Imperial College London

ProfessorZulfikarNajmudin

Faculty of Natural SciencesDepartment of Physics

Professor of Physics
 
 
 
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Contact

 

z.najmudin Website

 
 
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Location

 

736Blackett LaboratorySouth Kensington Campus

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Summary

 

Publications

Publication Type
Year
to

296 results found

McIlvenny A, Doria D, Romagnani L, Ahmed H, Booth N, Ditter EJ, Ettlinger OC, Hicks GS, Martin P, Scott GG, Williamson SDR, Macchi A, McKenna P, Najmudin Z, Neely D, Kar S, Borghesi Met al., 2021, Selective Ion Acceleration by Intense Radiation Pressure, PHYSICAL REVIEW LETTERS, Vol: 127, ISSN: 0031-9007

Journal article

Finlay OJ, Gruse JN, Thornton C, Allott R, Armstrong CD, Baird CD, Bourgeois N, Brenner C, Cipiccia S, Cole JM, Gregory C, Jamison S, Katzir Y, Lopes NC, Mangles SPD, Murphy CD, Najmudin Z, Neely D, Pickard LR, Potter KD, Rajeev PP, Rusby D, Selwood MP, Symes DR, Underwood CID, Wood JC, Thomas AGR, Streeter MJet 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

Journal article

Danson CN, White M, Barr JRM, Bett T, Blyth P, Bowley D, Brenner C, Collins RJ, Croxford N, Dangor AEB, Devereux L, Dyer PE, Dymoke-Bradshaw A, Edwards CB, Ewart P, Ferguson AI, Girkin JM, Hall DR, Hanna DC, Harris W, Hillier DI, Hooker CJ, Hooker SM, Hopps N, Hull J, Hunt D, Jaroszynski DA, Kempenaars M, Kessler H, Knight PL, Knight S, Knowles A, Lewis CLS, Lipton KS, Littlechild A, Littlechild J, Maggs P, Malcolm GPA, Mangles SPD, Martin W, McKenna P, Moore RO, Morrison C, Najmudin Z, Neely D, New GHC, Norman MJ, Paine T, Parker AW, Penman RR, Pert GJ, Pietraszewski C, Randewich A, Rizvi NH, Seddon N, Sheng Z-M, Slater D, Smith RA, Spindloe C, Taylor R, Thomas G, Tisch JWG, Wark JS, Webb C, Wiggins SM, Willford D, Winstone Tet 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.

Journal article

Assmann RW, Weikum MK, Akhter T, Alesini D, Alexandrova AS, Anania MP, Andreev NE, Andriyash I, Artioli M, Aschikhin A, Audet T, Bacci A, Barna IF, Bartocci S, Bayramian A, Beaton A, Beck A, Bellaveglia M, Beluze A, Bernhard A, Biagioni A, Bielawski S, Bisesto FG, Bonatto A, Boulton L, Brandi F, Brinkmann R, Briquez F, Brottier F, Bruendermann E, Buescher M, Buonomo B, Bussmann MH, Bussolino G, Campana P, Cantarella S, Cassou K, Chance A, Chen M, Chiadroni E, Cianchi A, Cioeta F, Clarke JA, Cole JM, Costa G, Couprie M-E, Cowley J, Croia M, Cros B, Crump PA, D'Arcy R, Dattoli G, Del Dotto A, Delerue N, Del Franco M, Delinikolas P, De Nicola S, Dias JM, Di Giovenale D, Diomede M, Di Pasquale E, Di Pirro G, Di Raddo G, Dorda U, Erlandson AC, Ertel K, Esposito A, Falcoz F, Falone A, Fedele R, Ferran Pousa A, Ferrario M, Filippi F, Fils J, Fiore G, Fiorito R, Fonseca RA, Franzini G, Galimberti M, Gallo A, Galvin TC, Ghaith A, Ghigo A, Giove D, Giribono A, Gizzi LA, Gruener FJ, Habib AF, Haefner C, Heinemann T, Helm A, Hidding B, Holzer BJ, Hooker SM, Hosokai T, Huebner M, Ibison M, Incremona S, Irman A, Iungo F, Jafarinia FJ, Jakobsson O, Jaroszynski DA, Jaster-Merz S, Joshi C, Kaluza M, Kando M, Karger OS, Karsch S, Khazanov E, Khikhlukha D, Kirchen M, Kirwan G, Kitegi C, Knetsch A, Kocon D, Koester P, Kononenko OS, Korn G, Kostyukov I, Kruchinin KO, Labate L, Le Blanc C, Lechner C, Lee P, Leemans W, Lehrach A, Li X, Li Y, Libov V, Lifschitz A, Lindstrom CA, Litvinenko V, Lu W, Lundh O, Maier AR, Malka V, Manahan GG, Mangles SPD, Marcelli A, Marchetti B, Marcouille O, Marocchino A, Marteau F, Martinez de la Ossa A, Martins JL, Mason PD, Massimo F, Mathieu F, Maynard G, Mazzotta Z, Mironov S, Molodozhentsev AY, Morante S, Mosnier A, Mostacci A, Mueller A-S, Murphy CD, Najmudin Z, Nghiem PAP, Nguyen F, Niknejadi P, Nutter A, Osterhoff J, Oumbarek Espinos D, Paillard J-L, Papadopoulos DN, Patrizi B, Pattathil R, Pellegrino L, Petralia A, Petrillo V, Piersanti L, Pocsai MAet al., 2021, Erratum to: EuPRAXIA Conceptual Design Report, European Physical Journal: Special Topics, Vol: 229, Pages: 11-31, ISSN: 1951-6355

Journal article

Gruse J-N, Streeter MJV, Thornton C, Armstrong CD, Baird CD, Bourgeois N, Cipiccia S, Finlay OJ, Gregory CD, Katzir Y, Lopes NC, Mangles SPD, Najmudin Z, Neely D, Pickard LR, Potter KD, Rajeev PP, Rusby DR, Underwood CID, Warnett JM, Williams MA, Wood JC, Murphy CD, Brenner CM, Symes DRet 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.

Journal article

Streeter M, Najmudin Z, Shalloo R, Gruse J-Net 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%.

Journal article

Underwood CID, Baird CD, Murphy CD, Armstrong CD, Thornton C, Finlay OJ, Streeter MJ, Selwood MP, Brierley N, Cipiccia S, Gruse J-N, McKenna P, Najmudin Z, Neely D, Rusby D, Symes DR, Brenner CMet 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

Journal article

Assmann RW, Weikum MK, Akhter T, Alesini D, Alexandrova AS, Anania MP, Andreev NE, Andriyash I, Artioli M, Aschikhin A, Audet T, Bacci A, Barna IF, Bartocci S, Bayramian A, Beaton A, Beck A, Bellaveglia M, Beluze A, Bernhard A, Biagioni A, Bielawski S, Bisesto FG, Bonatto A, Boulton L, Brandi F, Brinkmann R, Briquez F, Brottier F, Brundermann E, Buscher M, Buonomo B, Bussmann MH, Bussolino G, Campana P, Cantarella S, Cassou K, Chance A, Chen M, Chiadroni E, Cianchi A, Cioeta F, Clarke JA, Cole JM, Costa G, Couprie M-E, Cowley J, Croia M, Cros B, Crump PA, D'Arcy R, Dattoli G, Del Dotto A, Delerue N, Del Franco M, Delinikolas P, De Nicola S, Dias JM, Di Giovenale D, Diomede M, Di Pasquale E, Di Pirro G, Di Raddo G, Dorda U, Erlandson AC, Ertel K, Esposito A, Falcoz F, Falone A, Fedele R, Ferran Pousa A, Ferrario M, Filippi F, Fils J, Fiore G, Fiorito R, Fonseca RA, Franzini G, Galimberti M, Gallo A, Galvin TC, Ghaith A, Ghigo A, Giove D, Giribono A, Gizzi LA, Gruener FJ, Habib AF, Haefner C, Heinemann T, Helm A, Hidding B, Holzer BJ, Hooker SM, Hosokai T, Huebner M, Ibison M, Incremona S, Irman A, Iungo F, Jafarinia FJ, Jakobsson O, Jaroszynski DA, Jaster-Merz S, Joshi C, Kaluza M, Kando M, Karger OS, Karsch S, Khazanov E, Khikhlukha D, Kirchen M, Kirwan G, Kitegi C, Knetsch A, Kocon D, Koester P, Kononenko OS, Korn G, Kostyukov I, Kruchinin KO, Labate L, Le Blanc C, Lechner C, Lee P, Leemans W, Lehrach A, Li X, Li Y, Libov V, Lifschitz A, Lindstrom CA, Litvinenko V, Lu W, Lundh O, Maier AR, Malka V, Manahan GG, Mangles SPD, Marcelli A, Marchetti B, Marcouille O, Marocchino A, Marteau F, Martinez de la Ossa A, Martins JL, Mason PD, Massimo F, Mathieu F, Maynard G, Mazzotta Z, Mironov S, Molodozhentsev AY, Morante S, Mosnier A, Mostacci A, Mueller A-S, Murphy CD, Najmudin Z, Nghiem PAP, Nguyen F, Niknejadi P, Nutter A, Osterhoff J, Oumbarek Espinos D, Paillard J-L, Papadopoulos DN, Patrizi B, Pattathil R, Pellegrino L, Petralia A, Petrillo V, Piersanti L, Pocsai MA Pet 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

Journal article

Dover NP, Nishiuchi M, Sakaki H, Kondo K, Lowe HF, Alkhimova MA, Ditter EJ, Ettlinger OC, Faenov AY, Hata M, Hicks GS, Iwata N, Kiriyama H, Koga JK, Miyahara T, Najmudin Z, Pikuz TA, Pirozhkov AS, Sagisaka A, Schramm U, Sentoku Y, Watanabe Y, Ziegler T, Zeil K, Kando M, Kondo Ket 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

Journal article

Kondo K, Nishiuchi M, Sakaki H, Dover NP, Lowe HF, Miyahara T, Watanabe Y, Ziegler T, Zeil K, Schramm U, Ditter EJ, Hicks GS, Ettlinger OC, Najmudin Z, Kiriyama H, Kando M, Kondo Ket 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.

Journal article

Xu ZY, Xiao CF, Lu HY, Hu RH, Yu JQ, Gong Z, Shou YR, Liu JX, Xie CZ, Chen SY, Lu HG, Xu TQ, Li RX, Hafz N, Li S, Najmudin Z, Rajeev PP, Neely D, Yan XQet 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

Journal article

Aymar G, Becker T, Boogert S, Borghesi M, Bingham R, Brenner C, Burrows PN, Ettlinger OC, Dascalu T, Gibson S, Greenshaw T, Gruber S, Gujral D, Hardiman C, Hughes J, Jones WG, Kirkby K, Kurup A, Lagrange J-B, Long K, Luk W, Matheson J, McKenna P, McLauchlan R, Najmudin Z, Lau HT, Parsons JL, Pasternak J, Pozimski J, Prise K, Puchalska M, Ratoff P, Schettino G, Shields W, Smith S, Thomason J, Towe S, Weightman P, Whyte C, Xiao Ret 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.

Journal article

Nishiuchi M, Dover NP, Hata M, Sakaki H, Kondo K, Lowe HF, Miyahara T, Kiriyama H, Koga JK, Iwata N, Alkhimova MA, Pirozhkov AS, Faenov AY, Pikuz TA, Sagisaka A, Watanabe Y, Kando M, Kondo K, Ditter EJ, Ettlinger OC, Hicks GS, Najmudin Z, Ziegler T, Zeil K, Schramm U, Sentoku Yet 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.

Journal article

Streeter MJV, Najmudin Z, 2020, Compton recoil effects in staging of laser wakefield accelerators, PHYSICAL REVIEW ACCELERATORS AND BEAMS, Vol: 23, ISSN: 2469-9888

Journal article

Mangles S, 2020, Bright x-ray radiation from plasma bubbles in an evolving laser wakefield accelerator, Physical Review Accelerators and Beams, Vol: 23, Pages: 061301 – 1-061301 – 6, ISSN: 2469-9888

We show that the properties of the electron beam and bright x rays produced by a laser wakefield accelerator can be predicted if the distance over which the laser self-focuses and compresses prior to self-injection is taken into account. A model based on oscillations of the beam inside a plasma bubble shows that performance is optimized when the plasma length is matched to the laser depletion length. With a 200 TW laser pulse, this results in an x-ray beam with a median photon energy of 20 keV, >6×108  photons above 1 keV per shot, and a peak brightness of 3×1022  photons s−1 mrad−2 mm−2 (0.1%  BW)−1.

Journal article

Bloom MS, Streeter MJV, Kneip S, Bendoyro RA, Cheklov O, Cole JM, Doepp A, Hooker CJ, Holloway J, Jiang J, Lopes NC, Nakamura H, Norreys PA, Rajeev PP, Symes DR, Schreiber J, Wood JC, Wing M, Najmudin Z, Mangles SPDet al., 2020, Bright X-ray radiation from plasma bubbles in an evolving laser wakefield accelerator

We show that the properties of the electron beam and bright X-rays producedby a laser wakefield accelerator can be predicted if the distance over whichthe laser self-focuses and compresses prior to self-injection is taken intoaccount. A model based on oscillations of the beam inside a plasma bubble showsthat performance is optimised when the plasma length is matched to the laserdepletion length. With a 200~TW laser pulse this results in an X-ray beam withmedian photon energy of 20 keV, $> 10^{9}$ photons per shot and a peakbrightness of $4 \times 10^{23}$ photons s$^{-1}$ mrad$^{-2}$ mm$^{-2}$ (0.1 %BW)$^{-1}$.

Working paper

Hussein AE, Senabulya N, Ma Y, Streeter MJV, Kettle B, Dann SJD, Albert F, Bourgeois N, Cipiccia S, Cole JM, Finlay O, Gerstmayr E, González IG, Higginbotham A, Jaroszynski DA, Falk K, Krushelnick K, Lemos N, Lopes NC, Lumsdon C, Lundh O, Mangles SPD, Najmudin Z, Rajeev PP, Schlepütz CM, Shahzad M, Smid M, Spesyvtsev R, Symes DR, Vieux G, Willingale L, Wood JC, Shahani AJ, Thomas AGRet al., 2020, Author Correction: Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures, Scientific Reports, Vol: 10, ISSN: 2045-2322

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

Journal article

Passalidis S, Ettlinger OC, Hicks GS, Dover NP, Najmudin Z, Benis EP, Kaselouris E, Papadogiannis NA, Tatarakis M, Dimitriou Vet al., 2020, Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 8, ISSN: 2095-4719

Journal article

Kurup A, Pasternak J, Taylor R, Murgatroyd L, Ettlinger O, Shields W, Nevay L, Gruber S, Pozimski J, Lau HT, Long K, Blackmore V, Barber G, Najmudin Z, Yarnold Jet al., 2019, Simulation of a radiobiology facility for the Centre for the Clinical Application of Particles, Physica Medica, Vol: 65, Pages: 21-28, ISSN: 1120-1797

The Centre for the Clinical Application of Particles’ Laser-hybrid Accelerator for Radiobiological Applications (LhARA) facility is being studied and requires simulation of novel accelerator components (such as the Gabor lens capture system), detector simulation and simulation of the ion beam interaction with cells. The first stage of LhARA will provide protons up to 15 MeV for in vitro studies. The second stage of LhARA will use a fixed-field accelerator to increase the energy of the particles to allow in vivo studies with protons and in vitro studies with heavier ions.BDSIM, a Geant4 based accelerator simulation tool, has been used to perform particle tracking simulations to verify the beam optics design done by BeamOptics and these show good agreement. Design parameters were defined based on an EPOCH simulation of the laser source and a series of mono-energetic input beams were generated from this by BDSIM. The tracking results show the large angular spread of the input beam (0.2 rad) can be transported with a transmission of almost 100% whilst keeping divergence at the end station very low (<0.1 mrad). The legacy of LhARA will be the demonstration of technologies that could drive a step-change in the provision of proton and light ion therapy (i.e. a laser source coupled to a Gabor lens capture and a fixed-field accelerator), and a system capable of delivering a comprehensive set of experimental data that can be used to enhance the clinical application of proton and light ion therapy.

Journal article

Consoli F, De Angelis R, Robinson TS, Giltrap S, Hicks GS, Ditter EJ, Ettlinger OC, Najmudin Z, Notley M, Smith RAet al., 2019, Generation of intense quasi-electrostatic fields due to deposition of particles accelerated by petawatt-range laser-matter interactions, Scientific Reports, Vol: 9, ISSN: 2045-2322

We demonstrate here for the first time that charge emitted by laser-target interactions at petawatt peak-powers can be efficiently deposited on a capacitor-collector structure far away from the target and lead to the rapid (tens of nanoseconds) generation of large quasi-static electric fields over wide (tens-of-centimeters scale-length) regions, with intensities much higher than common ElectroMagnetic Pulses (EMPs) generated by the same experiment in the same position. A good agreement was obtained between measurements from a classical field-probe and calculations based on particle-flux measurements from a Thomson spectrometer. Proof-of-principle particle-in-cell simulations reproduced the measurements of field evolution in time, giving a useful insight into the charging process, generation and distribution of fields. The understanding of this charging phenomenon and of the related intense fields, which can reach the MV/m order and in specific configurations might also exceed it, is very important for present and future facilities studying laser-plasma-acceleration and inertial-confinement-fusion, but also for application to the conditioning of accelerated charged-particles, the generation of intense electric and magnetic fields and many other multidisciplinary high-power laser-driven processes.

Journal article

Dann SJD, Baird CD, Bourgeois N, Chekhlov O, Eardley S, Gregory CD, Gruse J-N, Hah J, Hazra D, Hawkes SJ, Hooker CJ, Krushelnick K, Manles SPD, Marshall VA, Murphy CD, Najmudin Z, Nees JA, Osterhoff J, Parry B, Pourmoussavi P, Rahul S, Rajeev PP, Rozario S, Scott JDE, Smith RA, Springate E, Tang Y, Tata S, Thomas AGR, Thornton C, Symes DR, Streeter MJet al., 2019, Laser wakefield acceleration with active feedback at 5 Hz, Physical Review Accelerators and Beams, Vol: 22, ISSN: 2469-9888

We describe the use of a genetic algorithm to apply active feedback to a laser wakefield accelerator at a higher power (10 TW) and a lower repetition rate (5 Hz) than previous work. The temporal shape of the drive laser pulse was adjusted automatically to optimize the properties of the electron beam. By changing the software configuration, different properties could be improved. This included the total accelerated charge per bunch, which was doubled, and the average electron energy, which was increased from 22 to 27 MeV. Using experimental measurements directly to provide feedback allows the system to work even when the underlying acceleration mechanisms are not fully understood, and, in fact, studying the optimized pulse shape might reveal new insights into the physical processes responsible. Our work suggests that this technique, which has already been applied with low-power lasers, can be extended to work with petawatt-class laser systems.

Journal article

McIlvenny A, Doria D, Romagnani L, Ahmed H, Martin P, WIlliamson SDR, Ditter EJ, Ettlinger O, Hicks GS, McKenna P, Najmudin Z, Neely D, Kar S, Borghesi Met al., 2019, Absolute calibration of microchannel plate detector for carbon ions up to 250 MeV, 5th International Conference on Frontiers in Diagnostics Technologies, Publisher: IOP PUBLISHING LTD, ISSN: 1748-0221

Conference paper

King M, Butler NMH, Wilson R, Capdessus R, Grays RJ, Powell HW, Dance RJ, Padda H, Gonzalez-Izquierdo B, Rusby DR, Dover NP, Hicks GS, Ettlinger OC, Scullion C, Carroll DC, Najmudin Z, Borghesi M, Neely D, McKenna Pet al., 2019, Role of magnetic field evolution on filamentary structure formation in intense laser-foil interactions, HIGH POWER LASER SCIENCE AND ENGINEERING, Vol: 7, ISSN: 2095-4719

Journal article

Hussein AE, Senabulya N, Ma Y, Streeter MJV, Kettle B, Dann SJD, Albert F, Bourgeois N, Cipiccia S, Cole JM, Finlay O, Gerstmayr E, Gonzalez IG, Higginbotham A, Jaroszynski DA, Falk K, Krushelnick K, Lemos N, Lopes NC, Lumsdon C, Lundh O, Mangles SPD, Najmudin Z, Rajeev PP, Schleputz CM, Shahzad M, Smid M, Spesyvtsev R, Symes DR, Vieux G, Willingale L, Wood JC, Shahani AJ, Thomas AGRet al., 2019, Laser-wakefield accelerators for high-resolution X-ray imaging of complex microstructures, Scientific Reports, Vol: 9, Pages: 1-13, ISSN: 2045-2322

Laser-wakefield accelerators (LWFAs) are high acceleration-gradient plasma-based particle accelerators capable of producing ultra-relativistic electron beams. Within the strong focusing fields of the wakefield, accelerated electrons undergo betatron oscillations, emitting a bright pulse of X-rays with a micrometer-scale source size that may be used for imaging applications. Non-destructive X-ray phase contrast imaging and tomography of heterogeneous materials can provide insight into their processing, structure, and performance. To demonstrate the imaging capability of X-rays from an LWFA we have examined an irregular eutectic in the aluminum-silicon (Al-Si) system. The lamellar spacing of the Al-Si eutectic microstructure is on the order of a few micrometers, thus requiring high spatial resolution. We present comparisons between the sharpness and spatial resolution in phase contrast images of this eutectic alloy obtained via X-ray phase contrast imaging at the Swiss Light Source (SLS) synchrotron and X-ray projection microscopy via an LWFA source. An upper bound on the resolving power of 2.7 ± 0.3 μm of the LWFA source in this experiment was measured. These results indicate that betatron X-rays from laser wakefield acceleration can provide an alternative to conventional synchrotron sources for high resolution imaging of eutectics and, more broadly, complex microstructures.

Journal article

Nghiem PAP, Alesini D, Aschikhin A, Assmann RW, Audet T, Beck A, Chance A, Chen M, Chiadroni E, Cianchi A, Clarke JA, Couprie ME, Croia M, Cros B, Dattoli G, Del Dotto A, Delerue N, Dorda U, Pousa AF, Ferrario M, Fonseca RA, Ghaith A, Giribono A, Gizzi LA, Helm A, Hidding B, Hooker SM, Ibison MG, Jaroszynski DA, Kruchinin KO, Labate L, Lee P, Li X, Li FY, Libov V, Marchetti B, de la Ossa AM, Marx D, Massimo F, Mathieu F, Maynard G, Mazzotta Z, Mehrling TJ, Molodozhentsev AY, Mosnier A, Mostacci A, Najmudin Z, Nguyen F, Niknejadi P, Espinos DO, Pattathil R, Pompili R, Romeo S, Rossi AR, Schaper L, Sheng ZM, Shpakov V, Silva LO, Silva T, Simon C, Specka A, Stella A, Streeter MJV, Svystun EN, Symes D, Terzani D, Toci G, Tomassini P, Vaccarezza C, Vieira JM, Vujanovic M, Walczak R, Walker PA, Weikum MK, Welsch CP, Weng SM, Wiggins SM, Wolfenden J, Yoffe S, Zhu Jet al., 2019, EuPRAXIA, A STEP TOWARD A PLASMA-WAKEFIELD BASED ACCELERATOR WITH HIGH BEAM QUALITY, 10th International Particle Accelerator Conference (IPAC), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588

Conference paper

Weikum MK, Akhter T, Alesini PD, Alexandrova AS, Anania MP, Andreev NE, Andriyash I, Aschikhin A, Assmann RW, Audet T, Bacci A, Barna IF, Beaton A, Beck A, Beluze A, Bernhard A, Bielawski S, Bisesto FG, Brandi F, Bringer O, Brinkmann R, Bruendermann E, Buescher M, Bussmann M, Bussolino GC, Chance A, Chanteloup JC, Chen M, Chiadroni E, Cianchi A, Clarke J, Cole J, Couprie ME, Croia M, Cros B, Crump P, Dattoli G, Delerue N, Delferriere O, Delinikolas P, De Nicola S, Dias J, Dorda U, Fedele R, Pousa AF, Ferrario M, Filippi F, Fils J, Fiore G, Fonseca RA, Galimberti M, Gallo A, Garzella D, Gastinel P, Giove D, Giribono A, Gizzi LA, Gruener FJ, Habib AF, Heinemann T, Hidding B, Holzer BJ, Hooker SM, Hosokai T, Huebner M, Irman A, Jafarinia F, Jaroszynski DA, Jaster-Merz S, Joshi C, Kaluza MC, Kando M, Karger OS, Karsch S, Khazanov E, Khikhlukha D, Knetsch A, Kocon D, Koester P, Kononenko O, Korn G, Kostyukov I, Kruchinin K, Labate L, Lechner C, Leemans WP, Lehrach A, Li FY, Li X, Libov V, Lifschitz A, Litvinenko V, Lu W, Lundh O, Maier AR, Malka V, Manahan GG, Mangles SPD, Marchetti B, Marocchino A, de la Ossa AM, Martins JL, Mason P, Massimo F, Mathieu F, Maynard G, Mazzotta Z, Mehrling TJ, Molodozhentsev AY, Mostacci A, Mueller AS, Murphy CD, Najmudin Z, Nghiem PAP, Nguyen F, Niknejadi P, Osterhoff J, Papadopoulos D, Patrizi B, Petrillo V, Pocsai MA, Poder K, Pompili R, Pribyl L, Pugacheva D, Romeo S, Rajeev PP, Conti MR, Rossi AR, Rossmanith R, Roussel E, Sahai AA, Sarri G, Schaper L, Scherkl P, Schramm U, Schroeder CB, Schwindling J, Scifo J, Serafini L, Sheng ZM, Silva LO, Silva T, Simon C, Sinha U, Specka A, Streeter MJ, Svystun EN, Symes D, Szwaj C, Tauscher G, Terzani D, Thompson N, Toci G, Tomassini P, Torres R, Ullmann D, Vaccarezza C, Vannini M, Vieira JM, Villa F, Wahlstrom C-G, Walczak R, Walker PA, Wang K, Welsch CP, Wolfenden J, Xia G, Yabashi M, Yu L, Zhu J, Zigler Aet al., 2019, EuPRAXIA - A Compact, Cost-Efficient Particle and Radiation Source, 25th International Conference on the Application of Accelerators in Research and Industry (CAARI), Publisher: AMER INST PHYSICS, ISSN: 0094-243X

Conference paper

Najmudin Z, 2019, Laser Wakefield Accelerators: Plasma Wave Growth and Acceleration, Pages: 51-70, ISSN: 0930-8989

Laser wakefield accelerators are now becoming established as indispensable laboratory tools. This is because of their ability to produce high energy electron beams in compact configurations. Here we outline the basic theory of laser wakefield acceleration. One dimensional plasma waves are considered and the differential equation for wakefield generation is derived. The case of wakefield generation at low laser intensity ((formula presented)) is considered to demonstrate the relation between the laser driver and the generated plasma wave. Finally acceleration in the plasma wave is considered. The importance of non-linear and three dimensional effects on the plasma wave growth are discussed.

Conference paper

Spesyvtsev R, Brunetti E, Vieux G, Shahzad M, Maitrallain A, Yoffe S, Ersfeld B, Kornaszewski A, Streeter MJ, Finlay O, Ma Y, Kettle B, Dann SJD, Albert F, Bourgeois N, Cipiccia S, Cole JM, Gerstmayr E, Gonzalez IG, Higginbotham A, Hussein AE, Falk K, Krushelnick K, Lemos N, Lopes NC, Lumsdon C, Lundh O, Mangles SPD, Najmudin Z, Rajeev PP, Smid M, Symes DR, Thomas AGR, Jaroszynski DAet al., 2019, Generation of electron high energy beams with a ring-like structure by a dual stage laser wakefield accelerator, Conference on Relativistic Plasma Waves and Particle Beams as Coherent and Incoherent Radiation Sources III, Publisher: SPIE-INT SOC OPTICAL ENGINEERING, ISSN: 0277-786X

Conference paper

Weikum MK, Akhter T, Alesini D, Alexandrova AS, Anania MP, Andreev NE, Andriyash IA, Aschikhin A, Assmann RW, Audet T, Bacci A, Barna IF, Beaton A, Beck A, Beluze A, Bernhard A, Bielawski S, Bisesto FG, Brandi F, Brinkmann R, Bruendermann E, Buescher M, Bussmann MH, Bussolino G, Chance A, Chen M, Chiadroni E, Cianchi A, Clarke JA, Cole J, Couprie ME, Croia M, Cros B, Crump PA, Dattoli G, Del Dotto A, Delerue N, De Nicola S, Dias JM, Dorda U, Fedele R, Pousa AF, Ferrario M, Filippi F, Fiore G, Fonseca RA, Galimberti M, Gallo A, Ghaith A, Giove D, Giribono A, Gizzi LA, Gruener FJ, Habib AF, Haefner C, Heinemann T, Hidding B, Holzer BJ, Hooker SM, Hosokai T, Huebner M, Irman A, Jafarinia FJ, Jaroszynski DA, Joshi C, Kaluza M, Kando M, Karger OS, Karsch S, Khazanov E, Khikhlukha D, Knetsch A, Kocon D, Koester P, Kononenko OS, Korn G, Kostyukov I, Kruchinin KO, Labate L, Le Blanc C, Lechner C, Leemans W, Lehrach A, Li X, Libov V, Lifschitz A, Litvinenko V, Lu W, Lundh O, Maier AR, Malka V, Manahan GG, Mangles SPD, Marchetti B, de la Ossa AM, Martins JL, Mason PD, Massimo F, Mathieu F, Maynard G, Mazzotta Z, Molodozhentsev AY, Mostacci A, Mueller A-S, Murphy CD, Najmudin Z, Nghiem PAP, Nguyen F, Niknejadi P, Osterhoff J, Espinos DO, Papadopoulos DN, Patrizi B, Petrillo V, Pocsai MA, Poder K, Pompili R, Pribyl L, Pugacheva D, Rajeev PP, Romeo S, Conti MR, Rossi AR, Rossmanith R, Roussel E, Sahai AA, Sarri G, Schaper L, Scherkl P, Schramm U, Schroeder CB, Scifo J, Serafini L, Sheng ZM, Siders C, Silva LO, Silva T, Simon C, Sinha U, Specka A, Streeter MJV, Svystun EN, Symes D, Szwaj C, Tauscher GE, Terzani D, Thompson N, Toci G, Tomassini P, Torres R, Ullmann D, Vaccarezza C, Vannini M, Vieira JM, Villa F, Wahlstrom C-G, Walczak R, Walker PA, Wang K, Welsch CP, Wiggins SM, Wolfenden J, Xia G, Yabashi M, Zhu J, Zigler Aet al., 2019, Status of the Horizon 2020 EuPRAXIA conceptual design study, 10th International Particle Accelerator Conference (IPAC), Publisher: IOP PUBLISHING LTD, ISSN: 1742-6588

Conference paper

Warwick JR, Alejo A, Dzelzainis T, Schumaker W, Doria D, Romagnani L, Poder K, Cole JM, Yeung M, Krushelnick K, Mangles SPD, Najmudin Z, Samarin GM, Symes D, Thomas AGR, Borghesi M, Sarri Get al., 2018, General features of experiments on the dynamics of laser-driven electron-positron beams, Nuclear Instruments and Methods in Physics Research Section A: Accelerators, Spectrometers, Detectors and Associated Equipment, Vol: 909, Pages: 95-101, ISSN: 0168-9002

The experimental study of the dynamics of neutral electron–positron beams is an emerging area of research, enabled by the recent results on the generation of this exotic state of matter in the laboratory. Electron–positron beams and plasmas are believed to play a major role in the dynamics of extreme astrophysical objects such as supermassive black holes and pulsars. For instance, they are believed to be the main constituents of a large number of astrophysical jets, and they have been proposed to significantly contribute to the emission of gamma-ray bursts and their afterglow. However, despite extensive numerical modelling and indirect astrophysical observations, a detailed experimental characterisation of the dynamics of these objects is still at its infancy. Here, we will report on some of the general features of experiments studying the dynamics of electron–positron beams in a fully laser-driven setup.

Journal article

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