Quantum Beam Science

10 pages, 1879 KiB

Open AccessArticle

An Electrospinning Sample Delivery Device for Synchrotron-Based Biomacromolecule Serial Crystallography Research

by Li Yu, Zhijun Wang, Qin Xu, Bo Sun, Qingjie Xiao, Weiwei Wang, Yuzhu Wang, Qisheng Wang and Jianhua He

Quantum Beam Sci. 2025, 9(2), 17; https://doi.org/10.3390/qubs9020017 - 5 May 2025

Abstract

Serial crystallography is a rapidly advancing experimental technology that has seen significant development in recent years. This technique enables the continuous delivery of a series of protein crystal samples to the X-ray beam, allowing for the collection of diffraction data from a large [...] Read more.

Serial crystallography is a rapidly advancing experimental technology that has seen significant development in recent years. This technique enables the continuous delivery of a series of protein crystal samples to the X-ray beam, allowing for the collection of diffraction data from a large number of crystals at ambient temperature. Despite its advancements, serial crystallography still possesses considerable potential for further development within synchrotron radiation platforms. Currently, several challenges hinder the progress of this technology, including the preparation of numerous microcrystal samples, methods for sample delivery, data acquisition efficiency, and data processing techniques. The device introduced in this paper is designed to facilitate serial crystallographic experiments at the synchrotron radiation station, employing electrospinning in the vacuum cavity to reduce the average flux, mitigate the effects of air ionization on the Taylor cone, and enhance the stability of Taylor cone during the data acquisition process. The diffraction pattern of lysozyme crystals was successfully acquired with this device at the beamlines of the Shanghai Synchrotron Radiation Facility (SSRF). Full article

(This article belongs to the Section Instrumentation and Facilities)

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13 pages, 2975 KiB

Open AccessArticle

Impact of Pseudo-Random Number Generators on Dosimetric Parameters in Validation of Medical Linear Accelerator Head Simulation for 6 MV Photons Using the GATE/GEANT4 Platform

by Meriem Tantaoui, Mustapha Krim, El Mehdi Essaidi, Othmane Kaanouch, Mohammed Reda Mesradi, Abdelkrim Kartouni and Souha Sahraoui

Quantum Beam Sci. 2025, 9(2), 16; https://doi.org/10.3390/qubs9020016 - 5 May 2025

Abstract

Monte Carlo simulation relies on pseudo-random number generators. In general, the quality of these generators can have a direct impact on simulation results. The GATE toolbox, widely adopted in radiotherapy, offers three generators from which users can choose: Mersenne Twister, Ranlux-64, and James-Random. [...] Read more.

Monte Carlo simulation relies on pseudo-random number generators. In general, the quality of these generators can have a direct impact on simulation results. The GATE toolbox, widely adopted in radiotherapy, offers three generators from which users can choose: Mersenne Twister, Ranlux-64, and James-Random. In this study, we used these generators to simulate the head of a medical linear accelerator for 6 MV photons in order to assess their potential impact on the results obtained in radiotherapy simulation. Simulations were conducted for four different field openings. The simulations included a linac head model and a water phantom, all components of the head of the medical linear accelerator, and a water phantom placed at a distance of 100 cm from the electron source. Statistical analysis based on normal probability and Bland–Altman plots were used to compare dose distributions in the voxelized water phantom obtained by each generator. Experimental data (dose profiles, percentage dose at depth, and other dosimetric parameters) were measured using an appropriate quality assurance protocol for comparison with the different simulations. The evaluation of dosimetric criteria shows significant variations, particularly in the physical penumbra of the dose profile for large fields. The gamma index analysis highlights significant distinctions in generator performance. In all simulations, the average time of the primary particle generation rate, number of tracks, and steps in the simulation of different random number generators showed differences. The Mersenne Twister generator was distinguished by high performance in several aspects, particularly in terms of execution time, primary particle production, track and step production flow rate, and coming closer to the experimental results. Regarding computational time, the simulation using the Mersenne Twister generator was about 18% faster than the one using the James-Random generator and 27% faster than the simulation using the Ranlux-64 generator. This suggests that this generator is the most reliable for accurate and fast modeling of the medical linear accelerator head for 6 MV energy. Full article

(This article belongs to the Section Radiation Scattering Fundamentals and Theory)

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15 pages, 10319 KiB

Open AccessFeature PaperArticle

Residual Stresses of Small-Bore Butt-Welded Piping Measured by Quantum Beam Hybrid Method

by Kenji Suzuki, Yasufumi Miura, Hidenori Toyokawa, Ayumi Shiro, Takahisa Shobu, Satoshi Morooka and Yuki Shibayama

Quantum Beam Sci. 2025, 9(2), 15; https://doi.org/10.3390/qubs9020015 - 2 May 2025

Abstract

Cracks due to stress corrosion cracking in stainless steels are becoming a problem not only in boiling water reactors but also in pressurized water reactor nuclear plants. Stress improvement measures have been implemented mainly for large-bore welded piping, but in the case of [...] Read more.

Cracks due to stress corrosion cracking in stainless steels are becoming a problem not only in boiling water reactors but also in pressurized water reactor nuclear plants. Stress improvement measures have been implemented mainly for large-bore welded piping, but in the case of small-bore welded piping, post-welding stress improvement measures are often not possible due to dimensional restrictions, etc. Therefore, knowing the actual welding residual stresses of small-bore welded piping regardless of reactor type is essential for the safe and stable operation of nuclear power stations, but there are only a limited number of examples of measuring the residual stresses. In this study, austenitic stainless steel pipes with an outer diameter of 100 mm and a wall thickness of 11.1 mm were butt-welded. The residual stresses were measured by the strain scanning method using neutrons. Furthermore, to obtain detailed residual stresses near the penetration bead where the maximum stress is generated, the residual stresses near the inner surface of the weld were measured using the double-exposure method (DEM) with hard X-rays of synchrotron radiation. A method using a cross-correlation algorithm was proposed to determine the accurate diffraction angle from the complex diffraction patterns from the coarse grains, dendritic structures, and plastic zones. A quantum beam hybrid method (QBHM) was proposed that uses the circumferential residual stresses obtained by neutrons and the residual stresses obtained by the double-exposure method in a complementary use. The residual stress map of welded piping measured using the QBHM showed an area where the axial tensile residual stress exists from the neighborhood of the penetration bead toward the inside of the welded metal. This result could explain the occurrence of stress corrosion cracking in the butt-welded piping. A finite element analysis of the same butt-welded piping was performed and its results were compared. There is also a difference between the simulation results of residual stress using the finite element method and the measurement results using the QBHM. This difference is because the measured residual stress map also includes the effect of the stress of each crystal grain based on elastic anisotropy, that is, residual micro-stress. Full article

(This article belongs to the Section Engineering and Structural Materials)

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14 pages, 2505 KiB

Open AccessArticle

Generation of Coupled Nonlinear Oscillations in Charged-Particle Beam by Crossed Magnetic Fields

by Alexander R. Karimov, Grigoriy O. Buyanov, Alexander E. Shikanov and Konstantin I. Kozlovskij

Quantum Beam Sci. 2025, 9(2), 14; https://doi.org/10.3390/qubs9020014 - 28 Apr 2025

Abstract

Based on the cold-fluid hydrodynamic description, the interaction of a non-relativistic charged-particle beam with crossed magnetic fields is studied. This process results in the transfer of energy/momentum from the field to the beam, which, in turn, enhances the beam’s own electrostatic oscillations. This [...] Read more.

Based on the cold-fluid hydrodynamic description, the interaction of a non-relativistic charged-particle beam with crossed magnetic fields is studied. This process results in the transfer of energy/momentum from the field to the beam, which, in turn, enhances the beam’s own electrostatic oscillations. This paper investigates the development features of such coupled axial and radial oscillations near resonant frequencies. The necessary conditions for the resonant amplification of this beam’s natural oscillations are identified. Such a process may be used for the creation of effective radiation sources. Full article

(This article belongs to the Special Issue New Challenges in Electron Beams)

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11 pages, 4800 KiB

Open AccessFeature PaperArticle

The Impact of Superconducting Properties of Micron-Scale Masked Proton Irradiation on BaTiO₃-Doped YBCO Film

by Di Chen, Paththini Kuttige S. Nonis, Sudaice Kazibwe, Liangzi Deng and Ching-Wu Chu

Quantum Beam Sci. 2025, 9(2), 13; https://doi.org/10.3390/qubs9020013 - 18 Apr 2025

Abstract

This study investigates the effects of 60 keV proton irradiation on BaTiO₃-doped YBa₂Cu₃O_7−δ (YBCO) films using masks with micron-scale holes to create controlled defect patterns aimed at enhancing superconducting properties. Contrary to expectations, masked irradiation resulted [...] Read more.

This study investigates the effects of 60 keV proton irradiation on BaTiO₃-doped YBa₂Cu₃O_7−δ (YBCO) films using masks with micron-scale holes to create controlled defect patterns aimed at enhancing superconducting properties. Contrary to expectations, masked irradiation resulted in a reduction in the critical current density (J_c), while unmasked irradiation demonstrated improvement, consistent with previous studies. Notably, no improvement was observed at 2 T around liquid nitrogen temperature. These observations highlight the challenges of employing micron-scale masks in defect engineering and underscore the need for further refinement to achieve the desired performance enhancement. Insights from this study contribute to advancing defect engineering techniques for improving YBCO’s performance in high-field applications, including fusion energy systems. Full article

(This article belongs to the Special Issue Quantum Beam and Its Applications for Quantum Technologies)

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13 pages, 2235 KiB

Open AccessArticle

Optimization of DD-110 Neutron Generator Output for Boron Neutron Capture Therapy Using Monte Carlo Simulation

by Hossam Donya and Muhammed Umer

Quantum Beam Sci. 2025, 9(2), 12; https://doi.org/10.3390/qubs9020012 - 15 Apr 2025

Abstract

Boron neutron capture therapy (BNCT) is a specialized cancer treatment that leverages the high absorption cross-section of boron for thermal neutrons. When boron captures neutrons, it undergoes a nuclear reaction that produces alpha particles and lithium ions, which have high linear energy transfer [...] Read more.

Boron neutron capture therapy (BNCT) is a specialized cancer treatment that leverages the high absorption cross-section of boron for thermal neutrons. When boron captures neutrons, it undergoes a nuclear reaction that produces alpha particles and lithium ions, which have high linear energy transfer (LET) and can effectively damage nearby cancer cells while minimizing harm to surrounding healthy tissues. This targeted approach makes BNCT particularly advantageous for treating tumors situated in sensitive areas where traditional radiation therapies may pose risks to critical structures. In this study, the deuterium–deuterium (DD) neutron generator, specifically the DD-110 model (neutron yield Y = 1 × 10¹⁰ n/s), served as the neutron source for BNCT. The fast neutrons produced by this generator were thermalized to the epithermal energy range using a beam-shaping assembly (BSA). The BSA was designed with a moderator composed of 32 cm of MgF₂, a reflector made of 76 cm of Pb, and filters including 3 cm of Pb and 1.52 cm of Bi. A collimator, featuring a 10 cm high Pb cone frustum with a 12 cm aperture diameter, was also employed to optimize beam characteristics. The entire system’s performance was modeled and simulated using the MCNPX code, focusing on parameters both in-air and in-phantom to evaluate its efficacy. The findings indicated that the BSA configuration yielded an optimal thermal-to-epithermal flux ratio (

φ_{t h e r}

/

φ_{e p t h}

) of 0.19, a current-to-flux ratio of 0.87, and a gamma dose-to-epithermal flux ratio of 1.71 × 10⁻¹³ Gy/cm², all aligning with IAEA recommendations. The simulated system showed acceptable ratios for

φ_{t h e r}

/

φ_{e p t h}

, gamma dose to epithermal flux, and beam collimation. Notably, the advantage depth was recorded at 5.5 cm, with an advantage ratio of 2.29 and an advantage depth dose rate of 4.1 × 10⁻⁴ Gy.Eq/min. The epithermal neutron flux of D110 exceeded D109, but D110’s fast neutron contamination increased ~6.6 times. On the other hand, D110’s gamma contamination decreased by 30%. Based on these findings, optimizing neutron source characteristics is crucial for BNCT efficacy. Future research should focus on developing advanced neutron generators that balance these factors, aiming to produce optimal neutron yields for enhanced treatment outcomes and broader applicability. Full article

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17 pages, 4136 KiB

Open AccessArticle

Simulation Study on Dose and LET of Neutron Irradiation for Biological Experiments Using Spallation, Reactor, and Compact Neutron Sources

by May Sweet, Kenji Mishima, Masahide Harada, Keisuke Kurita, Hiroshi Iikura, Seiji Tasaki and Norio Kikuchi

Quantum Beam Sci. 2025, 9(2), 11; https://doi.org/10.3390/qubs9020011 - 8 Apr 2025

Abstract

Neutron beams, being electrically neutral and highly penetrating, offer unique advantages for the irradiation of biological species such as plants, seeds, and microorganisms. We comprehensively investigated the potential of neutron irradiation for inducing genetic mutations by using simulations of spallation, reactor, and compact [...] Read more.

Neutron beams, being electrically neutral and highly penetrating, offer unique advantages for the irradiation of biological species such as plants, seeds, and microorganisms. We comprehensively investigated the potential of neutron irradiation for inducing genetic mutations by using simulations of spallation, reactor, and compact neutron sources based on J-PARC BL10, the JRR-3 TNRF, and KUANS. We analyzed neutron flux, energy deposition rates, and Linear Energy Transfer (LET) distributions. The KUANS simulation demonstrated the highest dose rate of 17 Gy/h, significantly surpassing that obtained at BL10, due to the large solid angle achieved with optimal sample placement. The findings highlight KUANS’s suitability for efficiently inducing specific genetic mutations and neutron breeding, particularly for inducing targeted mutations in biological samples, also on account of its LET range of 20–70 keV/μm. Our results emphasize the importance of choosing neutron sources based on LET requirements to maximize mutation induction efficiency. This research study shows the potential of compact neutron sources such as KUANS for effective biological irradiation and neutron breeding, offering a viable alternative to larger facilities. The neutron filters used at BL10 and the TNRF effectively exclude low-energy neutrons while keeping the high-LET component. The neutron capture reaction, ¹⁴N(n,p)¹⁴C, was found to be the main dose contributor under thermal neutron-dominated conditions. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2024)

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4 pages, 193 KiB

Open AccessEditorial

Analysis of Strain, Stress and Texture with Quantum Beams, 2nd Edition

by Kenji Suzuki

Quantum Beam Sci. 2025, 9(1), 10; https://doi.org/10.3390/qubs9010010 - 12 Mar 2025

Abstract

Welcome to the Special Issue of Quantum Beam Science, entitled “Analysis of Strain, Stress and Texture with Quantum Beams, 2nd Edition” [...] Full article

(This article belongs to the Special Issue Analysis of Strain, Stress and Texture with Quantum Beams, 2nd Edition)

18 pages, 3409 KiB

Open AccessReview

Advancements and Challenges in Colloidal Quantum Dot Infrared Photodetectors: Strategies for Short-Wave Infrared, Mid-Wave Infrared, and Long-Wave Infrared Applications

by Lijing Yu, Pin Tian and Kun Liang

Quantum Beam Sci. 2025, 9(1), 9; https://doi.org/10.3390/qubs9010009 - 3 Mar 2025

Abstract

Colloidal quantum dots (QDs) have emerged as promising materials for the development of infrared photodetectors owing to their tunable band gaps, cost-effective manufacturing, and ease of processing. This paper provides a comprehensive overview of the fundamental properties of quantum dots and the operating [...] Read more.

Colloidal quantum dots (QDs) have emerged as promising materials for the development of infrared photodetectors owing to their tunable band gaps, cost-effective manufacturing, and ease of processing. This paper provides a comprehensive overview of the fundamental properties of quantum dots and the operating principles of various infrared detectors. We review the latest advancements in short-wave infrared (SWIR), mid-wave infrared (MWIR), and long-wave infrared (LWIR) detectors employing colloidal quantum dots. Despite their potential, these detectors face significant challenges compared to conventional infrared technologies. Current commercial applications are predominantly limited to the near-infrared and short-wave bands, with medium- and long-wave applications still under development. The focus has largely been on lead and mercury-based quantum dots, which pose environmental concerns, underscoring the need for high-performance, non-toxic materials. Looking forward, the development of large array and small pixel detectors and improving compatibility with readout circuits are critical for future progress. This paper discusses these hurdles and offers insight into potential strategies to overcome them, paving the way for next-generation infrared sensing technologies. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2024)

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14 pages, 5366 KiB

Open AccessArticle

Investigation of Mn²⁺-Doped Stearic-Acid Through XRD, Raman, and FT-IR, and Thermal Studies

by Rodrigo M. Rocha, Marinaldo V. de Souza Junior, Luiz F. L. Silva, Paulo T. C. Freire, Gardênia S. Pinheiro, Waldomiro Paschoal, Jr., Francisco F. de Sousa and Sanclayton G. C. Moreira

Quantum Beam Sci. 2025, 9(1), 8; https://doi.org/10.3390/qubs9010008 - 1 Mar 2025

Abstract

In this research, we investigated the influence of Mn²⁺ ions on the packing in stearic acid (SA) crystals through the use of Raman spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The crystals investigated were obtained utilizing the slow evaporation [...] Read more.

In this research, we investigated the influence of Mn²⁺ ions on the packing in stearic acid (SA) crystals through the use of Raman spectroscopy, X-ray diffraction (XRD), and Fourier transform infrared (FT-IR) spectroscopy. The crystals investigated were obtained utilizing the slow evaporation methodology in a hexane solution under varying manganese (Mn) concentrations sourced from MnSO₄ 5H₂O (0.5, 1.0, 1.5, 2.0, 4.0, and 6.0%). XRD studies indicated that all SA crystals were grown in the B_m form (monoclinic), favoring the gauche conformation in molecular packing. Additionally, crystalline lattice modifications were observed through Raman spectral changes in the low-vibrational energy region. Variations in the intensities and Raman shifts in two lattice vibrational modes, centered at approximately 59 and 70 cm⁻¹, revealed that two types of hydrogen bonds are distinctly affected within the crystalline lattice. Furthermore, the unit cell parameters (a, b, c, and β) were determined via Rietveld refinement, and their behavior was analyzed as a function of Mn concentration. The results indicated that Mn²⁺ ions exert a strain and deformation effect on the unit cell. Lastly, differential scanning calorimetry (DSC) was employed to evaluate the thermal stability of the B_m form of SA crystals. Full article

(This article belongs to the Section Engineering and Structural Materials)

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14 pages, 2521 KiB

Open AccessArticle

Dosimetric Study of Flattened Versus Unflattened Filter-Free Medical Linear Accelerator: Experimental Measurements and Monte Carlo Calculations

by Mohammed Halato, Ibrahim I. Suliman, Abdelmonim Artoli, Francesco Longo and Gianrossano Giannini

Quantum Beam Sci. 2025, 9(1), 7; https://doi.org/10.3390/qubs9010007 - 24 Feb 2025

Abstract

A dosimetric study compared flattened filter (FF) and unflattened filter-free (FFF) 18 MV medical linear accelerators (LINAC) using BEAMnrc Monte Carlo (MC) calculations and experimental measurements. BEAMnrc MC simulations were initially validated against experimental measurements for an 18 MV FF LINAC, with parameters [...] Read more.

A dosimetric study compared flattened filter (FF) and unflattened filter-free (FFF) 18 MV medical linear accelerators (LINAC) using BEAMnrc Monte Carlo (MC) calculations and experimental measurements. BEAMnrc MC simulations were initially validated against experimental measurements for an 18 MV FF LINAC, with parameters such as the percentage depth dose (PDD) and beam profile measured and calculated per the International Atomic Energy Agency (IAEA) dosimetry protocol TRS 398. Following the validation of the LINAC and water phantom models for MC simulations, BEAMnrc MC calculations were performed to compare the FF and FFF 18 MV LINAC parameters. The results indicate that the BEAMnrc MC accurately simulated the LINAC model, with PDD uncertainties within 2%. Beam flatness differences between the MC simulations and measurements in the plateau region were within 3% and within 2 mm in the penumbra region. The PDD data show that the 18 MV FFF beam delivered a higher dose rate in the buildup region than the FF beam, while beam profile measurements indicate lower out-of-field doses for FFF beams, especially in the 20 × 20 cm² field. These findings provide crucial dosimetric data for an 18 MV FFF LINAC, which is useful for quality assurance and beam matching, and offer a methodology for quantitatively comparing the dosimetry properties of an individual 18 MV FFF LINAC to reference data. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2024)

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18 pages, 5821 KiB

Open AccessFeature PaperReview

Intensity Enhancement and Q-Range Extension in Pinhole SANS Instruments with Neutron Focusing Lenses

by Aurel Radulescu

Quantum Beam Sci. 2025, 9(1), 6; https://doi.org/10.3390/qubs9010006 - 12 Feb 2025

Cited by 1

Abstract

Soft matter and biological materials are characterized by a complex morphology consisting of multiple structural levels that are either hierarchically organized or coexist over a length scale from a few Å up to the size of µm. For a structural characterization of such [...] Read more.

Soft matter and biological materials are characterized by a complex morphology consisting of multiple structural levels that are either hierarchically organized or coexist over a length scale from a few Å up to the size of µm. For a structural characterization of such morphologies, an extended Q-range must be covered in X-ray and neutron scattering experiments. Neutrons offer the unique advantage of contrast variation and matching by D-labeling, which is of great value for the characterization of hydrocarbon systems, which are essentially the constituents of soft matter and biological materials. The combination of ultra- and small-angle neutron scattering techniques (USANS and SANS) on complementary beamlines has long been used for such experimental investigations. However, the combined use of USANS and SANS methods at the same beamline for simultaneous acquisition of scattering data over a wide Q-range is necessary when working with sensitive or expensive samples that require special preparation or in situ treatment during the structural characterization. For this reason, several pinhole SANS instruments have been equipped with focusing lenses to allow additional measurements at lower Q values, in the USANS range. The use of neutron lenses has the additional advantage of enhancing the intensity on the sample by providing the ability to work with larger samples while maintaining the same resolution as in pinhole mode. The experimental approach for using neutron lenses to enhance the intensity and extend the Q-range to lower values than in pinhole mode is presented using examples from studies on the pinhole SANS diffractometers equipped with focusing lenses. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2024)

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14 pages, 2844 KiB

Open AccessFeature PaperArticle

Piecewise Linear Approximation of Elliptical Neutron Guides—A Case Study for BIFROST at ESS

by Daniel Lomholt Christensen, Rebekka Frøystad, Martin Andreas Olsen, Kristine Marie Løfgren Krighaar, Asla Husgard, Mads Bertelsen, Rasmus Toft-Petersen and Kim Lefmann

Quantum Beam Sci. 2025, 9(1), 5; https://doi.org/10.3390/qubs9010005 - 11 Feb 2025

Abstract

Previous studies of elliptical neutron guides have shown that they transport neutrons with fewer reflections than traditional guides with a constant cross section, thus reducing neutron losses. True elliptical guides, however, are tedious to produce. Therefore, we use the neutron simulation package McStas [...] Read more.

Previous studies of elliptical neutron guides have shown that they transport neutrons with fewer reflections than traditional guides with a constant cross section, thus reducing neutron losses. True elliptical guides, however, are tedious to produce. Therefore, we use the neutron simulation package McStas to investigate the effect of approximating the elliptical shape by linearly tapering guide pieces. The study concerns both simple model guides and a more complex guide system corresponding to that of the BIFROST instrument, currently under construction at the European Spallation Source (ESS). Our results show that it is possible to split a simple elliptical guide into linearly tapering pieces with lengths of up to 3 m, without sacrificing transport properties. We also find that the piecewise tapering guides in some cases will have a slightly higher neutron transfer than the perfectly shaped guides for shorter wavelengths. For a ballistic guide systems with elliptical expanding and focusing sections, and for the BIFROST guide, linearly tapered pieces of 0.5 m can be used with no cost in transport properties or penalties in form of inhomogeneous phase space, but with significantly lower production costs. Full article

(This article belongs to the Section Instrumentation and Facilities)

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9 pages, 373 KiB

Open AccessArticle

Model for Proton Acceleration in Strongly Self-Magnetized Sheath Produced by Ultra-High-Intensity Sub-Picosecond Laser Pulses

by Artem V. Korzhimanov

Quantum Beam Sci. 2025, 9(1), 4; https://doi.org/10.3390/qubs9010004 - 20 Jan 2025

Abstract

Recently, it has been experimentally shown that the sheath acceleration of protons from ultra-thin metal targets irradiated by sub-picosecond laser pulses of intensities above

10^{21}

W/cm² is suppressed compared to well-established models. This detrimental effect has been attributed to a self-generation [...] Read more.

Recently, it has been experimentally shown that the sheath acceleration of protons from ultra-thin metal targets irradiated by sub-picosecond laser pulses of intensities above

10^{21}

W/cm² is suppressed compared to well-established models. This detrimental effect has been attributed to a self-generation of gigagauss-level quasi-static magnetic fields in expanded plasmas on the rear side of a target. Here we present a set of numerical simulations which support this statement. Based on 2D full-scale PIC simulations, it is shown that the scaling of a cutoff energy of the accelerated protons with intensity deviates from a well-established Mora model for laser pulses with a duration exceeding 500 fs. This deviation is showed to be connected to effective magnetization of the hottest electrons producing at the maximum of the laser pulse intensity. We propose a modification of the Mora model which incorporates the effect of the possible electron magnetization. Comparing it to the simulation results shows that by appropriately choosing a single fitting parameter, the model produces results that quantitatively coincide with simulations. Full article

(This article belongs to the Special Issue Laser-Assisted Facilities)

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17 pages, 7192 KiB

Open AccessArticle

Effect of Dy³⁺ Ions on Structural, Thermal and Spectroscopic Properties of L-Threonine Crystals: A Visible Light-Emitting Material

by João G. de Oliveira Neto, Otávio C. da Silva Neto, Jéssica A. O. Rodrigues, Jailton R. Viana, Alysson Steimacher, Franciana Pedrochi, Francisco F. de Sousa and Adenilson O. dos Santos

Quantum Beam Sci. 2025, 9(1), 3; https://doi.org/10.3390/qubs9010003 - 13 Jan 2025

Abstract

In this study, L-threonine crystals (L-thr) containing Dy³⁺ ions (L-thrDy5 and L-thrDy10) with varying mass concentrations (5% and 10%) were successfully synthesized using a solvent slow evaporation method. The structural properties were characterized by Powder X-ray diffraction and Rietveld refinement. The data [...] Read more.

In this study, L-threonine crystals (L-thr) containing Dy³⁺ ions (L-thrDy5 and L-thrDy10) with varying mass concentrations (5% and 10%) were successfully synthesized using a solvent slow evaporation method. The structural properties were characterized by Powder X-ray diffraction and Rietveld refinement. The data revealed that all three samples crystallized in orthorhombic symmetry (P2₁2₁2₁-space group) and presented four molecules per unit cell (Z = 4). However, the addition of Dy³⁺ ions induced a dilation effect in the lattice parameters and cell volume of the organic structure. Additionally, the average crystallite size, lattice microstrain, percentage of void centers, and Hirshfeld surface were calculated for the crystals. Thermogravimetric and differential thermal analysis experiments showed that L-thr containing Dy³⁺ ions are thermally stable up to 214 °C. Fourier transform infrared and Raman spectroscopy results indicated that the Dy³⁺ ions interact indirectly with the L-thr molecule via hydrogen bonds, slightly affecting the crystalline structure of the amino acid. Optical analysis in the ultraviolet–visible region displayed eight absorption bands associated with the electronic transitions characteristic of Dy³⁺ ions in samples containing lanthanides. Furthermore, L-thrDy5 and L-thrDy10 crystals, when optically excited at 385 nm, exhibited three photoluminescence bands centered around approximately 554, 575, and 652 nm, corresponding to the ⁴F_7/2 → ⁶H_11/2, ⁴F_9/2 → ⁶H_13/2, and ⁴F_9/2 → ⁶H_11/2 de-excitations. Therefore, this study demonstrated that L-thr crystals containing Dy³⁺ ions are promising candidates for the development of optical materials due to their favorable physical and chemical properties. Additionally, it is noteworthy that the synthesis of these systems is cost-effective, and the synthesis method used is efficient. Full article

(This article belongs to the Section Engineering and Structural Materials)

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9 pages, 1820 KiB

Open AccessArticle

The Movement Mode of the Microworld Particle

by Jinhai Li

Quantum Beam Sci. 2025, 9(1), 2; https://doi.org/10.3390/qubs9010002 - 1 Jan 2025

Abstract

Most physicists are dissatisfied with the current explanation of quantum mechanics, and want to find a method to solve this problem. However, this problem has not been solved perfectly up to now. In this paper, annihilation-generation movement (AGM) is developed according to the [...] Read more.

Most physicists are dissatisfied with the current explanation of quantum mechanics, and want to find a method to solve this problem. However, this problem has not been solved perfectly up to now. In this paper, annihilation-generation movement (AGM) is developed according to the electron motion in hydrogen atoms. To verify the AGM, a curved surface that fits the dark fringe of the single-slit diffraction is proposed. Based on the AGM, the wave function of a free electron is rewritten and the double-slit experiment can be understood. Here, we show that the AGM is an alternative physical image that can be used to solve the puzzles of quantum mechanics, such as Heisenberg’s uncertainty principle and steady-state transition. We anticipate that we can find a new way to explain quantum mechanics based on AGM. Full article

(This article belongs to the Special Issue New Challenges in Electron Beams)

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21 pages, 2161 KiB

Open AccessReview

by Ashraf EL Sherbini, AbdelNasser Aboulfotouh and Tharwat EL Sherbini

Quantum Beam Sci. 2025, 9(1), 1; https://doi.org/10.3390/qubs9010001 - 24 Dec 2024

Abstract

The interaction of pulsed lasers with matter involving nanomaterials as a pure target or thin layer deposited on a target initiates transient plasma, which shows strong enhancement in a spectral line emission. This domain of research has been explored via two well-established techniques [...] Read more.

The interaction of pulsed lasers with matter involving nanomaterials as a pure target or thin layer deposited on a target initiates transient plasma, which shows strong enhancement in a spectral line emission. This domain of research has been explored via two well-established techniques dubbed NELIBS and NELIPS. These Nano-Enhanced Laser-Induced Breakdown or Plasma Spectroscopy techniques entail similarities as well as differences. The newly defined concept of Nano-Enhanced Laser-Induced Plasma Spectroscopy NELIPS is introduced. Thereupon, certain confusion has arisen from various aspects of the similarities as well as differences between the two techniques. In this article, we will investigate the application of either technique to retrieve relevant data about the enhanced spectral line plasma emission phenomenon. To discriminate between these two techniques, a survey on the nature of the target, the origin of enhancement and prevalent theoretical approaches is presented. In this context, the potential achievements, challenges and expected prospects are comparatively highlighted. This review emphasizes the unique contributions of NELIPS, particularly the advanced approach in nanoscale thermal modeling and spectroscopic applications. Full article

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20 pages, 12886 KiB

Open AccessArticle

Microstructural Analysis, Compressive Strength, and Wear Properties of Spark-Plasma-Sintered Al–Mg–PPA Composites

by Osarue Osaruene Edosa, Francis Kunzi Tekweme, Peter A. Olubambi and Kapil Gupta

Quantum Beam Sci. 2024, 8(4), 32; https://doi.org/10.3390/qubs8040032 - 17 Dec 2024

Cited by 2

Abstract

One technique for sintering green compacts and imparting the required qualities to meet the specific application requirements is spark plasma sintering (SPS). This study examines the effects of SPS parameters (sintering temperature and pressure, holding time, and heating rate) and plantain peel ash [...] Read more.

One technique for sintering green compacts and imparting the required qualities to meet the specific application requirements is spark plasma sintering (SPS). This study examines the effects of SPS parameters (sintering temperature and pressure, holding time, and heating rate) and plantain peel ash (PPA) reinforcement concentrations (0, 5 wt%, 10 wt%, 15 wt%, and 20 wt%) on the microstructure, compressive strength, and wear characteristics of the fabricated Al–Mg–PPA composites. As a result of the ball milling machine’s high efficiency, the PPA reinforcement was evenly dispersed throughout the aluminum matrix after 90 min of milling. At lower sintering temperatures and pressures, microstructural flaws such as weak grain boundaries, micro-pores, and micro-cracks were more noticeable than at higher ones. The PPA reinforcement and magnesium powder (wetting agent) increased the composites’ compressive strength by improving the wettability between the PPA reinforcement and the Al matrix. At a weight fraction of 5 wt% PPA, the maximum compressive strength of 432 MPa was attained for the sintered composites, which is a 222% improvement over the sintered aluminum matrix. Additionally, the PPA reinforcement enhanced the wear properties of the sintered Al–Mg–PPA composites by reducing the wear loss. Increasing the wear load resulted in a higher wear rate. The COF for the sintered composites ranges from 0.049 to 0.727. The most consistent correlation between the wear rate and the COF is that as the wear rate decreases, the COF decreases, and vice versa. Abrasive wear was the dominant wear mechanism observed. Tear ridges, shear steps, micro-voids, and cleavages were seen on the composites’ fracture surfaces, an indication of a ductile-brittle fracture. Full article

(This article belongs to the Special Issue Quantum Beam Science: Feature Papers 2024)

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18 pages, 6313 KiB

Open AccessArticle

Exploration of Physical–Chemical and Structural-Phase Mechanisms in Ti-Al Intermetallic Coating Formation

by Almaz Nazarov, Rustem Nagimov, Alexey Oleinik, Alexey Maslov, Alexey Nikolaev, Kamil Ramazanov, Vladimir Denisov, Yuri Ivanov and Elena Korznikova

Quantum Beam Sci. 2024, 8(4), 31; https://doi.org/10.3390/qubs8040031 - 2 Dec 2024

Abstract

This study examines coatings based on Ti-Al system intermetallics deposited in a nitrogen environment. The research investigates the structure, phase composition, chemical composition, and mechanical properties of coatings with varying ratios of Ti-Al to TiAlN layer thicknesses. Multiple analytical techniques, including nanoindentation, sclerometry, [...] Read more.

This study examines coatings based on Ti-Al system intermetallics deposited in a nitrogen environment. The research investigates the structure, phase composition, chemical composition, and mechanical properties of coatings with varying ratios of Ti-Al to TiAlN layer thicknesses. Multiple analytical techniques, including nanoindentation, sclerometry, microhardness measurements, electron microscopy, X-ray diffractometry, and transmission electron microscopy, were employed. The results demonstrate that the coating architecture significantly influences its physical and mechanical properties. Notably, coatings with a variable thickness gradient structure exhibit the best properties and are the most promising for practical applications, offering enhanced hardness, wear resistance, and adhesion strength. Furthermore, the findings indicate that a carefully selected combination of layers can be used to control coating properties across a wide range, making these coatings highly suitable for demanding industrial applications. Full article

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