Publications
312 results found
Streeter MJV, Colgan C, Carderelli J, et al., 2024, Narrow bandwidth, low-emittance positron beams from a laser-wakefield accelerator, Scientific Reports, Vol: 14, ISSN: 2045-2322
The rapid progress that plasma wakefield accelerators are experiencing is now posing the question as to whether they could be included in the design of the next generation of high-energy electron-positron colliders. However, the typical structure of the accelerating wakefields presents challenging complications for positron acceleration. Despite seminal proof-of-principle experiments and theoretical proposals, experimental research in plasma-based acceleration of positrons is currently limited by the scarcity of positron beams suitable to seed a plasma accelerator. Here, we report on the first experimental demonstration of a laser-driven source of ultra-relativistic positrons with sufficient spectral and spatial quality to be injected in a plasma accelerator. Our results indicate, in agreement with numerical simulations, selection and transport of positron beamlets containing N e + ≥ 10 5 positrons in a 5% bandwidth around 600 MeV, with femtosecond-scale duration and micron-scale normalised emittance. Particle-in-cell simulations show that positron beams of this kind can be guided and accelerated in a laser-driven plasma accelerator, with favourable scalings to further increase overall charge and energy using PW-scale lasers. The results presented here demonstrate the possibility of performing experimental studies of positron acceleration in a laser-driven wakefield accelerator.
Doherty A, Fourmaux S, Astolfo A, et al., 2023, Femtosecond multimodal imaging with a laser-driven X-ray source, Communications Physics, Vol: 6
Laser-plasma accelerators are compact linear accelerators based on the interaction of high-power lasers with plasma to form accelerating structures up to 1000 times smaller than standard radiofrequency cavities, and they come with an embedded X-ray source, namely betatron source, with unique properties: small source size and femtosecond pulse duration. A still unexplored possibility to exploit the betatron source comes from combining it with imaging methods able to encode multiple information like transmission and phase into a single-shot acquisition approach. In this work, we combine edge illumination-beam tracking (EI-BT) with a betatron X-ray source and present the demonstration of multimodal imaging (transmission, refraction, and scattering) with a compact light source down to the femtosecond timescale. The advantage of EI-BT is that it allows multimodal X-ray imaging technique, granting access to transmission, refraction and scattering signals from standard low-coherence laboratory X-ray sources in a single shot.
Doherty A, Fourmaux S, Astolfo A, et al., 2023, Author Correction: Femtosecond multimodal imaging with a laser-driven X-ray source (Communications Physics, (2023), 6, 1, (288), 10.1038/s42005-023-01412-9), Communications Physics, Vol: 6
Correction to: Communications Physics, published online 11 October 2023. In this article, the author name Wiebe Stolp was incorrectly written as Wiebe Stolpe. The original article has been corrected.
Arran C, Bradford P, Dearling A, et al., 2023, Measurement of Magnetic Cavitation Driven by Heat Flow in a Plasma., Phys Rev Lett, Vol: 131
We describe the direct measurement of the expulsion of a magnetic field from a plasma driven by heat flow. Using a laser to heat a column of gas within an applied magnetic field, we isolate Nernst advection and show how it changes the field over a nanosecond timescale. Reconstruction of the magnetic field map from proton radiographs demonstrates that the field is advected by heat flow in advance of the plasma expansion with a velocity v_{N}=(6±2)×10^{5} m/s. Kinetic and extended magnetohydrodynamic simulations agree well in this regime due to the buildup of a magnetic transport barrier.
Xu N, Streeter MJV, Ettlinger OC, et al., 2023, Versatile tape-drive target for high-repetition-rate laser-driven proton acceleration (vol 11, e23, 2023), HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 11, ISSN: 2095-4719
Chen Y-H, Ting AC, Hafizi B, et al., 2023, Proton acceleration in an overdense hydrogen plasma by intense CO<sub>2</sub> laser pulses with nonlinear propagation effects in the underdense pre-plasma, PHYSICS OF PLASMAS, Vol: 30, ISSN: 1070-664X
Filippi F, Dickson LT, Backhouse M, et al., 2023, Plasma density profile reconstruction of a gas cell for Ionization Induced Laser Wakefield Acceleration, JOURNAL OF INSTRUMENTATION, Vol: 18, ISSN: 1748-0221
Loughran B, Streeter MJV, Ahmed H, et al., 2023, Automated control and optimization of laser-driven ion acceleration, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 11, ISSN: 2095-4719
Xu N, Streeter MJV, Ettlinger OC, et al., 2023, Versatile tape-drive target for high-repetition-rate laser-driven proton acceleration, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 11, ISSN: 2095-4719
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- Citations: 2
Dover NP, Ziegler T, Assenbaum S, et al., 2023, Enhanced ion acceleration from transparency-driven foils demonstrated at two ultraintense laser facilities, Light: Science & Applications, Vol: 12, ISSN: 2095-5545
Laser-driven ion sources are a rapidly developing technology producing high energy, high peak current beams. Their suitability for applications, such as compact medical accelerators, motivates development of robust acceleration schemes using widely available repetitive ultraintense femtosecond lasers. These applications not only require high beam energy, but also place demanding requirements on the source stability and controllability. This can be seriously affected by the laser temporal contrast, precluding the replication of ion acceleration performance on independent laser systems with otherwise similar parameters. Here, we present the experimental generation of >60 MeV protons and >30 MeV u-1 carbon ions from sub-micrometre thickness Formvar foils irradiated with laser intensities >1021 Wcm2. Ions are accelerated by an extreme localised space charge field ≳30 TVm-1, over a million times higher than used in conventional accelerators. The field is formed by a rapid expulsion of electrons from the target bulk due to relativistically induced transparency, in which relativistic corrections to the refractive index enables laser transmission through normally opaque plasma. We replicate the mechanism on two different laser facilities and show that the optimum target thickness decreases with improved laser contrast due to reduced pre-expansion. Our demonstration that energetic ions can be accelerated by this mechanism at different contrast levels relaxes laser requirements and indicates interaction parameters for realising application-specific beam delivery.
Streeter MJV, Colgan C, Cobo CC, et al., 2023, Laser wakefield accelerator modelling with variational neural networks, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 11, ISSN: 2095-4719
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- Citations: 1
Streeter MJV, Ma Y, Kettle B, et al., 2022, Characterization of laser wakefield acceleration efficiency with octave spanning near-IR spectrum measurements, PHYSICAL REVIEW ACCELERATORS AND BEAMS, Vol: 25
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- Citations: 1
Dickson LT, Underwood CID, Filippi F, et al., 2022, Mechanisms to control laser-plasma coupling in laser wakefield electron acceleration, Physical Review Accelerators and Beams, Vol: 25, Pages: 1-12, ISSN: 2469-9888
Experimental results, supported by precise modeling, demonstrate optimization of a plasma-based injector with intermediate laser pulse energy (<1 J), corresponding to a normalized vector potential a0=2.15, using ionization injection in a tailored plasma density profile. An increase in electron bunch quality and energy is achieved experimentally with the extension of the density downramp at the plasma exit. Optimization of the focal position of the laser pulse in the tailored plasma density profile is shown to efficiently reduce electron bunch angular deviation, leading to a better alignment of the electron bunch with the laser axis. Single peak electron spectra are produced in a previously unexplored regime by combining an early focal position and adaptive optic control of the laser wavefront by optimizing the symmetry of the prefocal laser energy distribution. Experimental results have been validated through particle-in-cell simulations using realistic laser energy, phase distribution, and temporal envelope, allowing for accurate predictions of difficult to model parameters, such as total charge and spatial properties of the electron bunches, opening the way for more accurate modeling for the design of plasma-based accelerators.
Alejo A, Ahmed H, Krygier AG, et al., 2022, Stabilized Radiation Pressure Acceleration and Neutron Generation in Ultrathin Deuterated Foils, PHYSICAL REVIEW LETTERS, Vol: 129, ISSN: 0031-9007
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- Citations: 2
Martin P, Ahmed H, Doria D, et al., 2022, Absolute calibration of Fujifilm BAS-TR image plate response to laser driven protons up to 40 MeV, REVIEW OF SCIENTIFIC INSTRUMENTS, Vol: 93, ISSN: 0034-6748
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- Citations: 1
Maitrallain A, Brunetti E, Streeter MJ, et al., 2022, Parametric study of high-energy ring-shaped electron beams from a laser wakefield accelerator, NEW JOURNAL OF PHYSICS, Vol: 24, ISSN: 1367-2630
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- Citations: 3
McIlvenny A, Doria D, Romagnani L, et al., 2021, Selective Ion Acceleration by Intense Radiation Pressure, PHYSICAL REVIEW LETTERS, Vol: 127, ISSN: 0031-9007
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- Citations: 16
Finlay OJ, Gruse JN, Thornton C, et al., 2021, Characterisation of a laser plasma betatron source for high resolution x-ray imaging, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 63, ISSN: 0741-3335
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- Citations: 1
Danson CN, White M, Barr JRM, et al., 2021, A history of high-power laser research and development in the United Kingdom, High Power Laser Science and Engineering, Vol: 9, Pages: 1-86, ISSN: 2095-4719
The first demonstration of laser action in ruby was made in 1960 by T. H. Maiman of Hughes Research Laboratories, USA. Many laboratories worldwide began the search for lasers using different materials, operating at different wavelengths. In the UK, academia, industry and the central laboratories took up the challenge from the earliest days to develop these systems for a broad range of applications. This historical review looks at the contribution the UK has made to the advancement of the technology, the development of systems and components and their exploitation over the last 60 years.
Assmann RW, Weikum MK, Akhter T, et al., 2021, Erratum to: EuPRAXIA Conceptual Design Report, European Physical Journal: Special Topics, Vol: 229, Pages: 11-31, ISSN: 1951-6355
Gruse J-N, Streeter MJV, Thornton C, et al., 2020, Application of compact laser-driven accelerator X-ray sources for industrial imaging, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors, and Associated Equipment, Vol: 983, Pages: 1-7, ISSN: 0168-9002
X-rays generated by betatron oscillations of electrons in a laser-driven plasma accelerator were charac-terised and applied to imaging industrial samples. With a125TWlaser, a low divergence beam with5.2 ± 1.7 × 107photonsmrad−2per pulse was produced with a synchrotron spectrum with a critical energy of14.6 ± 1.3keV. Radiographs were obtained of a metrology test sample, battery electrodes, and a damage sitein a composite material. These results demonstrate the suitability of the source for non-destructive evaluationapplications. The potential for industrial implementation of plasma accelerators is discussed.
Streeter M, Najmudin Z, Shalloo R, et al., 2020, Automation and control of laser wakefield accelerators using Bayesian optimisation, Nature Communications, Vol: 11, Pages: 1-8, ISSN: 2041-1723
Laser wakefield accelerators promise to revolutionize many areas of accelerator science. However, one of the greatest challenges to their widespread adoption is the difficulty in control and optimization of the accelerator outputs due to coupling between input parameters and the dynamic evolution of the accelerating structure. Here, we use machine learning techniques to automate a 100 MeV-scale accelerator, which optimized its outputs by simultaneously varying up to six parameters including the spectral and spatial phase of the laser and the plasma density and length. Most notably, the model built by the algorithm enabled optimization of the laser evolution that might otherwise have been missed in single-variable scans. Subtle tuning of the laser pulse shape caused an 80% increase in electron beam charge, despite the pulse length changing by just 1%.
Assmann RW, Weikum MK, Akhter T, et al., 2020, EuPRAXIA conceptual design report, European Physical Journal: Special Topics, Vol: 229, Pages: 3675-4284, ISSN: 1951-6355
This report presents the conceptual design of a new European research infrastructure EuPRAXIA. The concept has been established over the last four years in a unique collaboration of 41 laboratories within a Horizon 2020 design study funded by the European Union. EuPRAXIA is the first European project that develops a dedicated particle accelerator research infrastructure based on novel plasma acceleration concepts and laser technology. It focuses on the development of electron accelerators and underlying technologies, their user communities, and the exploitation of existing accelerator infrastructures in Europe. EuPRAXIA has involved, amongst others, the international laser community and industry to build links and bridges with accelerator science — through realising synergies, identifying disruptive ideas, innovating, and fostering knowledge exchange. The Eu-PRAXIA project aims at the construction of an innovative electron accelerator using laser- and electron-beam-driven plasma wakefield acceleration that offers a significant reduction in size and possible savings in cost over current state-of-the-art radiofrequency-based accelerators. The foreseen electron energy range of one to five gigaelectronvolts (GeV) and its performance goals will enable versatile applications in various domains, e.g. as a compact free-electron laser (FEL), compact sources for medical imaging and positron generation, table-top test beams for particle detectors, as well as deeply penetrating X-ray and gamma-ray sources for material testing. EuPRAXIA is designed to be the required stepping stone to possible future plasma-based facilities, such as linear colliders at the high-energy physics (HEP) energy frontier. Consistent with a high-confidence approach, the project includes measures to retire risk by establishing scaled technology demonstrators. This report includes preliminary models for project implementation, cost and schedule that would allow operation of the full Eu-PRAXIA facili
Underwood CID, Baird CD, Murphy CD, et al., 2020, Development of control mechanisms for a laser wakefield accelerator-driven bremsstrahlung x-ray source for advanced radiographic imaging, PLASMA PHYSICS AND CONTROLLED FUSION, Vol: 62, ISSN: 0741-3335
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- Citations: 9
Dover NP, Nishiuchi M, Sakaki H, et al., 2020, Demonstration of repetitive energetic proton generation by ultra-intense laser interaction with a tape target, High Energy Density Physics, Vol: 37, Pages: 100847-100847, ISSN: 1574-1818
Kondo K, Nishiuchi M, Sakaki H, et al., 2020, High-intensity laser-driven oxygen source from CW laser-heated titanium tape targets, Crystals, Vol: 10, Pages: 837-837, ISSN: 2073-4352
The interaction of high-intensity laser pulses with solid targets can be used as a highly charged, energetic heavy ion source. Normally, intrinsic contaminants on the target surface suppress the performance of heavy ion acceleration from a high-intensity laser–target interaction, resulting in preferential proton acceleration. Here, we demonstrate that CW laser heating of 5 µm titanium tape targets can remove contaminant hydrocarbons in order to expose a thin oxide layer on the metal surface, ideal for the generation of energetic oxygen beams. This is demonstrated by irradiating the heated targets with a PW class high-power laser at an intensity of 5 × 1021 W/cm2, showing enhanced acceleration of oxygen ions with a non-thermal-like distribution. Our new scheme using a CW laser-heated Ti tape target is promising for use as a moderate repetition energetic oxygen ion source for future applications.
Xu ZY, Xiao CF, Lu HY, et al., 2020, New injection and acceleration scheme of positrons in the laser-plasma bubble regime, PHYSICAL REVIEW ACCELERATORS AND BEAMS, Vol: 23, ISSN: 2469-9888
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- Citations: 8
Aymar G, Becker T, Boogert S, et al., 2020, LhARA: The Laser-hybrid accelerator for radiobiological applications, Frontiers in Physics, Vol: 8, Pages: 1-21, ISSN: 2296-424X
The “Laser-hybrid Accelerator for Radiobiological Applications,” LhARA, is conceived as a novel, flexible facility dedicated to the study of radiobiology. The technologies demonstrated in LhARA, which have wide application, will be developed to allow particle-beam therapy to be delivered in a new regimen, combining a variety of ion species in a single treatment fraction and exploiting ultra-high dose rates. LhARA will be a hybrid accelerator system in which laser interactions drive the creation of a large flux of protons or light ions that are captured using a plasma (Gabor) lens and formed into a beam. The laser-driven source allows protons and ions to be captured at energies significantly above those that pertain in conventional facilities, thus evading the current space-charge limit on the instantaneous dose rate that can be delivered. The laser-hybrid approach, therefore, will allow the radiobiology that determines the response of tissue to ionizing radiation to be studied with protons and light ions using a wide variety of time structures, spectral distributions, and spatial configurations at instantaneous dose rates up to and significantly beyond the ultra-high dose-rate “FLASH” regime. It is proposed that LhARA be developed in two stages. In the first stage, a programme of in vitro radiobiology will be served with proton beams with energies between 10 and 15 MeV. In stage two, the beam will be accelerated using a fixed-field alternating-gradient accelerator (FFA). This will allow experiments to be carried out in vitro and in vivo with proton beam energies of up to 127 MeV. In addition, ion beams with energies up to 33.4 MeV per nucleon will be available for in vitro and in vivo experiments. This paper presents the conceptual design for LhARA and the R&D programme by which the LhARA consortium seeks to establish the facility.
Nishiuchi M, Dover NP, Hata M, et al., 2020, Dynamics of laser-driven heavy-ion acceleration clarified by ion charge states, Physical Review Research, Vol: 2, Pages: 033081 – 1-033081 – 13, ISSN: 2643-1564
Motivated by the development of next-generation heavy-ion sources, we have investigated the ionization and acceleration dynamics of an ultraintense laser-driven high-Z silver target, experimentally, numerically, and analytically. Using a novel ion measurement technique allowing us to uniquely identify silver ions, we experimentally demonstrate generation of highly charged silver ions (Z∗=45+2−2) with energies of >20 MeV/nucleon (>2.2 GeV) from submicron silver targets driven by a laser with intensity 5×1021W/cm2, with increasing ion energy and charge state for decreasing target thickness. We show that although target pre-expansion by the unavoidable rising edge of state-of-the-art high-power lasers can limit proton energies, it is advantageous for heavy-ion acceleration. Two-dimensional particle-in-cell simulations show that the Joule heating in the target bulk results in a high temperature (∼10keV) solid density plasma, leading to the generation of high flux highly charged ions (Z∗=40+2−2, ≳10MeV/nucleon) via electron collisional ionization, which are extracted and accelerated with a small divergence by an extreme sheath field at the target rear. However, with reduced target thickness this favorable acceleration is degraded due to the target deformation via laser hole boring, which accompanies higher energy ions with higher charge states but in an uncontrollable manner. Our elucidation of the fundamental processes of high-intensity laser-driven ionization and ion acceleration provides a path for improving the control and parameters of laser-driven heavy-ion sources, a key component for next-generation heavy-ion accelerators.
Streeter MJV, Najmudin Z, 2020, Compton recoil effects in staging of laser wakefield accelerators, PHYSICAL REVIEW ACCELERATORS AND BEAMS, Vol: 23, ISSN: 2469-9888
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- Citations: 1
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