/library/oar/handle/123456789/2070 2025-11-05T21:15:11Z /library/oar/handle/123456789/140785 Title: Demonstration of full polarization control of soft X-ray pulses with Apple X undulators at SwissFEL using recoil ion momentum spectroscopy Authors: Kittel, Christoph; Sarracini, Antoine; Augustin, Sven; Yang, Ningchen; Al Haddad, Andre; Ferrari, Eugenio; Knopp, Gregor; Knurr, Jonas; Morillo-Candas, Ana Sofia; Swiderska, Iwona; Prat, Eduard; Sammut, Nicholas; Schmidt, Thomas; Bostedt, Christoph; Calvi, Marco; Schnorr, Kirsten Abstract: The ability to freely control the polarization of X-rays enables measurement techniques relying on circular or linear dichroism, which have become indispensable tools for characterizing the properties of chiral molecules or magnetic structures. Therefore, the demand for polarization control in X-ray free-electron lasers is increasing to enable polarization-sensitive dynamical studies on ultrafast time scales. The soft X-ray branch Athos of SwissFEL was designed with the aim of providing freely adjustable and arbitrary polarization by building its undulator solely from modules of the novel Apple X type. In this paper, the magnetic model of the linear inclined and circular Apple X polarization schemes are studied. The polarization is characterized by measuring the angular electron emission distributions of helium for various polarizations using cold target recoil ion momentum spectroscopy. The generation of fully linear polarized light of arbitrary angle, as well as elliptical polarizations of varying degree, are demonstrated. 2024-01-01T00:00:00Z /library/oar/handle/123456789/138445 Title: Advancing prosthesis design : ontology driven multi-disciplinary framework for evolving amputee needs Authors: Patiniott, Nicholas; Borg, Jonathan C.; Farrugia, Philip; Casha, Owen; Gatt, Alfred; Mercieca, Adrian Abstract: To address the evolving life-cycle needs of both the amputee and prosthesis, input from key stakeholder (amputees and family members, prosthetist, physiotherapist, and prosthesis technician) is essential. Collaborative decision-making is necessary for timely involvement in the design, redesign, and maintenance of prostheses. Our framework, adProLiSS, supports this process by integrating stakeholder knowledge and real-time data obtained from smart prosthetic devices. Through an Ontology-Driven Prosthesis-Service System Framework incorporating an Ontology-Driven Consequence Mapping Model, key decision makers can visualise the consequences of their choices, enhancing communication, alignment, and adaptability. This holistic, data-driven approach prioritises patient-centred care, advocating for a paradigm shift in healthcare design practices. 2025-01-01T00:00:00Z /library/oar/handle/123456789/138444 Title: Predicting the behaviour of oscillators using describing functions Authors: Casha, Owen Abstract: This chapter explores the application of describing functions in predicting the behaviour of non-linear oscillators. Describing functions offer an approximate method that simplifies the analysis of complex, non-linear systems by linearising their frequency response characteristics. This chapter delves into the theoretical foundations of describing functions and their practical use in predicting limit cycles in oscillators, highlighting their capacity to estimate the amplitude and the frequency of the oscillations. Through analytical derivations and case studies, this work demonstrates how describing functions bridge the gap between rigorous non-linear analysis and practical engineering approximations. The limitations, accuracy considerations, and alternative techniques are also discussed, providing a comprehensive understanding of when and how to effectively use describing functions in oscillator analysis and design. The discussion is supported by a literature survey on the use of describing functions in oscillator design and analysis and its relevance to automatic amplitude control mechanisms and the minimisation of AM-to-PM noise conversion. 2025-01-01T00:00:00Z /library/oar/handle/123456789/132922 Title: Design of a low-cost resonant electromagnetic scanning mirror and its drive/sense circuitry Authors: Dimech, Nikolai; Grech, Ivan; Farrugia, Russell; Casha, Owen; Micallef, Joseph; Portelli, Barnaby Abstract: This paper presents the novel design and fabrication of a scanning micro-mirror for LiDAR applications, with particular emphasis on its performance, cost-effectiveness, and materials used. Various scanning mirror prototypes, each featuring a scanning mirror plate of 10 mm by 10 mm, were fabricated using different materials: 0.3 mm thick FR4 and polyimide substrates. Different electromagnetic coil structures were evaluated to optimize the scanning performance. The performance attained by each prototype is compared and discussed. The paper also delves into the design of the electromagnetic actuation and sensing circuitry of the mirror. Voltage and current sensing of the actuation coil is implemented with the aim of achieving sensorless positional control. The scanning mirror was designed to have a low resonant frequency in the range of 250 Hz to 550 Hz. An optical angle amplitude of 24.1° was achieved for the micromirror design using the 0.3 mm thick polyimide substrate. 2024-11-01T00:00:00Z