Quantum Beam Science

13 pages, 1699 KiB

Open AccessArticle

Metallic Ca Aggregates Formed Along Ion Tracks and Optical Anisotropy in CaF₂ Crystals Irradiated with Swift Heavy Ions

by Hiroshi Amekura, Norito Ishikawa, Nariaki Okubo, Feng Chen, Kazumasa Narumi, Atsuya Chiba, Yoshimi Hirano, Keisuke Yamada, Shunya Yamamoto and Yuichi Saitoh

Quantum Beam Sci. 2024, 8(4), 29; https://doi.org/10.3390/qubs8040029 - 7 Nov 2024

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Abstract

It is known that swift heavy ion (SHI) irradiation induces the shape elongation of metal nanoparticles (NPs) embedded in transparent insulators, which results in anisotropic optical absorption. Here, we report another type of the optical anisotropy induced in CaF₂ crystals without including intentionally embedded metal NPs. The CaF₂ samples were irradiated with 200 MeV Xe¹⁴⁺ ions with an incident angle of 45° from the surface normal. With the increasing fluence, an absorption band at ~550 nm, which is ascribed to Ca aggregates, increases both the intensity and the anisotropy. XTEM observation clarified the formation of the continuous line structures and the discontinuous NP chains parallel to the SHI beam. Numerical simulations of the optical absorption spectra suggested the NP chains but not the continuous line structures as the origin of the anisotropy. The optical anisotropy in CaF₂ irradiated with SHIs is different from the shape elongation of NPs. Full article

(This article belongs to the Special Issue Modification of Materials by Using Energetic Ion/Electron Beams)

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16 pages, 588 KiB

Open AccessTechnical Note

Optimizing the Automated Analysis of Inorganic Gunshot Residue Particles by SEM-EDX: From Synthetic Particle Standards to More Time-Efficient Settings for Daily Casework

by Zuzanna Brożek-Mucha and Iga Klag

Quantum Beam Sci. 2024, 8(4), 28; https://doi.org/10.3390/qubs8040028 - 6 Nov 2024

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Abstract

Gunshot residues deposited on all surfaces in the nearest vicinity of the shooting incident, when revealed, can contribute to the explanation of various aspects of such an incident for forensic purposes. Examinations of gunshot residue, mainly inorganic particles, at forensic laboratories are expected to be reliable and fast. This primarily depends on the performance of the used scanning electron microscope integrated with an energy dispersive X-ray spectrometer and the automatic program searching for particles of defined characteristics. Among the milestones on the pathway towards quality assurance in examinations of gunshot particles, the invention of the synthetic gunshot residue specimen ought to be named. Such a specimen with particles of known chemical content, size, and location is now used for proficiency testing, which is a condition for a forensic laboratory to obtain accreditation in this subject matter. In this publication, the need for optimization of the procedure for the examination of a synthetic specimen, in alignment with the necessary modifications for real gunshot particles, has been addressed. The presented process of validation resulted in two procedures. The first demonstrates the full capacity of the instrument for detecting all particles present in the synthetic specimen, including the 0.5 micrometer particle at the magnification of 250×. The other procedure is the modification of the first, however aiming at 1-micrometer particles or bigger (at the magnification of 120×) and allowing the necessary backscattered signal threshold changes depending on the actual composition of gunshot residue as well as the abundance of light element debris in the case of real gunshot particles. Full article

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

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17 pages, 4572 KiB

Open AccessArticle

Optical Energy Increasing in a Synchronized Motif-Ring Array of Autonomous Erbium-Doped Fiber Lasers

by José Octavio Esqueda de la Torre, Juan Hugo García-López, Rider Jaimes-Reátegui, José Luis Echenausía-Monroy, Eric Emiliano López-Muñoz, Héctor Eduardo Gilardi-Velázquez and Guillermo Huerta-Cuellar

Quantum Beam Sci. 2024, 8(4), 27; https://doi.org/10.3390/qubs8040027 - 29 Oct 2024

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Abstract

This work investigates the enhancement of optical energy in the synchronized dynamics of three erbium-doped fiber lasers (EDFLs) that are diffusively coupled in a unidirectional ring configuration without the need for external pump modulation. Before the system shows stable high-energy pulses, different dynamic behaviors can be observed in the dynamics of the coupled lasers. The evolution of the studied system was analyzed using different techniques for different values of coupling strength. The system shows the well-known dynamic behavior towards chaos at weak coupling, starting with a fixed point at low coupling and passing through Hopf and torus bifurcations as the coupling strength increases. An interesting finding emerged at high coupling strengths, where phase locking occurs between the frequencies of the three lasers of the system. This phase-locking leads to a significant increase in the peak energy of the EDFL pulses, effectively converting the emission into short, high amplitude pulses. With this method, it is possible to significantly increase the peak energy of the laser compared to a continuous EDFL single pulse. Full article

(This article belongs to the Section High-Power Laser Physics)

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14 pages, 5956 KiB

Open AccessArticle

Development of a Macro X-ray Fluorescence (MA-XRF) Scanner System for In Situ Analysis of Paintings That Operates in a Static or Dynamic Method

by Renato P. de Freitas, Miguel A. de Oliveira, Matheus B. de Oliveira, André R. Pimenta, Valter de S. Felix, Marcelo O. Pereira, Elicardo A. S. Gonçalves, João V. L. Grechi, Fabricio L. e. Silva, Cristiano de S. Carvalho, Jonas G. R. S. Ataliba, Leandro O. Pereira, Lucas C. Muniz, Robson B. dos Santos and Vitor da S. Vital

Quantum Beam Sci. 2024, 8(4), 26; https://doi.org/10.3390/qubs8040026 - 17 Oct 2024

Viewed by 799

Abstract

This work presents the development of a macro X-ray fluorescence (MA-XRF) scanner system for in situ analysis of paintings. The instrument was developed to operate using continuous acquisitions, where the module with the X-ray tube and detector moves at a constant speed, dynamically collecting spectra for each pixel of the artwork. Another possible configuration for the instrument is static acquisitions, where the module with the X-ray tube and detector remains stationary to acquire spectra for each pixel. The work also includes the analytical characterization of the system, which incorporates a 1.00 mm collimator that allows for a resolution of 1.76 mm. Additionally, the study presents the results of the analysis of two Brazilian paintings using this instrument. The elemental maps obtained enabled the characterization of the pigments used in the creation of the artworks and materials used in restoration processes. Full article

(This article belongs to the Special Issue New Advances in Macro X-ray Fluorescence Applications)

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7 pages, 1275 KiB

Open AccessCommunication

Stable and Tunable Erbium Ring Laser by Rayleigh Backscattering Feedback and Saturable Absorber for Single-Mode Operation

by Chien-Yu Liao, Yu-Hsin Kao, Ying-Zhen Chen, Kuan-Ming Cheng, Chun-Yen Lin, Tsu-Hsin Wu, Teng-Yao Yang and Chien-Hung Yeh

Quantum Beam Sci. 2024, 8(4), 25; https://doi.org/10.3390/qubs8040025 - 2 Oct 2024

Viewed by 490

Abstract

This work demonstrates a high-quality erbium-doped fiber (EDF) ring laser in the L-band gain range by combining the Rayleigh backscattering (RB) feedback signal and unpumped EDF induced saturable absorber (SA) filter. The optical filter effect induced by the RB feedback injection and EDF SA could generate single-longitudinal-mode (SLM) behavior and shrink the linewidth to sub-kHz. The output linewidth, power, and optical-signal-to-noise ratio (OSNR) of the fiber ring laser were also shown within the 42 nm wavelength bandwidth of 1565.0 to 1607.0 nm. Also, the instabilities of output power and central wavelength of each lasing lightwave were analyzed with a measurement time of 45 min. Full article

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Quantum Beam Sci., Volume 8, Issue 4 (December 2024) – 5 articles

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