Photon Energy Range Research Articles

UV-VUV absorption spectra of azido-based energetic plasticizer bis(1,3-diazido prop-2-yl)malonate in gas phase.

Ultraviolet and vacuum ultraviolet photo-absorption spectra of azido (-N3)-based energetic plasticizer, bis(1,3-diazido-prop-2-yl)-malonate (abbreviated as BDAzPM), in the gas phase is recorded at room temperature and in the photon energy range of 5.5-9.9eV using a synchrotron radiation source. Complementary computational results obtained using the time-dependent density functional theory document the vertical transition energies and oscillator strengths. Comparison of the simulated spectra with the experimental absorption spectrum of BDAzPM reveals that the early part of the absorption spectrum of BDAzPM is of pure valence excitation character, whereas the later intense part of the absorption spectrum is dominated by mixed Rydberg and valence electronic excitations.

Physical properties of newly synthesized noncentrosymmetric TaIr2B2 and NbIr2B2 superconductors: an extensive comparison of GGA and LDA functional investigations.

In recent years, noncentrosymmetric (NCS) structural compounds have received much attention from the scientific community in the exploration for the unconventional nature of superconductivity with exciting physical properties. This study uses the comprehensive generalized gradient approximation (GGA) and local density approximation (LDA) to gain insights into the physical properties of two recently synthesized Ir-based NCS superconductors, TaIr2B2 and NbIr2B2. The structural parameters, mechanical performance, electronic structure, Debye temperature, melting temperature, electronic specific heat, and electron-phonon coupling constant of TaIr2B2 and NbIr2B2 are explored and discussed in detail. Density functional theory (DFT) optimized structural parameters of both NCS phases agree well with experimental observation. Both GGA and LDA calculations show that the compounds are ductile, machinable, mechanically stable, and anisotropic in nature. The elastic moduli and hardness calculations reveal that TaIr2B2 is harder than NbIr2B2. The calculation of the melting temperature reveals that TaIr2B2 is more suitable for high temperature technology applications compared to NbIr2B2. Both GGA and LDA functionals reveal that the optical functions are very similar. Both compounds display a significant amount of reflectivity spectra over a wide range of photon energies. The GGA functional reveals a somewhat higher density of states value compared to that of LDA. The present calculated values of the electron-phonon coupling constant of both compounds are consistent with values previously reported from experimental studies.

Study of population dynamics toward the development of atomic X-ray lasers in the 3–5 keV photon energies

X-ray free-electron lasers (XFELs) are powerful tools for characterizing and probing the properties of matter at atomic resolution on the ultrafast timescale. However, they have certain limitations such as spectral fluctuation and poor temporal coherence. Atomic X-ray lasers offer the narrow bandwidth, longitudinal coherence, and spectral stability that can overcome these limitations. In this paper, we study the interaction of inner-shell vacancy states with high-intensity XFEL pulses. We show that it is possible to achieve population inversion between K-shell and L-shell vacancy states in calcium and titanium when pumped by high-intensity XFEL pulses. These states can be used to generate atomic X-ray laser emission in the 3–5 keV photon energy range.

Dissociative photoionization of acetaldehyde in the 10.2-19.5 eV VUV range.

The valence-shell dissociative photoionization of acetaldehyde has been investigated by means of the photoion photoelectron coincidence technique in conjunction with tuneable synchrotron radiation. The experimental results consist of threshold photoelectron spectra for the parent ion and for each fragment ion in the 10.2-19.5 eV photon energy range, along with (ion, e) kinetic energy coincidence diagrams obtained from measurements at fixed photon energies. The results are complemented by high-level ab initio calculations of potential energy curves as a function of the C-H bond distance. The nudged elastic band (NEB) method has been employed to connect the parent ion Franck-Condon region to the formation of the HCO+, CH3+ and CH4+ ion fragments. Appearance energies have been determined for six fragment ions with an improved accuracy, including two fragmentation channels, which to the best of our knowledge have not been reported previously, i.e. the formation of CH2CO+, lying at 13.10 ± 0.05 eV, and the formation of CH2+ at 15.1 ± 0.1 eV. Based on both experimental and theoretical results, the dissociation dynamics following ionization of acetaldehyde into the different fragmentation channels are discussed.

Investigation of the Suitability of Different Materials as Human Tissue Simulating Materials in Co-60 Radiation Energy Beam

Radiotherapy calibration for precise dose delivery traditionally relies on water phantom systems, but this approach poses challenges of heterogeneous corrections or the use of anthropomorphic phantoms which most underdeveloped nations find expensive. In this study, the suitability of some tissue simulating materials were investigated within the Co-60 photons energy range. This study explores the identification of locally sourced materials to simulate human tissue behavior in Co-60 energy beams. By considering effective atomic numbers and physical densities, we evaluate materials for simulating soft tissue, lung, and bone. Water, aluminum metal, and polystyrene (Styrofoam) were selected for simulating soft tissue, bone, and lung, respectively, due to their close radiological properties, availability, and affordability. This research provides valuable insights for resource-constrained regions aiming to improve radiotherapy calibration methods.

Optical control of degradation of polytetrafluoroethylene films and its modification under electron irradiation

A method for monitoring the degradation of the optical density in polytetrafluoroethylene films and its modification, a copolymer of tetrafluoroethylene and ethylene, irradiated by electrons with energies of 100 keV and 10 MeV is described. The method is based on measuring the optical density of irradiated films in the photon energy range of 1-6 eV and is confirmed by established «dose-optical absorption» relationships. In particular, using the described method, a completely different nature of the radiation degradation of the optical properties of the two types of films under study was discovered. With an increase in the irradiation dose, «bleaching effect» in the region of 2-5 eV and the appearance of an absorption band at 5.6 eV are observed in polytetrafluoroethylene films. With a similar dose increase, three absorption bands at 4.0, 4.6 and 5.5 eV appear and grow in films of copolymer of tetrafluoroethylene and ethylene. The evidence of the critical role of the optical density of films in the functioning of space technology devices is given.

Design strategies and technology of Elettra 2.0 for a versatile offer to the user community

Elettra 2.0 will be a fourth generation storage ring light source replacing the existing Elettra synchrotron. This article illustrates design strategies, physical investigations and technical choices to meet multiple and sometimes conflicting requirements. These include to make Elettra 2.0 a fully transversely coherent source up to 0.5 keV-photon energy, diversify the type of experiments through a very broad range of photon energies, from infrared to hard x-rays, maximize the number of photon beamlines in excess of 2-times the machine periodicity, and be able to produce picosecond-long light pulses at MHz repetition rate without interference to the standard multi-bunch operation. Most recent advancements in beam physics, technical systems and installation plan are reported with some detail.

Optimal design and characteristic analysis of CsPbBr3 nanocrystals hybridized with 2,5-diphenyloxazole molecules for UV and X-ray detection

Scintillation is a flash of light produced in a material by the passage of a high-energy particle or photon. Desirable properties of scintillators, such as high quantum yield, low afterglow, and radiation hardness, are determined by their physical and optoelectronic properties. Metal halide perovskite (CsPbX3, X = Cl, Br, I) nanocrystals (NCs) have gained increasing attention as materials for optical and X-ray scintillators across a wide range of incident photon energies owing to their outstanding luminescent properties. In this study, we demonstrate the dependence of scintillation yield (SY) on incident photon energy ranging from ultraviolet (UV) light to X-rays in colloidal CsPbBr3 NCs hybridized with organic molecules (2,5-diphenyloxazole: PPO). The measured SY varied with the changing concentration ratio of NCs and PPO molecules. Experimental and theoretical analyses suggested that the SY is associated with the competition between photoluminescence quenching (reabsorption) and photoelectric effect enhanced by X-ray photon induced charge transfer from the organic molecules to the NCs. The optimally engineered hybrid nanomaterial scintillator exhibits excellent X-ray imaging with sharp image contrast (i.e., super-resolved edge spread function (ESF)), under X-ray irradiation commonly used for diagnosis.

Radiation Shielding efficiency of lead-tungsten-boron glasses with Sb, Al, and Bi against gamma, neutron and charge particles

We report on newly developed nuclear shielding glass system based on lead-tungsten-boron (PWB) for radiation applications against photon, neutron and charge particles. This newly developed system contains also different additions, in low concentrations, such as Sb, Al and Bi. The gamma/photon shielding performance was tested by using FLUKA Monte Carlo. Moreover, the shielding efficiency of the present system is examined against charged particles (light and heavy ones) and neutrons. The highest gamma/photons attenuation is observed in the lowest incident energy and this is at the region of the photoelectric absorption. We also observe that the values of effective atomic number (Zeff) show a peak at 100 keV incident energy. The reduction of these values is higher for photon energy range 0.1–1 MeV than below 80 keV energies. The lowest half value layer (d1/2), reflecting the best shielding efficiency, is recorded for the PWB-Bi system. The PWB-Bi system demonstrates promising performance better than many of commercial and standard systems and heavy concretes.

Unveiling the electronic, optical, thermoelectric, and thermodynamic properties of novel SrXCu3Se4 (X = In, Tl) materials: A systematic DFT study

Direct band gaps in semiconductors are extremely valuable for numerous optoelectronic devices, particularly for solar cells. This work investigated the novel quaternary chalcogenide SrXCu3Se4 (X = In, Tl) for its electronic, optical, thermoelectric, and thermodynamic characteristics. The present study made use of state-of-the-art density functional theory. From the electronic band profiles showed that both materials display a direct band gap semiconductor nature, provided more evidence for the reliability of our conclusions on the density of states plot. Additionally, we investigated and provided a thorough study of the significant optical responses in the photon energy range of 0 to 14 eV. We also investigated the thermodynamic properties of these quaternary systems using the quasi-harmonic Debye model. We evaluated and discussed about the most important thermoelectric transport variables for future thermoelectric applications. Finally, we examined the significant thermodynamic parameters that varied in pressure and temperature ranges from 0 to 20 GPa and 0 to 1000 K, respectively.

Experimental Study on The Gamma Ray Absorption Properties of Lanthanum and Cerium Borides

The objective of this study is to investigate the mass attenuation coefficients (μm) of lanthanumhexaborides and ceriumhexaborides over a wide photon energy range emitted from the main radioactive sources used in medicine and industry. 125I, 99mTc, 131I, 137Cs, 60Co and 152Eu gamma ray sources were used in the experiments. The materials synthesized in powder form were first pelletized and then irradiated by photon beams. At the end, it was seen that there is successful consistency between the obtained experimental data and the previous theoretical results. It was also observed that the investigated samples are comparable enough to the known standard gamma shielding materials, especially to lead which is one of the most common one. In conclusion, it is understood that the presently investigated samples have a promising aspect in terms of developing new shielding materials against gamma rays.

A new nanocomposite of copper oxide and magnetite intercalated into Attapulgite clay to enhance the radiation shielding

The effects of Magnetite (Fe3O4) on the radiation shielding properties of different nanocomposites from Attapulgite (ATP) intercalated with different copper oxide (CuO) and magnetite nano (Fe3O4) concentrations were investigated. Different nanocomposites from ATP intercalated with different copper oxide CuO and magnetite nano Fe3O4 concentrations have been synthesized and implemented toward radiation attenuation. The different percent were as the following 40% ATP + X Fe3O4 + (60%–X) CuO that abbreviated to [AT40FeXCu60-x] where X = 15.0%, 30.0%, 45.0%. The ATP and one of the prepared nanocomposites have been characterized using different techniques: FT-IR, TGA, XRD, EDX, and SEM. The density of the synthesized materials was determined. Then their radiation shielding properties were established using GEANT4 and Phy-X software in the selected range of photon energies of 0.015 – 15 MeV. The linear attenuation coefficient (μ), the mass attenuation coefficient (μm), the mean free path (MFP), the half value layer (T1/2), the tenth value layer (T1/10), the effective atomic number (Zeff), and the equivalent atomic number (Zeq) have been calculated to find out the radiation shielding characteristics of the new novel nanocomposites. The μm values were varied from 4.5894 to 0.0204 cm2 g-1 for Base, from 11.9780 to 0.02172 cm2 g-1 for AT40Fe15Cu45, from 12.5030 to 0.02190 cm2 g-1 for AT40Fe45Cu15 and finally from 12.2480 to 0.02181 cm2 g-1 for AT40Fe30Cu30 at photon energy range from 0.015 to 15 MeV. The results showed that the values of the radiation shielding parameters increased with increasing nano Fe3O4 concentration, and the AT40Fe45Cu15 sample has the highest μm and μ and lowest T1/2, T1/10 and MFP. The results of this study have important implications for the development of new radiation-shielding materials. ATP-doped Fe3O4-CuO glasses are a promising new class of radiation shielding materials with improved properties. In conclusion, the study found that the nanocomposite materials with higher nano Fe3O4 concentration have better shielding qualities against γ-rays and neutrons. The AT40Fe45Cu15 sample has the highest shielding qualities for γ-rays, while the AT40Fe30Cu30 sample has the highest fast neutron removal cross-section.

Developing of Lead/Polyurethane Micro/Nano Composite for Nuclear Shielding Novel Supplies: γ-Spectroscopy and FLUKA Simulation Techniques.

In this work, the effect of adding Pb nano/microparticles in polyurethane foams to improve thermo-physical and mechanical properties were investigated. Moreover, an attempt has been made to modify the micron-sized lead metal powder into nanostructured Pb powder using a high-energy ball mill. Two types of fillers were used, the first is Pb in micro scale and the second is Pb in nano scale. A lead/polyurethane nanocomposite is made using the in-situ polymerization process. The different characterization techniques describe the state of the dispersion of fillers in foam. The effects of these additions in the foam were evaluated, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray diffraction (XRD) have all been used to analyze the morphology and dispersion of lead in polyurethane. The findings demonstrate that lead is uniformly distributed throughout the polyurethane matrix. The compression test demonstrates that the inclusion of lead weakens the compression strength of the nanocomposites in comparison to that of pure polyurethane. The TGA study shows that the enhanced thermal stability is a result of the inclusion of fillers, especially nanofillers. The shielding efficiency has been studied, MAC, LAC, HVL, MFP and Zeff were determined either experimentally or by Monte Carlo calculations. The nuclear radiation shielding properties were simulated by the FLUKA code for the photon energy range of 0.0001-100 MeV.

Electronic, optical and thermoelectric properties of Cs2XInCl6 (X = Ag, Na) halide double perovskites

Herein, the optoelectronic, structural, thermoelectric and elastic features of halide double perovskites (HDPs) Cs2XInCl6(X=Ag, Na) are examined by using full‐potential linearized augmented plane wave (FP‐LAPW) technique. The Generalized Gradient Approximation (GGA) and Tran‐Blaha modified Becke‐Johnson (TB‐mBJ) potential is employed to figure out the features of mentioned compounds. The computed values of direct band‐gaps (Eg) for Cs2AgInCl6 and Cs2NaInCl6 compounds are 2.52 and 5.24 eV, correspondingly. The stability of perovskites is confirmed in terms of formation energy ΔHf, tolerance factor (τ) and octahedral factor. Furthermore, optical properties analysis demonstrates that studied compound exhibit conductivity and absorptivity across a broad range of incident photon energy with minimum R(ω). Moreover, outcomes of elastic parameters display isotropic and ductile nature for both materials. Thermoelectric (TE) properties like thermal conductivity (k/τ), power factor (PF), electrical conductivity (σ/τ) and Seebeck coefficient (S) are also calculated by utilizing BoltzTrap code. Cs2NaInCl6 attained the maximum value of ZT (0.76) with PF of 0.42. Computed TE and optical parameters indicate that Cs2XInCl6(X=Ag, Na) are promising for usages in solar absorbing and energy conversion devices.This article is protected by copyright. All rights reserved.

A versatile wide energy range spectrometer for soft X-ray FELs

The design and main characteristics of the Wide Energy range Spectrometer at TIMEX (WEST) operating at the FERMI Free Electron Laser are described. WEST covers the entire photon energy range of the FERMI source including its fundamental emission (extreme ultraviolet region, EUV) and its highest harmonics (soft X-ray region) spanning about a thousand of electrovolts from 20 to 1000 eV. The instrument is specifically designed to measure FERMI FEL spectra with good resolving power (500<RP<7000) and provide remarkable signal to noise ratio adequate for single-shot experiments. Notably, WEST is aligned in transmission geometry downstream of the TIMEX experimental beamline thus offering a valid diagnostic tool for the characterization of both linear and nonlinear spectral effects driven by the interaction between FEL radiation and samples in gaseous, liquid and solid phase. Detailed theoretical analysis of the instrument performance complemented by experimental measurements is presented. Further possible upgrades of WEST are finally considered and discussed.

A dedicated application of evolutionary algorithms: synchrotron X-ray radiation optimization based on an in-vacuum undulator

Following the rapid growth in accelerator-based light sources research since the mid of 20th century, miscellaneous third generation synchrotron radiation (SR) facilities such as SSRL, APS, ESRF, PETRA-III, and SPring-8 have come into existence. These SR source facilities provide 1020–1025 photons/s/mrad2/mm2/0.1%BW peak brightness within the photon energy range of 10–105 eV. Since different measurement techniques are utilized at X-ray beamlines of SR facilities, many kinds of insertion devices (i.e., undulators and wigglers) and optical components (e.g., high-resolution monochromators, double-crystal monochromators, lenses, mirrors, etc.) are employed for each experimental setup as a matter of course. Under the circumstances, optimization of a synchrotron beamline is a big concern for many scientists to ensure required radiation characteristics (i.e., photon flux, spot size, photon energy, etc.) for dedicated user experiments. In this respect, an in-vacuum hybrid undulator driven by a 6 GeV synchrotron electron beam is optimized using evolutionary algorithms (EA). Finally, it is shown that EA results are well consistent with both the literature and the analytical calculations, resulting in a promising design estimation for beamline scientists.

Cascaded hard X-ray self-seeded free-electron laser at megahertz repetition rate

AbstractHigh-resolution X-ray spectroscopy in the sub-nanosecond to femtosecond time range requires ultrashort X-ray pulses and a spectral X-ray flux considerably larger than that presently available. X-ray free-electron laser (XFEL) radiation from hard X-ray self-seeding (HXRSS) setups has been demonstrated in the past and offers the necessary peak flux properties. So far, these systems could not provide high repetition rates enabling a high average flux. We report the results for a cascaded HXRSS system installed at the European XFEL, currently the only operating high-repetition-rate hard X-ray XFEL facility worldwide. A high repetition rate, combined with HXRSS, allows the generation of millijoule-level pulses in the photon energy range of 6–14 keV with a bandwidth of around 1 eV (corresponding to about 1 mJ eV–1 peak spectral density) at the rate of ten trains per second, each train including hundreds of pulses arriving at a megahertz repetition rate. At 2.25 MHz repetition rate and photon energies in the 6–7 keV range, we observed and characterized the heat-load effects on the HXRSS crystals, substantially altering the spectra of subsequent X-ray pulses. We demonstrated that our cascaded self-seeding scheme reduces this detrimental effect to below the detection level. This opens up exciting new possibilities in a wide range of scientific fields employing ultrafast X-ray spectroscopy, scattering and imaging techniques.

Effects of a 4.3T superconducting wiggler on the electron beam optics and dynamics at NSLS-II

A superconducting wiggler (SCW) with a peak field of 4.3 T has recently been installed at NSLS-II. The wiggler generates a high-flux X-ray beam with a photon energy range from 20 keV to 200 keV for the High Energy Engineering X-ray Scattering beamline. This device induces significant distortions in the electron beam orbit and optics. We have corrected these adverse effects using feed-forward tables. The effects of the SCW on the electron beam emittance, energy spread, and bunch length were calculated and measured. The beam-induced heating of the cryogenic vacuum chamber was also studied. Finally, the superconducting wiggler has been commissioned for user operations.

Insight into What Is inside Swift Heavy Ion Latent Tracks in PET Film.

We present here a novel experimental study of changes after contact electrification in the optical transmission spectra of samples of both pristine and irradiated PET film treated with Kr+15 ions of energy of 1.75 MeV and a fluence of 3 × 1010 cm2. We used a non-standard electrification scheme for injecting electrons into the film by applying negative electrodes to both its surfaces and using the positively charged inner regions of the film itself as the positive electrode. Electrification led to a decrease in the intensity of the internal electric fields for both samples and a hypsochromic (blue) shift in their spectra. For the irradiated PET sample, electrification resulted in a Gaussian modulation of its optical properties in the photon energy range 2.3-3.6 eV. We associate this Gaussian modulation with the partial decay of non-covalent extended conjugated systems that were formed under the influence of the residual radial electric field of the SHI latent tracks. Our studies lead us to suggest the latent track in the PET film can be considered as a variband material in the radial direction. Consideration of our results along with other published experimental results leads us to conclude that these can all be consistently understood by taking into account both the swift and slow electrons produced by SHI irradiation, and that it appears that the core of a latent track is negatively charged, and the periphery is positively charged.

Experimental and Monte Carlo study of energy response of BEO-based OSL detectors within photon energy range up to 15 MeV.

Response of personal dosemeters to high energy photon radiation is of great interest nowadays due to a spread of new radiation technologies and the expansion of occupational exposure domains. ICRU95 publication has expanded the range of relevant photon energies upwards, setting new horizons for individual monitoring. Beryllium oxide (BeO) material is increasingly popular due to its excellent optically stimulated luminescence (OSL) properties, simple readout and reasonable energy response in the low energy (below 100keV) range. The study considers energy dependence of OSL response at higher photon energies. Energy deposition of monoenergetic photons with energy up to 15MeV in the BeO chips of various thickness was modeled with Monte Carlo MCNP 6.2 code. Benchmark experiments were conducted at LINAC with high voltage of 6, 10 and 15 MV resulting in respective incident photon spectra. The findings of this study add knowledge regarding behavior of BeO personal dosemeters in the photon fields within the energy range above 3MeV.