 2 MeV starting from 1 h to 300 h in a clean dark room; one day later the irradiated EBT2 films were scanned with a flatbed scanner, and the absorbance spectra were measured by UV-VIS spectrophotometer. The obtained results reveal that the darkness of the irradiated EBT2-M film increases with the increasing of the exposure time to 2 MeV alpha particles, but for a prolonged exposure time the darkness is saturated. The UV-VIS absorbance spectra at 502 nm, 525 nm, 582 nm, 602 nm, and 631 nm are correlated with exposure time to 2 MeV alpha particles, which is, in turn, the absorbed dose by an exponential growth function that saturates at a prolonged exposure time, when diacetylene monomers are completely polymerized. The color channel level Red, Green, and Blue resulting from split RGB image was determined and investigated as a function in the exposure time to the alpha particle of 2 MeV, the color scale level decreases exponentially with the increase in exposure time. The reported results of the grey, red and green color scale have similar absorbance whereas the blue color channel shows insignificant behavior. The presented results pave the way to use the modified EBT2-M radiochromic film to mapping the relative dose delivered by low-energy alpha particles. • First registration of the low-energy alpha particle with modified GafChromic EBT2. • The Canon CanoScan flatbed scanner is used to readout the GafChromic EBT2-M films. • Absorbance spectra of GafChromic EBT2 films are measured with UV-VIS spectroscopy. • The color channel red, green and blue investigated as a function of exposure time. [ABSTRACT FROM AUTHOR]

The present work aimed to study the γ-ray irradiation effects on the physical and chemical behavior of poly methyl methacrylate (PMMA) thin polymeric sheets doped with different concentrations of nano CdO (0.3–1.8 wt. %). Co-precipitation technique was used to prepare CdO nanopowder, while casting-solution method was applied to prepare thin sheets of PMMA/CdO. The XRD analysis of CdO, PMMA and their composites confirmed their formation in pure phase. The particle size distribution of the CdO powder was estimated using TEM imaging and found to be 3–20 nm. According to optical microscopy investigation, good homogeneous distribution was obtained for the CdO powder inside the PMMA sheets. Different sets of the prepared samples were irradiated by γ-ray of 60Co source with gradually increasing doses (20–120 kGy). The irradiated samples were analyzed using XRD, FTIR and UV/Vis spectroscopy. Comparative study was done on pristine and irradiated samples at different CdO concentration. The visual appearance of the samples showed chromatic degradation with increasing both CdO concentration and absorbed γ-ray doses. A color map of the irradiated PMMA/CdO samples was presented for monitoring the absorbed dose. The changes in the samples color was attributed to conversion of CdO (reddish brown) to Cd(OH) 2 (clear white) as a result of γ-ray irradiation. The unirradiated samples showed slight decrease in their optical band gap with increasing CdO concentration. Furthermore, a linear correlation between the optical band gap and γ-ray dose was deduced for all the irradiated samples. Electrical permittivity and conductivity of pristine and irradiated samples were measured as a function of frequency at room temperature using LCR bridge. A relative increase in the dielectric constant and AC conductivity of the irradiated samples by about 5–25% was observed for the highest CdO concentration. The electrical parameters of the irradiated samples showed significant changes at high γ-ray dose of 120 kGy. The obtained experimental data were discussed in view of γ-ray interaction with the medium using the suitable models and theories of polarization mechanisms. The results are promising for using the prepared samples as γ-ray dosimeters in addition to enhancement of their electrical properties for various applications. • CdO/PMMA sheets have linear chromatic degradation by γ-ray irradiation. • Optical parameters of the CdO/PMMA are correlated with absorbed dose. • γ-ray irradiation affects dielectric and conductivity parameters of polymeric matrix. [ABSTRACT FROM AUTHOR]

In this study two methods, solid-state (S–S) and sol-gel (S-G), were used to prepare ZnO/NiFe 2 O 4 (assigned as ZnO/NF) hetero nanocomposites with different NF contents (0, 5, 10, 15, 20 and 25 wt %). The prepared composites were investigated using XRD, EDX, HR-TEM to study their structural and morphological properties. The obtained XRD patterns have been analyzed by employing the Rietveld refinement technique. The results confirmed the formation of ZnO/NF composites with individual characteristic peaks corresponding to both ZnO and NF, and no impurities were detected. HR-TEM images showed nearly spherical particles for all samples with an average particle size of 23–72 nm. The magnetic parameters were estimated from the measured hysteresis loops using a vibrating sample magnetometer (VSM). The samples showed typical ferromagnetic behavior with different saturation magnetization (M s) and coercivity (H c) depending on the NF contents and the preparation route. The values of initial permeability (μ i) showed independent behavior on the frequency and its correlation with saturation magnetization M s and particle size was discussed. The study may help in enhancing the magnetic properties of ZnO by doping with NF. The comparison between two preparation techniques may provide optimum conditions to be used in development of multiphase materials for various applications. • Nanocomposites ZnO/NF were prepare by two methods. • The ferromagnetic behavior was dominant in all samples. [ABSTRACT FROM AUTHOR]

Absolute cross-sections for the K-shell photoionization of Be-like (O4 +) and Li-like (O5 +) atomic oxygen ions were measured for the first time (in their respective K-shell regions) by employing the ion--photon merged-beam technique at the SOLEIL synchrotron-radiation facility in Saint-Aubin, France. High-resolution spectroscopy with E/ΔE ≈ 3200 (≈170 meV, full width at half-maximum) was achieved with photon energy from 550 to 670 eV. Rich resonance structure observed in the experimental spectra is analysed using the R-matrix with pseudo-states (RMPS) method. Results are also compared with the screening constant by unit nuclear charge (SCUNC) calculations. We characterize and identify the strong 1s → 2p resonances for both ions and the weaker 1s → np resonances (n ≥ 3) observed in the K-shell spectra of O4 +. [ABSTRACT FROM AUTHOR]

Abstract: Experiments were performed with the 855MeV electron beam of the Mainz Microtron MAMI which focused on still open questions in the X-ray emission process upon traversal of ultra relativistic electrons through single crystals. To elucidate the quest of kinematical versus dynamical production of PXR the radiation from silicon single crystal targets, emitted close to the electron direction, has been studied. The observed interference structures show that PXR is produced in a dynamical process. [Copyright &y& Elsevier]