1. |
- Verra, L., et al.
(author)
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Controlled Growth of the Self-Modulation of a Relativistic Proton Bunch in Plasma
- 2022
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In: Physical Review Accelerators and Beams. - : American Physical Society. - 2469-9888. ; 25:7
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Journal article (peer-reviewed)abstract
- A long, narrow, relativistic charged particle bunch propagating in plasma is subject to the self -modulation (SM) instability. We show that SM of a proton bunch can be seeded by the wakefields driven by a preceding electron bunch. SM timing reproducibility and control are at the level of a small fraction of the modulation period. With this seeding method, we independently control the amplitude of the seed wakefields with the charge of the electron bunch and the growth rate of SM with the charge of the proton bunch. Seeding leads to larger growth of the wakefields than in the instability case.
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2. |
- Verra, L., et al.
(author)
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Development of the self-modulation instability of a relativistic proton bunch in plasma
- 2023
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In: Physics of Plasmas. - : American Institute of Physics (AIP). - 1070-664X .- 1089-7674. ; 30:8
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Journal article (peer-reviewed)abstract
- Self-modulation is a beam-plasma instability that is useful to drive large-amplitude wakefields with bunches much longer than the plasma skin depth. We present experimental results showing that, when increasing the ratio between the initial transverse size of the bunch and the plasma skin depth, the instability occurs later along the bunch, or not at all, over a fixed plasma length because the amplitude of the initial wakefields decreases. We show cases for which self-modulation does not develop, and we introduce a simple model discussing the conditions for which it would not occur after any plasma length. Changing bunch size and plasma electron density also changes the growth rate of the instability. We discuss the impact of these results on the design of a particle accelerator based on the self-modulation instability seeded by a relativistic ionization front, such as the future upgrade of the Advanced WAKefield Experiment.
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3. |
- Verra, L., et al.
(author)
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Filamentation of a relativistic proton bunch in plasma
- 2024
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In: Physical review. E. - : American Physical Society. - 2470-0045 .- 2470-0053. ; 109:5
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Journal article (peer-reviewed)abstract
- We show in experiments that a long, underdense, relativistic proton bunch propagating in plasma undergoes the oblique instability, which we observe as filamentation. We determine a threshold value for the ratio between the bunch transverse size and plasma skin depth for the instability to occur. At the threshold, the outcome of the experiment alternates between filamentation and self-modulation instability (evidenced by longitudinal modulation into microbunches). Time-resolved images of the bunch density distribution reveal that filamentation grows to an observable level late along the bunch, confirming the spatiotemporal nature of the instability. We provide a rough estimate of the amplitude of the magnetic field generated in the plasma by the instability and show that the associated magnetic energy increases with plasma density.
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4. |
- Nechaeva, T., et al.
(author)
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Hosing of a Long Relativistic Particle Bunch in Plasma
- 2024
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In: Physical Review Letters. - : American Physical Society. - 0031-9007 .- 1079-7114. ; 132:7
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Journal article (peer-reviewed)abstract
- Experimental results show that hosing of a long particle bunch in plasma can be induced by wakefields driven by a short, misaligned preceding bunch. Hosing develops in the plane of misalignment, selfmodulation in the perpendicular plane, at frequencies close to the plasma electron frequency, and are reproducible. Development of hosing depends on misalignment direction, its growth on misalignment extent and on proton bunch charge. Results have the main characteristics of a theoretical model, are relevant to other plasma -based accelerators and represent the first characterization of hosing.
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5. |
- Champendal, M., et al.
(author)
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A scoping review of person-centred care strategies used in diagnostic Nuclear Medicine
- 2024
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In: Radiography. - : Elsevier. - 1078-8174 .- 1532-2831. ; 30:2, s. 448-456
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Research review (peer-reviewed)abstract
- IntroductionPerson-centred care (PCC) emphasises the need for the health care professional to prioritise individual patient needs, thereby fostering a collaborative and emphatic environment that empowers patients to actively participate in their own care. This article will explore the purpose of PCC in Nuclear Medicine (NM), while discussing strategies that may be used to implement PCC during diagnostic NM examinations performed on adult patients.MethodsThe scoping review was conducted in accordance with the Joanna Briggs Institute methodology. The search was performed on PubMed, Embase and Cinhal in June 2023 and included studies in English, Spanish, Portuguese and Italian. The research equation combined keywords and Medical Subject Heading terms (MeSH) related to person-centred care (PCC), for all types of nuclear medicine diagnostic examinations performed. Three independent review authors screened all abstracts and titles, and all eligible full-text publications were included in this scoping review.ResultsFifty-three articles, published between 1993 and 2022, met the inclusion criteria for this scoping review. Seven articles were published in 2015 while 56.6 % of all included studies were performed in Europe. Most studies (n = 39/53) focused on the patients only, with the identified patient benefits being: improve patient experience (67.9 %), increase patient comfort (13.2 %), increase patient knowledge (5.7 %), reduction of patient anxiety (9.4 %) and reduction of waiting/scan time (3.8 %).ConclusionThe scoping review identified a lack of research investigating the use of person-centred care strategies in NM. Future research will focus on using an international survey to explore this topic in nuclear medicine departments overseas.Implications for practiceBy applying PCC principles, the NM professional can improve the patient care pathway and increase patient satisfaction, leading to enhanced clinical outcomes.
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