Atomic Number Density Research Articles

Comprehensive study on structural, elastic and radiation shielding abilities of novel quaternary Bi2O3–TeO2–Li2O–Al2O3 glasses

Novel quaternary glasses with varying compositions of xBi2O3-(75–x)TeO2–20Li2O–5Al2O3 were synthesized using a melt-quenching method to analyze their physical, elastic properties and to evaluate their potential as radiation shielding materials. The X-Ray Diffraction (XRD), Fourier Transform Infrared (FTIR) and ultrasonic measurement were utilized to study those properties. The radiation shielding properties of the glass samples were determined for 0.01–10000 MeV photon energy range by using Phy-X/PSD software. The incorporation of Bi2O3, ranging from 0 mol% to 5 mol%, led to an increase in density which is measured by Archimedes' principle, ascending from 4.68 to 5.06 g/cm3. The longitudinal, bulk, shear, and Young's modulus, displayed a non-linear decline from 63.41 to 61.44 GPa, 33.52 to 33.20 GPa, 22.41 to 21.18 GPa, and 54.99 to 52.39 GPa. Furthermore, the inclusion of Bi2O3 up to x = 5 mol% produce mass attenuation coefficient (MAC) of 14.892 cm2/g at x-ray energy of 40 KeV, surpassing that of commercial RS360 and RS520 radiation shielding glasses by 577% and 323%, respectively. When subjected to gamma ray of 662 KeV the MAC is 0.08 cm2/g which was also accompanied by a reduction in the half-value layer (HVL) to 1.58 cm where it surpassed the concrete by 38% and linear attenuation coefficient (LAC) of 0.38 cm−1. The effective atomic number (Zeff) and effective electron density (Neff) reach maximum value of 59.74 and 7.88 × 1023 electrons/g at 0.02 MeV respectively. These results highlight the suitability of the glass composition with x = 5 mol% as an exceptional choice for employment as to shield against both X-rays and gamma rays.

Gamma-ray shielding effectiveness, thermal, and dielectric properties of filler-reinforced high-density polyethylene/boron carbide composites

The present research prepared samples of pure high-density polyethylene (HDPE)/boron carbide reinforced with iron dioxide, aluminum dioxide, iron, and aluminum. The effectiveness of the prepared samples as a shielding material against gamma-rays and their thermal and dielectric properties have been evaluated. The shielding characteristics of the prepared composites were investigated theoretically using the Phy-X/PSD program and experimentally for gamma-rays emitted from 131Cs and 60Co radioactive isotopes. The shielding evaluation included the mass attenuation coefficient (μ/ρ), half value layer (HVL), mean free path (MFP), atomic and electronic cross-sections (σa&σe), effective atomic number and electron density (Zeff &Neff), and exposure build-up factor (EBF). The EBF peaks of samples containing Fe and Fe2O3 are 103 times lower than pure HDPE. The results indicate that samples C2 and C3 have a higher ability to protect against gamma radiation than that of the other investigated samples. X-ray diffractometer (XRD) spectrum shows that adding B4C, Fe, Fe2O3, Al, and Al2O3 to HDPE caused an increase in its full width at half maximum (FWHM) value and a decrease in its average crystallite diameters (D) at its primary characteristic scattering angle of 21.49°. Adding multiple types of fillers to HDPE results in a minor shift in the melting temperature of the hosting matrix as proved from differential scanning calorimetry (DSC) data. The composite of HDPE/B4C/Al2O3 60/10/30 demonstrated the most significant values of dielectric parameters in comparison with the other composites, in good accord with the XRD results. The ac conductivity relied on the dopant type in the hosting matrix; the highest value was observed for HDPE/B4C/Al2O3 composite.

Material decomposition with a prototype photon-counting detector CT system: expanding a stoichiometric dual-energy CT method via energy bin optimization and K-edge imaging

Objective. Computed tomography (CT) has advanced since its inception, with breakthroughs such as dual-energy CT (DECT), which extracts additional information by acquiring two sets of data at different energies. As high-flux photon-counting detectors (PCDs) become available, PCD-CT is also becoming a reality. PCD-CT can acquire multi-energy data sets in a single scan by spectrally binning the incident x-ray beam. With this, K-edge imaging becomes possible, allowing high atomic number (high-Z) contrast materials to be distinguished and quantified. In this study, we demonstrated that DECT methods can be converted to PCD-CT systems by extending the method of Bourque et al (2014). We optimized the energy bins of the PCD for this purpose and expanded the capabilities by employing K-edge subtraction imaging to separate a high-atomic number contrast material. Approach. The method decomposes materials into their effective atomic number (Z eff) and electron density relative to water (ρ e ). The model was calibrated and evaluated using tissue-equivalent materials from the RMI Gammex electron density phantom with known ρ e values and elemental compositions. Theoretical Z eff values were found for the appropriate energy ranges using the elemental composition of the materials. Z eff varied slightly with energy but was considered a systematic error. An ex vivo bovine tissue sample was decomposed to evaluate the model further and was injected with gold chloride to demonstrate the separation of a K-edge contrast agent. Main results. The mean root mean squared percent errors on the extracted Z eff and ρ e for PCD-CT were 0.76% and 0.72%, respectively and 1.77% and 1.98% for DECT. The tissue types in the ex vivo bovine tissue sample were also correctly identified after decomposition. Additionally, gold chloride was separated from the ex vivo tissue sample with K-edge imaging. Significance. PCD-CT offers the ability to employ DECT material decomposition methods, along with providing additional capabilities such as K-edge imaging.

Enhancing Dynamic Performance in K-Rb-21Ne Co-Magnetometers through Atomic Density Optimization

The K-Rb-21Ne co-magnetometer exhibits poorer dynamic performance due to the larger equivalent magnetic field generated by alkali metal atoms. In this study, the impact of the atomic number density of alkali metal atoms and noble gas atoms in the cell on the dynamic performance of the atomic ensemble is investigated quantitatively. Relationships between the slow-decay term in the transient response attenuation of the Spin-Exchange Relaxation-Free (SERF) co-magnetometer to interference magnetic fields and the number densities of noble gas atoms as well as alkali metal atoms are established. Based on the established model, the relationship between the number density of 21Ne atoms and dynamic performance is investigated using cells with five different noble gas pressures. Then, we investigate the impact of the number density of alkali metal atoms using a cell with a pressure of 2.1 atm at different temperatures. The results indicate that, as the number density of alkali metal atoms or noble gas atoms in the cell increases, the dynamic performance of the system improves, which provides a theoretical basis for the design of cell parameters for SERF co-magnetometers.

Gradual weakening down to complete disappearance of the velocity correlated cluster emission effect in keV collisions of C60 with light metallic targets: Microscopic insights via molecular dynamics simulations

The so-called velocity correlated cluster emission (VCCE) effect is the recently reported emission of large clusters with nearly the same velocity from an atomically heavy target (such as coinage metals) following a single C60− impact at the keV kinetic energy range. The effect was observed to get weaker for a meaningfully lighter target (Al) down to its complete disappearance for C60–Be impact. Microscopic insight into the subpicosecond evolution and thermalization of the impact induced energy spike (driving the effect) is achieved using molecular dynamics simulations. It is shown that the weakening of the VCCE effect for aluminum (toward its complete disappearance for Be) is due to ultrafast decay of the atomic number density within the spike nanovolume, thus not enabling the buildup of sufficient subsurface pressure as required for driving the correlated emission. For the Be target, an extremely rapid decay of nearly 90% of the initial density within 200 fs from impact is observed. This finding provides further support for the conclusion that the emission of the velocity correlated clusters as observed for the heavier targets takes place within an ultra-short time window of only a few hundreds of femtoseconds, roughly extending from 200 to 500 fs from impact. The lower bound is dictated by the requirement for a relatively slow rate of decay of number density, enabling the buildup of a sufficiently intense pressure spike. The upper bound is dictated by the cooling rate of the spike (still maintaining an extremely high temperature of kT ≥ 1 eV, as experimentally observed) and the onset of the evolution of the impact crater.

Density functional theory study of Al, Ga and in impurities in diamond

As a consequence of its high atomic number density, diamond can incorporate a relatively limited range of impurities as distributed point-defects, chiefly N, B and H. A few other species can be grown-in, and other impurity species incorporated via implantation and annealing. For applications including electronic, electrical and quantum devices, the presence of states deep within the wide band-gap is of importance, and the list of potential colour centres available for exploitation continues to grow. Although B can be grown into diamond at high concentration, study of other group-13 elements is rather limited. In this paper we present the results of modelling of Al, Ga and In. We find all species readily form complexes with vacancies, and exhibit electronic structures that parallel those of the SiV complex. We report electronic structures, electrical levels, optical transitions and hyperfine interactions of the colour centres, as well as reflect upon the thermodynamics of the complexes. We suggest that co-implanting group-13 elements with nitrogen would give rise to the defect charge states with potential for quantum applications.

Laser isotope separation of 203Tl through pulsed laser optical pumping

Isotope separation of 203Tl through pulsed laser optical pumping into the 6s26p2P3/2∘ meta-stable state, followed by pulsed laser ionization, has been theoretically studied through density matrix formalism. The efficiency of the isotope separation process has been compared with the cw laser optical pumping followed by pulsed laser photoionization reported earlier. The effect of peak power density, bandwidth and number density of atoms on the degree of enrichment and the production rate has been systematically studied. The optimum parameters for the efficient laser isotope separation 203Tl have been derived. It has been shown that using this method, it is possible to produce about 1.5 kg/y of 203Tl isotope enriched to 90%.

Dual-energy CT: Impact of detecting bone marrow oedema in occult trauma in the Emergency.

Dual-energy computed tomography (DECT) is an advanced imaging technique that acquires data using two distinct X-ray energy spectra, typically at 80 and 140 kVp, to differentiate materials based on their atomic number and electron density. This capability allows for the enhanced visualisation of various pathologies, including bone marrow oedema (BMO), by providing high-resolution images with notable energy spectral separation while maintaining radiation doses comparable to conventional CT. DECT's ability to create colour-coded virtual non-calcium (VNCa) images has proven particularly valuable in detecting traumatic bone marrow lesions (BMLs) and subtle fractures, offering a reliable alternative or complement to MRI. DECT has emerged as a significant tool in the detection and characterisation of bone marrow pathologies, especially in traumatic injuries. Its ability to generate high-resolution images and distinguish between different tissue types makes it a valuable asset in clinical diagnostics. With its comparable diagnostic accuracy to MRI and the added advantage of reduced examination time and increased availability, DECT represents a promising advancement in the imaging of BMO and related conditions.

Radiation shielding properties of some igneous rocks in isparta province at different gamma energies: Experimental and theoretical study

In this study, our aim is to experimentally and theoretically obtain the gamma radiation shielding properties of some igneous rocks extracted in Isparta, Turkey. In the first stage, experimental measurements were performed using a gamma spectroscopy system containing a NaI(Tl) detector at three different gamma energies (511, 835 and 1275 keV) emitted from two different radioactive sources (22Na and 54Mn). As a result of the experiments, linear attenuation coefficients (LACs) of igneous rocks were obtained. The variation of LAC was investigated in relation to the density and the alkali-silica content of the rocks. The results obtained indicated an increase in the LACs with higher rock and an elevated alkali-silica ratio. Using the experimental LAC results, the half and tenth value layer thickness (HVL and TVL), mean free path (MFP), transmission rate, radiation protection efficiency (RPE) and lead equivalent thickness (dPb) values were calculated. In the second stage of this study, LACs were calculated theoretically with the help of XCOM software using the chemical contents of the selected igneous rocks. The comparison of experimentally obtained LACs with those calculated using the XCOM software, revealed a good agreement between the two methods. In addition, the results obtained with the XCOM software gave information about the variation of the attenuation coefficient in different energy regions. Moreover, effective atomic number (Zeff) and electron density (Ne) parameters were calculated using XCOM and experimental results. Based on the data collected, it can be concluded that the trachy-basalt sample taken from the igneous rocks used in this study is more effective than other rocks in terms of gamma radiation shielding.

Impact of interatomic structural characteristics of aluminosilicate hydrate on the mechanical properties of metakaolin-based geopolymer

This study explores the influence of the interatomic structure of sodium aluminosilicate hydrate (N-A-S-H) with varying silica contents on the mechanical properties of metakaolin-based geopolymer. Geopolymer pastes comprising Si/Al ratios between 2.0 and 3.0 were synthesized. A larger number of Si-O-Si linkages compared to Si-O-Al linkages and a higher atomic number density were found in the geopolymers with higher silica contents, which enhanced the compressive strength of the geopolymer pastes up to the optimal Si/Al ratio of 2.5. The paste with a Si/Al = 2.5 exhibited a greater portion of Q4(1Al and 2Al) and denser morphology compared to the other geopolymer pastes. Furthermore, in-situ high-energy synchrotron X-ray scattering experiments were conducted to assess the elastic modulus of the aluminosilicate structure at a local atomic scale. The modulus value in real space decreases with increasing silica contents up to Si/Al = 2.5 and increases with the presence of excessive unreacted silica fume. The modulus value in reciprocal space for the axial and lateral directions both presented a positive value at the geopolymer comprising a Si/Al ratio higher than 2.5, indicating that the load-bearing property of N-A-S-H changed at higher Si/Al ratios. Moreover, the smallest difference between the strains along the axial and lateral directions was detected for the geopolymer with Si/Al = 2.5 in both the real and reciprocal space, owing to the most interconnected and flexible nanostructure, which led to the highest mechanical strength.

Extracellular volume by dual-energy CT, hepatic reserve capacity scoring, CT volumetry, and transient elastography for estimating liver fibrosis

Our purpose was to compare the efficacy of liver and splenic volumetry (LV and SV), extracellular volume (ECV) on dual-layer spectral-detector CT scoring systems for estimating liver fibrosis (LF) in 45 patients with pathologically staged LF. ECV measured on CT value (HU-ECV), iodine density (ID-ECV), atomic number (Zeff-ECV), and electron density (ED-ECV), LV or SV/body surface area (BSA), albumin bilirubin grade (ALBI), model for end-stage liver disease (MELD) score, aspartate aminotransferase platelet ratio index (APRI), and fibrosis index based on the four factors (FIB-4) were recorded. Transient elastography was measured in 22 patients, and compared to ECV. No correlation was found between transient elastography and all ECVs. Area under the curve (AUC) for estimating F4 on transient elastography was 0.885 (95% CI 0.745–1.000). ALBI was weakly associated with LF (p = 0.451), while MELD (p < 0.001), APRI (p = 0.010), and FIB-4 (p = 0.010) were significantly associated with LF. SV/BSA had a higher AUC than MELD, APRI, and FIB-4 for estimating F4 (AUC = 0.815, 95% CI 0.63–0.999), but MELD (AUC = 0.799, 95% CI 0.634–0.965), APRI (AUC = 0.722, 95% CI 0.561–0.883), and FIB-4 (AUC = 0.741, 95% CI 0.582–0.899) had higher AUCs than ALBI. SV/BSA significantly contributed to differentiation for estimating F4; odds ratio (OR) was 1.304–1.353 (Reader 1–2; R1–R2), whereas MELD significantly contributed to the differentiation between F0–2 and F3–4; OR was 1.528–1.509 (R1–R2). AUC for SV/BSA and MELD combined was 0.877 (95% CI 0.748–1.000). In conclusion, SV/BSA allows for a higher estimation of liver cirrhosis (F4). MELD is more suitable for assessing severe LF (≥ F3–4). The combination of SV/BSA and MELD had a higher AUC than SV/BSA alone for liver cirrhosis (F4).

Sensitive Detection of an Erbium Isotope in an Atomic Beam Using Cavity Ring-Down Spectroscopy.

We have applied cavity ring-down spectroscopy (CRDS) to the study of the 166Er isotope in an atomic beam. These measurements were realized with an external cavity diode laser tuned to the 400.9 nm atomic transition of erbium and a customized high-finesse ring-down optical cavity under vacuum. Erbium atomic beams of different number densities were generated in a tantalum foil micro-crucible within the cavity. Absorbance values of the 166Er isotope between 3 × 10-6 and 7 × 10-5 were measured with a best-case precision on the order of 10-6, which is remarkable when considering the extreme temperatures at which the measurements were conducted, and the short detection path which is characteristic of collimated atomic beams. Number densities of erbium atoms were inferred to be between 2 × 106 and 6 × 107 cm-3. This work demonstrates for the first time the ability of studying dilute atomic beams of refractory materials with high accuracy utilizing CRDS. In these initial studies, we used erbium as a model system, but we expect to extend the proposed approach to the measurement of isotopes of uranium and plutonium for nuclear non-proliferation applications.

Abstract 18308: Effective Atomic Number and Electron Density Number in the Infarcted Myocardium Were Significantly Lower Than Normal Group and Non-Infarcted Myocardium Using the Latest Spectral CT

Introduction: Spectral CT with a dual layer detector can be used to acquire new parameters, such as effective atomic (EAN) and electron density number (EDN). Hypothesis: The EAN and EDN obtained from the latest spectral CT with a dual-layer detector in infarcted myocardium were lower than the myocardial in the normal group and non-infarcted myocardia of patients with previous myocardial infarction (MI). Methods: This retrospective study comprised two groups of patients: those with previous MI (MI group; n = 20; mean age, 73±7 years) and those with clinically suspected coronary artery diseases, no significant stenosis in the coronary arteries, and a normal ECG (normal group; n = 146; age 55±14 years). All patients underwent cardiac spectral CT (7500; Philips) with a dual-layer detector. The EAN and EDN were measured in the interventricular septum (IVS), left ventricle (LV) anterior wall of the (LVAW), and LV lateral wall (LVLW) within a 1.0 mm2 circle at the LV inflow level in axial images during the non-contrast phase and early phase (with a contrast agent). Results: During the non-contrast phase, the EAN in the infarcted myocardium was significantly lower than those in the normal group (P &lt; 0.01) and the non-infarcted myocardia in the MI group (P &lt; 0.05). During the early phase, the EAN in the infarcted myocardium was also significantly lower than those in the normal group (P &lt; 0.01) and the non-infarcted myocardia in the MI group (P &lt; 0.05). During both phases, the EDN in the infarcted myocardium was significantly lower than those in the normal group (P &lt; 0.01) and the non-infarcted myocardia in the MI group (P &lt; 0.05). Conclusion: During both phases, the EAN and EDN in the infarcted myocardium were significantly lower than those in the normal group and the non-infarcted myocardia in the MI group. Using this novel CT approach and the data from the non-contrast phase may aid in detecting abnormal characteristics (such as reduced blood flow, fibrotic changes, or inflammation) in the myocardium.

Abstract 18815: Spectral CT Study to Evaluate Left Atrial Remodeling Using Anatomic and Electron Density Numbers in Patients Scheduled to Undergo Pulmonary Vein Isolation

Introduction: Left atrial (LA) wall remodeling, such as fibrosis and inflammation, may occur in patients with atrial fibrillation (AF) to cause a low voltage AF wave and thickened LA wall. To date, an invasive biopsy has been used to evaluate LA wall remodeling. Hypothesis: Using novel spectral CT with an effective atomic number (EAN) and electron density number (EDN), which are new parameters in addition to CT attenuation, LA anterior wall characteristics can be evaluated. Methods: A total of 13 patients (eight males, mean age 69 years) scheduled for pulmonary vein isolation (PVI) underwent cardiac spectral CT (7500, Philips, Tokyo, Japan). This revealed AF in four patients and a sinus rhythm in nine. From non-contrast, and early and late phase contrast data, EAN and EDN (%EDV) of the LA anterior wall were determined. Results: Mean EANs for the LA anterior wall were 7.35 in patients with AF, and 7.38 in patients with a sinus rhythm, respectively (P=NS), during the non-contrast phase; 8.18 and 8.17, respectively (P=NS), during the early phase; and 8.59 and 8.51, respectively (P=NS) during the late phase. Mean EDNs (%EDW) were 102.7 in patients with AF, and 103,1 in patients with a sinus rhythm, respectively (P=NS) during the non-contrast phase; 102,6 and 103.4, respectively (P=NS) during the early phase; and 103.7 and 103.5, respectively (P=NS) during the late phase. In patients with AF, both LA anterior thickness on CT and LA volume determined by transthoracic echocardiogram had a significant negative correlation with the voltage of AF waves (V2 lead) (R= -0.87 and -0.46, respectively). The EDN, but not EAN, in non-contrast, and early and late phases after contrast material showed a significant negative correlation with the voltage of AF waves (R= -0.74, -0.75, respectively). Conclusions: This is the first study in which characteristics of the LA anterior wall were evaluated by EAN and EDN on spectral CT. As well as LA anterior wall thickening and an enlarged LA volume, the EDN was an indicator of characteristic changes of the LA anterior wall that related to the low voltage of AF waves. This new parameter determined by spectral CT may evaluate characteristics of the LA anterior wall and be a predictor of future occurrence of LA remodeling that is related to the effectiveness of PVI.

Abstract 18374: Effective Atomic Number and Electron Density Number Acquired Using Latest Spectral CT Enable the Differentiation of Infarcted Myocardium and Hypertrophied Myocardium From Normal Myocardium

Introduction: Spectral CT can acquire effective atomic (EAN) and electron density number (EDN). Hypothesis: EAN and EDN using spectral CT enable the differentiation of infarcted myocardium and hypertrophied myocardium from normal myocardium. Methods: We analyzed 146 patients (73 males; mean age 55 ± 14 years old) who had no significant coronary stenosis on CT (7500; Philips) and normal ECG (normal group), 20 patients with previous myocardial infarction (MI) (12 males; mean age 73 ± 7 years old) (MI group), and 10 patients with hypertrophic cardiomyopathy (HCM) (5 males; mean age 66 ± 15 years old) (HCM group). On CT, we measured EAN and EDN in the interventricular septum (IVS), left ventricular (LV) anterior wall (LVAW), and lateral wall (LVLW) within a 1.0 mm2 circle at LV inflow level in the non-contrast and early contrast phase. In MI and HCM groups, EAN and EDN were also measured in the infarcted and hypertrophied myocardium, respectively. Results: In the non-contrast and early contrast phase, the EAN was significantly lower in the infarcted myocardium group than in the normal group (p &lt; 0.01), in the non-infarcted myocardium than in the MI group (p &lt; 0.05) and non-hypertrophied myocardium in the HCM group (p &lt; 0.05), and in the hypertrophic myocardium in the HCM group than in the normal group (p &lt; 0.05) and non-hypertrophic myocardium in the HCM group (p &lt; 0.05). In the non-contrast and early contrast phase, the EDN was also lower in the infarcted myocardium than in the normal group (p &lt; 0.01), non-infarcted myocardium in the MI group (p &lt; 0.05), hypertrophied and non-hypertrophied myocardium in the HCM group (p &lt; 0.05). Conclusion: The use of EAN and EDN enables the differentiation of infarcted myocardium (EAN and EDN) and hypertrophied myocardium (EAN) from normal myocardium even on non-contrast CT alone. The use of EAN and EDN enables the detection of abnormal myocardial characteristics (blood flow decrement, fibrotic change, hypertrophy, and inflammation) on non-contrast CT alone.

Generating a Sustained Oxygen-Stable Atomic Concentration in a High-Temperature Gas Effect Investigation.

Modulated laser absorption spectroscopy is an ideal technique for evaluating flow-field parameters and determining flow-field quality by measuring the atoms dissociated in high-temperature environments. However, to obtain the absolute number density of atoms in the flow field, it is necessary to compare the measured modulated absorption spectroscopy signal with a known atomic concentration and establish a quantitative relationship through concentration calibration. Nevertheless, it remains a challenging task to prepare transient atomic samples with known concentrations that meet the calibration requirements. This study utilized the alternating-current glow discharge technique to dissociate oxygen in the air flow, resulting in the continuous generation of oxygen atoms. The absolute number densities of the generated oxygen atoms were determined by measuring the direct absorption spectra of centered on 777 nm for oxygen atoms. The number densities of the generated atoms were finely tuned by adjusting the discharge parameters. Throughout the 120-min continuous operation of the discharge system, the concentration of excited-state oxygen atoms remained stable within the range of (2.51 ± 0.02) × 108 cm-3, demonstrating the remarkable stability of the transient atomic concentration generated by the glow discharge plasma. This observation suggests that the generated atoms can be utilized as a standardized atomic sample of known concentration for absolute concentration calibration purposes.

Computational discovery of novel U-N-C ternary phases as promising accident-tolerant fuels

Recently, uranium carbonitride solid solution has been recognized as a promising nuclear reactor fuel due to its excellent physicochemical properties. However, due to the complexity of U-N-C ternary system, the research on the structure and properties of uranium carbonitride is still insufficient. In this work, a series of promising accident-tolerant ternary compounds in the U-N-C system were predicted through a combination of first-principles calculations with an evolutionary algorithm. Fifteen dynamically and mechanically stable novel U-N-C ternary compounds with seven chemical compositions, including U-N-C solid solutions and new intermetallic structures, were suggested to be promising for experimental synthesis. For U-N-C solid solutions with rock-salt structures, it was revealed that the lattice expansion and bond length elongation caused by the substitution of carbon atoms for nitrogen atoms can lead to a decrease in elastic moduli and melting point and an increase in toughness. Moreover, two newly identified structures P63/mcm-U3N2C and P2/m-U4NC were considered to be very promising accident-tolerant fuels due to their high mechanical strength, excellent melting point, low thermal expansion coefficient, and high thermal conductivity. The larger atomic number density of P63/mcm-U3N2C enables a higher elastic modulus and a satisfactory melting point than those of rock-salt structures. While for P2/m-U4NC, its unique shorter and stronger U-N/C and U-U bonding leads to its highest mechanical strength and appropriate melting point. Furthermore, the linear thermal expansion coefficients of P2/m-U4NC and P63/mcm-U3N2C are comparable to those of UN and UO2, respectively, and their thermal conductivities increase with temperature, much higher than that of UO2.

Effect of La2O3 on Magnesium Borosilicate glasses glass for radiation shielding materials in nuclear application

As the radiation shielding is important for human health, alternative materials are under research for using this purposes. Thus in this study, Magnesium Borosilicate Glasses were inspected for their radiation defensive mechanism. The glass compositions are 40MgO–30SiO2 – (30-x)B2O3–xLa2O3, where x = 0,2.5,5,7.5 (mol%). Lanthanum (III) oxide, known as lanthana, is an inorganic compound and in it contains the rare earth element lanthanum and oxygen. It can be used as a component of optical materials such as glass as it was used in this study. The variation of the linear attenuation coefficient (LAC) and some other parameters such as half value length (HVL), mean free path (mfp), effective atomic number (Zeff) and Effective electron density (Neff) with the amount of La2O3 (0, 2.5, 5, 7.5 mol%) in glass samples was studied. The Phy-X/PSD program was utilized for this purpose. The results demonstrate that LaO-7.5 (with composition of 40MgO–30SiO2 – 22.5B2O3–7.5La2O3) has the highest LAC value out of the prepared glasses, while LaO-0 has the lowest.

Quantum-Enhanced Magnetometry at Optimal Number Density.

We study the use of squeezed probe light and evasion of measurement backaction to enhance the sensitivity and measurement bandwidth of an optically pumped magnetometer (OPM) at sensitivity-optimal atom number density. By experimental observation, and in agreement with quantum noise modeling, a spin-exchange-limited OPM probed with off-resonance laser light is shown to have an optimal sensitivity determined by density-dependent quantum noise contributions. Application of squeezed probe light boosts the OPM sensitivity beyond this laser-light optimum, allowing the OPM to achieve sensitivities that it cannot reach with coherent-state probing at any density. The observed quantum sensitivity enhancement at optimal number density is enabled by measurement backaction evasion.

Investigating the suitability of newly developed epoxy-based equivalent tissues for newborn and 5-year-old in paediatric radiology

The varied radiological applications of tissue equivalent (TE) materials encompass quality checks, diagnostic imaging, and dose evaluations. However, the availability of compounds representing paediatric patient tissues for scientific use in lower diagnostic photon energy spectra is limited. In this study, several TE substitutes were developed to replicate the radiographic characteristics of neonatal soft tissue (ESST-NB), neonatal skeletal tissue (ESTB-NB), and equivalent tissues of a 5-year-old child (ESST and ESBT, respectively) within these energy ranges. The ORNL stylized computational model series was utilised as the primary reference for obtaining the desired elemental ratios. The density, effective atomic number, CT numbers, and electron densities obtained for the developed tissue substitutes exhibited a close resemblance to those of the reference phantom system, demonstrating a high level of accuracy and agreement. Furthermore, in order to accommodate constraints related to material selection and production, significant correlations were established between the obtained data and the reference values for mass densities, mass attenuation coefficients, and mass energy-absorption coefficients. In comparison to the ORNL reference samples, the neonates TE substitutions showed maximum discrepancies μ/ρ ranging from +1.6% to −3.01% and μen/ρ from +1.15% to −1.4% throughout an energy range from 47 keV to 66 keV. For the TE materials representing a 5-year-old, the corresponding comparable data ranges were +1.09% to −3.02% and +1.92% to −2.53%. These tissues may then be utilised to produce physical phantoms for neonates and 5-year-old as a result of the great concordance established between the newly built TE materials and the reference data.