X-ray Energy Range Research Articles

Dosimetric evaluation of Rhizophora spp. particleboard bonded with animal protein adhesive at X-ray energies below 100 kVp

This research developed a bio-based adhesive (AP) derived from industrial slaughterhouse waste, comprising over 85% protein. The adhesive was characterized by a melting point of 193.14 °C, a neutral pH of 7, and a viscosity comparable to common wood adhesives such as urea-formaldehyde and phenol-formaldehyde. Utilizing this adhesive, a Rhizophora spp. particleboard phantom was produced, featuring wood particles of ≤149 μm, an adhesive concentration of 12%, and a target density of 1 g/cm³, adhering to a standard phantom dimension of 30 cm × 30 cm × 30 cm. The dosimetric properties of this particleboard phantom were subsequently compared with those of water and Perspex phantoms within an X-ray energy range of 60–100 kVp, employing high-sensitivity thermo-luminescent dosimeters (TL–100H). The findings indicated that the percentage depth dose (PDD) values of the AP-Rhizophora spp. particleboard were closely aligned with those of the Perspex and water phantoms, with the greatest discrepancy observed at 60 kVp. Additionally, the half-value layer (HVL) of the particleboard was similar to those of Perspex and water, particularly at diagnostic X-ray energies. These results demonstrate that the AP adhesive is effective for creating Rhizophora spp. particleboard phantoms, exhibiting dosimetric properties comparable to tissue-equivalent materials.

A multi-modal high pressure and high temperature reaction cell for combined x-ray spectroscopy, scattering, and imaging.

A free-standing and compact reaction cell for combined in situ/operando x-ray spectroscopy, scattering, and imaging measurements at high pressures and high temperatures is described. The cell permits measurements under realistic operating conditions (up to 50bar and 1000°C), under static and flow conditions (up to 100 ml/min), over a wide range of hard x-ray energies, variable detection modes (transmission, fluorescence, and scattering), and at all angles of rotation. An operando XAS, x-ray fluorescence, x-ray computed tomography, and x-ray diffraction computed tomography case study on the reduction of a heterogeneous catalyst is presented to illustrate the performance of the reaction cell.

Luminescence Efficiency and Spectral Compatibility of Cerium Fluoride (CeF3) Inorganic Scintillator with Various Optical Sensors in the Diagnostic Radiology X-ray Energy Range

Luminescence Efficiency and Spectral Compatibility of Cerium Fluoride (CeF3) Inorganic Scintillator with Various Optical Sensors in the Diagnostic Radiology X-ray Energy Range

Graphene-based nanocomposites as gamma- and X-ray radiation shield

Commonly used materials for protection against ionizing radiation (gamma and X-ray energy range) primarily rely on high-density materials, like lead, steel, or tungsten. However, these materials are heavy and often impractical for various applications, especially where weight is a key parameter, like in avionics or space technology. Here, we study the shielding properties of an alternative light material—a graphene-based composite with a relatively low density ~ 1 g/cm3. We demonstrate that the linear attenuation coefficient is energy of radiation dependent, and it is validated by the XCOM model, showing relatively good agreement. We also show that the mass attenuation coefficient for selected radiation energies is at least comparable with other known materials, exceeding the value of 0.2 cm2/g for higher energies. This study proves the usefulness of a commonly used model for predicting the attenuation of gamma and X-ray radiation for new materials. It shows a new potential candidate for shielding application.

A Study of Interstellar Medium in the Line of Sight of Transient Neutron Star Low-Mass X-ray Binary, MXB 1659-298, by Timing and Spectral Analysis

This work is dedicated to the study of interstellar medium (ISM) along the line of sight (LOS) of the transient low-mass X-ray binary, MXB 1659-298, capitalizing the high resolving power of XMM-Newton in the soft energy range. We emphasized the analysis of reflection grating spectrometer (RGS) data in the energy range 0.5–2.15 keV, suitable for the study of ISM. The paper includes an explanation of why, in the soft X-ray energy range, only two observations (out of seven) were deemed eligible for analysis. Three absorption lines associated with highly ionized Fe XX (1s22p2-2p2 (3p) 4d), Si XIV (1s2-1s2p), and Mg XI (1s2-1s6p) were identified in the observations, with IDs of 8620701(2001) and 748391601(2015). These new absorption lines and the absorption edge due to the neutral oxygen K edge seen in the spectra validate the multiphase structure of ISM. The predominance of interstellar medium over the ionized absorber is established along the direction of the source. The equivalent hydrogen column density measured is nearly equal to the galactic HI value derived previously. The small value of the ionic column density of Fe, Si, and Mg in the site of the high-temperature region resembles previous findings.

Hard X-ray imaging and tomography at the Biomedical Imaging and Therapy beamlines of Canadian Light Source.

The Biomedical Imaging and Therapy facility of the Canadian Light Source comprises two beamlines, which together cover a wide X-ray energy range from 13 keV up to 140 keV. The beamlines were designed with a focus on synchrotron applications in preclinical imaging and veterinary science as well as microbeam radiation therapy. While these remain a major part of the activities of both beamlines, a number of recent upgrades have enhanced the versatility and performance of the beamlines, particularly for high-resolution microtomography experiments. As a result, the user community has been quickly expanding to include researchers in advanced materials, batteries, fuel cells, agriculture, and environmental studies. This article summarizes the beam properties, describes the endstations together with the detector pool, and presents several application cases of the various X-ray imaging techniques available to users.

Molecular form factor data for tissue equivalent materials

In the diagnostic X-ray energy range, elastic (Coherent) scattering is dominant and can be obtained using an appropriate form factor. When experimental Form Factor data is not available at certain momentum transfer values, molecular form factor data that can be compatible with experimental data should be theoretically obtained. Using these molecular form factor data, molecular coherent scattering coefficients can be calculated, and linear attenuation coefficients of tissue equivalent structures can be estimated. In this study, PMMA, CIRS 70/30, CIRS 50/50, CIRS 30/70, RMI 454, and BR 12, which are equivalent complex molecular structures to human breast tissue, were examined, and the theoretical molecular form factor F(x) values compatible with the experimental form factor values for each were obtained. We believe that our results will find a significant place in the literature and will be beneficial for our future studies and also in the studies of other researchers who make models.

PINK: a tender X-ray beamline for X-ray emission spectroscopy.

A high-flux beamline optimized for non-resonant X-ray emission spectroscopy (XES) in the tender X-ray energy range has been constructed at the BESSY II synchrotron source. The beamline utilizes a cryogenically cooled undulator that provides X-rays over the energy range 2.1 keV to 9.5 keV. This energy range provides access to XES [and in the future X-ray absorption spectroscopy (XAS)] studies of transition metals ranging from Ti to Cu (Kα, Kβ lines) and Zr to Ag (Lα, Lβ), as well as light elements including P, S, Cl, K and Ca (Kα, Kβ). The beamline can be operated in two modes. In PINK mode, a multilayer monochromator (E/ΔE ≃ 30-80) provides a high photon flux (1014 photons s-1 at 6 keV and 300 mA ring current), allowing non-resonant XES measurements of dilute substances. This mode is currently available for general user operation. X-ray absorption near-edge structure and resonant XAS techniques will be available after the second stage of the PINK commissioning, when a high monochromatic mode (E/ΔE ≃ 10000-40000) will be facilitated by a double-crystal monochromator. At present, the beamline incorporates two von Hamos spectrometers, enabling time-resolved XES experiments with time scales down to 0.1 s and the possibility of two-color XES experiments. This paper describes the optical scheme of the PINK beamline and the endstation. The design of the two von Hamos dispersive spectrometers and sample environment are discussed here in detail. To illustrate, XES spectra of phosphorus complexes, KCl, TiO2 and Co3O4 measured using the PINK setup are presented.

Enhancing X-ray radiation protection with novel liquid silicone rubber composites: A promising alternative to lead aprons

This study introduces a lead-free alternative for enhanced radiation protection. While lead aprons effectively attenuate ionizing radiation, concerns regarding flexibility, weight, and environmental hazards persist. In response, the present research is focused on producing an innovative sheet shielding comprised of carefully selected dense metal oxide microparticles (DMOs-MPs) and liquid silicone rubber (LSR). To evaluate the efficacy of the LSR samples, the current study uses rigorous testing procedures, such as microstructure characterization using EDX and FESEM. Furthermore, the study investigated key attenuation parameters within the LSR samples. Radiation protection was greatly and effectively supplied using DMOs-MPs filler (Bi-1 to Bi-7) in LSR samples; this protection reached 99.9% in the X-ray energy range. Due to the unique characteristics of the Bi-7, the results demonstrated that the samples’ shielding efficiency improved with the addition of high atomic number and high-density fillers. It had the greatest attenuation coefficient and density. At 60 keV, Bi-7’s density was 2.980 gcm−3, and its LAC and MAC were 19.2621 cm−1 and 6.4638 cm2/g, respectively. It also had the lowest half-value layer values in the energy range of 60–120 keV. The LSR samples showed effective radiation absorption for different energy levels, indicating that LSR can enhance the flexibility and comfort of the apron while providing adequate radiation protection. The incorporation of the DMOs-MPs with LSR represents an effective contribution and a noteworthy stride to enhance the safety and well-being of medical professionals routinely exposed to ionizing radiation.

Novel 3D-Printed lead-free radiation protection apron in the medical X-ray and thermal neutron energy range

In this study, we employed 3D printing technology to fabricate poly lactic acid (PLA) polymer samples infused with gadolinium oxide nanoparticles at additive rates of 10% and 20%. The objective was to explore their potential as radiation shielding aprons within the medical X-ray and thermal neutron energy spectrum. To facilitate comparisons, a PLA polymer sample with no additive was also produced. The homogeneity and well-defined structures of the PLA samples were observed using SEM and EDS analyses. Additionally, the excellent thermal stability of the proposed test samples was reported. In terms of gamma-ray shielding, there is a remarkable consistency between experiment, theory and simulation outcomes with a maximum discrepancy of approximately 5%. P-PLA-Gd20 sample exhibits attenuation capabilities against X-rays to a level that could serve as an alternative to lead. Additionally, the thermal and fast neutron attenuation effectiveness of the prepared samples were determined. A shielding effectiveness of 100% against thermal neutrons was achieved using a 10 mm sample thickness and the P-PLA-Gd20 sample. The findings consistently highlight the efficacy of the proposed polymer sample with a 20% gadolinium oxide nanoparticle additive, positioning it as a viable and promising alternative to traditional lead aprons.

Technical note: TIGRE-DE for the creation of virtual monoenergetic images from dual-energy cone-beam CT.

Dual-energy (DE)-CBCT represents a promising imaging modality that can produce virtual monoenergetic (VM) CBCT images. VM images, which provide enhanced contrast and reduced imaging artifacts, can be used to assist in soft-tissue visualization during image-guided radiotherapy. This work reports the development of TIGRE-DE, a module in the open-source TIGRE toolkit for the performance of DE-CBCT and the production of VM CBCT images. This module is created to make DE-CBCT tools accessible in a wider range of clinical and research settings. We developed an add-on (TIGRE-DE) to the TIGRE toolkit that performs DE material decomposition. To verify its performance, sequential CBCT scans at 80 and 140kV of a Catphan 604 phantom were decomposed into equivalent thicknesses of aluminum (Al) and polymethyl-methylacrylate (PMMA) basis materials. These basis material projections were used to synthesize VM projections for a range of x-ray energies, which were then reconstructed using the Feldkamp-Davis-Kress (FDK) algorithm. Image quality was assessed by computing Hounsfield units (HU) and contrast-to-noise ratios (CNR) for the material inserts of the phantom and comparing with the constituent 80 and 140kV images. All VM images generated using TIGRE-DE showed good general agreement with the theoretical HU values of the material inserts of the phantom. Apart from the highest-density inserts imaged at the extremes of the energy range, the measured HU values agree with theoretical HUs within the clinical tolerance of±50 HU. CNR measurements for the various inserts showed that, of the energies selected, 60keV provided the highest CNR values. Moreover, 60keV VM images showed average CNR enhancements of 63% and 66% compared to the 80 and 140kV full-fan protocols. TIGRE-DE successfully implements DE-CBCT material decomposition and VM image creation in an accessible, open-source platform.

Development of a flexible composite based on vulcanized silicon casting with bismuth oxide and characterization of its radiation shielding effectiveness in diagnostic X-ray energy range and medium gamma-ray energies

The study aims to develop a novel, lead-free, flexible and lightweight composite shielding material against ionizing radiation. For this, it was used bismuth oxide (Bi2O3) in RTV-2 silicon matrix. The shielding tests were carried out in both diagnostic X-ray energies and intermediate gamma-ray energy range of up to 662 keV to determine the radiation attenuation properties of this material in terms of attenuation ratio, half value layer, tenth value layer, mean free path and lead equivalency of samples in weight of 30%, 40%, 50% in Bi2O3. In the diagnostic X-ray energy range, half value layer, tenth value layer and lead equivalency (in mm Pb) of the produced samples were measured at 80 and 100 kVp narrow beam conditions according to the requirements of EN IEC 61331-1 standard. The results show that lead equivalent values of the produced novel sheets was measured to be 0.16 mm Pb, corresponding to a 6 mm thickness of the flexible sample when it contains 30% wt. Bi2O3 in RTV matrix. The experimental findings for durability and flexibility also indicated that this new RTV-based flexible, lead -free shielding composite can be used safely for especially for manufacturing aprons, garments and thyroid guards used in mammography, radiology, nuclear medicine and dental applications in practice.

XrdPlanner: exploring area detector geometries for powder diffraction and total scattering experiments.

xrdPlanner is a software package designed to aid in the planning and preparation of powder X-ray diffraction and total scattering beam times at synchrotron facilities. Many modern beamlines provide a flexible experimental setup and may have several different detectors available. In combination with a range of available X-ray energies, it often makes it difficult for the user to explore the available parameter space relevant for a given experiment prior to the scheduled beam time. xrdPlanner was developed to provide a fast and straightforward tool that allows users to visualize the accessible part of reciprocal space of their experiment at a given combination of photon energy and detector geometry. To plan and communicate the necessary geometry not only saves time but also helps the beamline staff to prepare and accommodate for an experiment. The program is tailored toward powder X-ray diffraction and total scattering experiments but may also be useful for other experiments that rely on an area detector and for which detector placement and achievable momentum-transfer range are important experimental parameters.

Quantum Efficiency Measurement and Modeling of Silicon Sensors Optimized for Soft X-ray Detection

Hybrid pixel detectors have become indispensable at synchrotron and X-ray free-electron laser facilities thanks to their large dynamic range, high frame rate, low noise, and large area. However, at energies below 3 keV, the detector performance is often limited because of the poor quantum efficiency of the sensor and the difficulty in achieving single-photon resolution due to the low signal-to-noise ratio. In this paper, we address the quantum efficiency of silicon sensors by refining the design of the entrance window, mainly by passivating the silicon surface and optimizing the dopant profile of the n+ region. We present the measurement of the quantum efficiency in the soft X-ray energy range for silicon sensors with several process variations in the fabrication of planar sensors with thin entrance windows. The quantum efficiency for 250 eV photons is increased from almost 0.5% for a standard sensor to up to 62% as a consequence of these developments, comparable to the quantum efficiency of backside-illuminated scientific CMOS sensors. Finally, we discuss the influence of the various process parameters on quantum efficiency and present a strategy for further improvement.

Dose reduction using Saba thyroid shield during diagnostic X-ray energy range: a phantom study

The Saba thyroid shield is a new X-ray dose reduction tool for radiosensitive organs that can reduce the X-ray dose without degrading the image quality. This study investigated its effectiveness in reducing the X-ray dose on the thyroid surface during diagnostic X-ray. This study was conducted in the lab of the Medical Physics Department at Umm-Alqura University. The experiments were performed in the year 2022. A mixed fission product phantom and a solid-state detector were used to measure the radiation dose on the thyroid surface during diagnostic X-ray using a tube voltage within 40–120 kVp. The effectiveness of the Saba thyroid shield was examined in two settings: in-field and out-of-field. Measurements were conducted for these two settings without and with the Saba thyroid shield, and the attenuation percentages were computed. Analysis of covariance was used to test the tool’s effectiveness in X-ray dose reduction. The average in- and out-of-field dose attenuation percentages using the Saba thyroid shield were 80.12 ± 0.12% and 81.13 ± 0.18%, respectively. A significant difference was shown between the measurements done without and with the Saba thyroid shield (p = 0.000) for both the in-field and out-of-field doses. The in-field and out-of-field dose reduction levels using the shield were approximately the same. This study demonstrated that the newly developed Saba thyroid shield made of copper and bismuth effectively reduces both the in-field and out-of-field radiation doses.

Hybrid-Vlasov simulation of soft X-ray emissions at the Earth’s dayside magnetospheric boundaries

Solar wind charge exchange produces emissions in the soft X-ray energy range which can enable the study of near-Earth space regions such as the magnetopause, the magnetosheath and the polar cusps by remote sensing techniques. The Solar wind–Magnetosphere–Ionosphere Link Explorer (SMILE) and Lunar Environment heliospheric X-ray Imager (LEXI) missions aim to obtain soft X-ray images of near-Earth space thanks to their Soft X-ray Imager (SXI) instruments. While earlier modeling works have already simulated soft X-ray images as might be obtained by SMILE SXI during its mission, the numerical models used so far are all based on the magnetohydrodynamics description of the space plasma.To investigate the possible signatures of ion-kinetic-scale processes in soft X-ray images,we use for the first time a global hybrid-Vlasov simulation of the geospace from the Vlasiator model. The simulation is driven by fast and tenuous solar wind conditions and purely southward interplanetary magnetic field. We first produce global X-ray images of the dayside near-Earth space by placing a virtual imaging satellite at two different locations,providing meridional and equatorial views. We then analyze regional features present in the images and show that they correspond to signatures in soft X-ray emissions of mirror mode wave structures in the magnetosheath and flux transfer events (FTEs) at the magnetopause. Our results suggest that, although the time scales associated with the motion of those transient phenomena will likely be significantly smaller than the integration time of the SMILE and LEXI imagers, mirror-mode structures and FTEs can cumulatively produce detectable signatures in the soft X-ray images. For instance, a local increase by 30% in the proton density at the dayside magnetopause resulting from the transit of multiple FTEs leads to a 12% enhancement in the line-of-sight- and timeintegrated soft X-ray emissivity originating from this region. Likewise, a proton density increase by 14% in the magnetosheath associated with mirror-mode structures can result in an enhancement in the soft X-ray signal by 4%. These are likely conservative estimates, given that the solar wind conditions used in the Vlasiator run can be expected to generate weaker soft X-ray emissions than the more common denser solar wind. These results will contribute to the preparatory work for the SMILE and LEXI missions by providing the community with quantitative estimates of the effects of small-scale, transient phenomena occurring on the dayside.

Extended X-ray absorption fine structure (EXAFS) measurement of Cu metal foil using thermal wave detector: A comparative study

In this study, we compared two methods for measuring EXAFS spectra, which provide insights into material local structures. The conventional transmission mode used a synchrotron beam as a source and ionization chambers as detectors. Alternatively, we employed thermal wave detectors, specifically a pyroelectric crystal, for a simpler approach. The experiment was conducted using a LiNbO3 crystal at a synchrotron facility operating in the hard X-ray energy range. The chopping frequency of the X-ray beam was set at 1.8 Hz to optimize data collection. We discussed the challenges of selecting the appropriate chopping frequency for EXAFS measurements and the importance of detector sensitivity. We shared results from experiments at various chopping frequencies, highlighting the suitability of pyroelectric detectors. The study demonstrated the feasibility of using pyroelectric detectors for EXAFS measurements, providing valuable data with minimal artifact effects. The findings contribute to the understanding of material local structures and open possibilities for further exploration of thermal wave detectors in continuous theta scan applications.

Metallic artifacts-free spectral computed tomography angiography based on renal clearable bismuth chelate

Computed tomography angiography (CTA) is one of the most important diagnosis techniques for various vascular diseases in clinic. However, metallic artifacts caused by metal implants and calcified plaques in more and more patients severely hinder its wide applications. Herein, we propose an improved metallic artifacts-free spectral CTA technique based on renal clearable bismuth chelate (Bi-DTPA dimeglumine) for the first time. Bi-DTPA dimeglumine owns the merits of ultra-simple synthetic process, approximately 100% of yield, large-scale production capability, good biocompatibility, and favorable renal clearable ability. More importantly, Bi-DTPA dimeglumine shows superior contrast-enhanced effect in CTA compared with clinical iohexol at a wide range of X-ray energies especially in higher X-ray energy. In rabbits’ model with metallic transplants, Bi-DTPA dimeglumine assisted-spectral CTA can not only effectively mitigate metallic artifacts by reducing beam hardening effect under high X-ray energy, but also enables accurate delineation of vascular structure. Our proposed strategy opens a revolutionary way to solve the bottleneck problem of metallic artifacts in CTA examinations.

Characterization of iLGADs using soft X-rays

Experiments at synchrotron radiation sources and X-ray Free-Electron Lasers in the soft X-ray energy range (250 eV–2 keV) stand to benefit from the adaptation of the hybrid silicon detector technology for low energy photons. Inverse Low Gain Avalanche Diode (iLGAD) sensors provide an internal gain, enhancing the signal-to-noise ratio and allowing single photon detection below 1 keV using hybrid detectors. In addition, an optimization of the entrance window of these sensors enhances their quantum efficiency (QE).In this work, the QE and the gain of a batch of different iLGAD diodes with optimized entrance windows were characterized using soft X-rays at the Surface/Interface:Microscopy beamline of the Swiss Light Source synchrotron. Above 250 eV, the QE is larger than 55% for all sensor variations, while the charge collection efficiency is close to 100%. The average gain depends on the gain layer design of the iLGADs and increases with photon energy. A fitting procedure is introduced to extract the multiplication factor as a function of the absorption depth of X-ray photons inside the sensors. In particular, the multiplication factors for electron- and hole-triggered avalanches are estimated, corresponding to photon absorption beyond or before the gain layer, respectively.

A low noise CMOS camera system for 2D resonant inelastic soft X-ray scattering

Resonant Inelastic X-ray Scattering (RIXS) is a powerful spectroscopic technique to study quantum properties of materials in the bulk. A novel variant of RIXS, called 2D RIXS, enables concurrent measurement of the scattered X-ray spectrum for a wide range of input energies, improving on the typically low throughput of 1D RIXS. In the soft X-ray domain, 2D RIXS demands an X-ray camera system with small pixels, large area, high quantum efficiency and low noise to limit the false detection rate in long duration exposures. We designed and implemented a 7.5 Megapixel back-illuminated CMOS detector with 5 μm pixels and high quantum efficiency in the 200–1,000 eV X-ray energy range for the QERLIN 2D RIXS spectrometer at the Advanced Light Source. The QERLIN beamline and detector are currently in commissioning. The camera noise from in-situ 3 s long dark exposures is 7e− or less and the leakage current is 6.5 × 10−3 e−/(pixel ∙ s). For individual 500 eV X-rays, the expected efficiency is greater than 75% and the false detection rate is ∼1 × 10−5 per pixel.