Articles de revues : « Laser-based ion acceleration »

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Sommer, P., J. Metzkes-Ng, F.-E. Brack, T. E. Cowan, S. D. Kraft, L. Obst, M. Rehwald, H.-P. Schlenvoigt, U. Schramm et K. Zeil. « Laser-ablation-based ion source characterization and manipulation for laser-driven ion acceleration ». Plasma Physics and Controlled Fusion 60, n^o 5 (16 mars 2018) : 054002. http://dx.doi.org/10.1088/1361-6587/aab21e.

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Tayyab, M., S. Bagchi, J. A. Chakera, D. K. Avasthi, R. Ramis, A. Upadhyay, B. Ramakrishna, T. Mandal et P. A. Naik. « Mono-energetic heavy ion acceleration from laser plasma based composite nano-accelerator ». Physics of Plasmas 25, n^o 12 (décembre 2018) : 123102. http://dx.doi.org/10.1063/1.5053640.

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Uesaka, Mitsuru, et Kazuyoshi Koyama. « Advanced Accelerators for Medical Applications ». Reviews of Accelerator Science and Technology 09 (janvier 2016) : 235–60. http://dx.doi.org/10.1142/s1793626816300115.

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We review advanced accelerators for medical applications with respect to the following key technologies: (i) higher RF electron linear accelerator (hereafter “linac”); (ii) optimization of alignment for the proton linac, cyclotron and synchrotron; (iii) superconducting magnet; (iv) laser technology. Advanced accelerators for medical applications are categorized into two groups. The first group consists of compact medical linacs with high RF, cyclotrons and synchrotrons downsized by optimization of alignment and superconducting magnets. The second group comprises laser-based acceleration systems aimed of medical applications in the future. Laser plasma electron/ion accelerating systems for cancer therapy and laser dielectric accelerating systems for radiation biology are mentioned. Since the second group has important potential for a compact system, the current status of the established energy and intensity and of the required stability are given.

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Torrisi, Lorenzo, Lucia Calcagno, Mariapompea Cutroneo, Jan Badziak, Marcin Rosinski, Agnieszka Zaras-Szydlowska et Alfio Torrisi. « Nanostructured targets for TNSA laser ion acceleration ». Nukleonika 61, n^o 2 (1 juin 2016) : 103–8. http://dx.doi.org/10.1515/nuka-2016-0018.

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AbstractNanostructured targets, based on hydrogenated polymers with embedded nanostructures, were prepared as thin micrometric foils for high-intensity laser irradiation in TNSA regime to produce high-ion acceleration. Experiments were performed at the PALS facility, in Prague, by using 1315 nm wavelength, 300 ps pulse duration and an intensity of 1016W/cm2and at the IPPLM, in Warsaw, by using 800 nm wavelength, 40 fs pulse duration, and an intensity of 1019W/cm2. Forward plasma diagnostic mainly uses SiC detectors and ion collectors in time of flight (TOF) configuration. At these intensities, ions can be accelerated at energies above 1 MeV per nucleon. In presence of Au nanoparticles, and/or under particular irradiation conditions, effects of resonant absorption can induce ion acceleration enhancement up to values of the order of 4 MeV per nucleon.

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Weichman, K., A. P. L. Robinson, M. Murakami, J. J. Santos, S. Fujioka, T. Toncian, J. P. Palastro et A. V. Arefiev. « Progress in relativistic laser–plasma interaction with kilotesla-level applied magnetic fields ». Physics of Plasmas 29, n^o 5 (mai 2022) : 053104. http://dx.doi.org/10.1063/5.0089781.

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We report on progress in the understanding of the effects of kilotesla-level applied magnetic fields on relativistic laser–plasma interactions. Ongoing advances in magnetic-field–generation techniques enable new and highly desirable phenomena, including magnetic-field–amplification platforms with reversible sign, focusing ion acceleration, and bulk-relativistic plasma heating. Building on recent advancements in laser–plasma interactions with applied magnetic fields, we introduce simple models for evaluating the effects of applied magnetic fields in magnetic-field amplification, sheath-based ion acceleration, and direct laser acceleration. These models indicate the feasibility of observing beneficial magnetic-field effects under experimentally relevant conditions and offer a starting point for future experimental design.

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Schumacher, D. W., P. L. Poole, C. Willis, G. E. Cochran, R. Daskalova, J. Purcell et R. Heery. « Liquid Crystal Targets and Plasma Mirrors For Laser Based Ion Acceleration ». Journal of Instrumentation 12, n^o 04 (27 avril 2017) : C04023. http://dx.doi.org/10.1088/1748-0221/12/04/c04023.

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Cutroneo, Mariapompea, Lorenzo Torrisi, Jan Badziak, Marcin Rosinski, Vladimir Havranek, Anna Mackova, Petr Malinsky et al. « Graphite oxide based targets applied in laser matter interaction ». EPJ Web of Conferences 167 (2018) : 02004. http://dx.doi.org/10.1051/epjconf/201816702004.

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In the present work, we propose the production of a hybrid graphene based material suitable to be laser irradiated with the aim to produce quasi-monoenergetic proton beams using a femtosecond laser system. The unique lattice structure of the irradiated solid thin target can affect the inside electron propagation, their outgoing from the rear side of a thin foil, and subsequently the plasma ion acceleration. The produced targets, have been characterized in composition, roughness and structure and for completeness irradiated. The yield and energy of the ions emitted from the laser-generated plasma have been monitored and the emission of proton stream profile exhibited an acceleration of the order of several MeVs/charge state.

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Chagovets, Timofej, Stanislav Stanček, Lorenzo Giuffrida, Andriy Velyhan, Maksym Tryus, Filip Grepl, Valeriia Istokskaia et al. « Automation of Target Delivery and Diagnostic Systems for High Repetition Rate Laser-Plasma Acceleration ». Applied Sciences 11, n^o 4 (13 février 2021) : 1680. http://dx.doi.org/10.3390/app11041680.

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Fast solid target delivery and plasma-ion detection systems have been designed and developed to be used in high intensity laser-matter interaction experiments. We report on recent progress in the development and testing of automated systems to refresh solid targets at a high repetition rate during high peak power laser operation (>1 Hz), along with ion diagnostics and corresponding data collection and real-time analysis methods implemented for future use in a plasma-based ion acceleration beamline for multidisciplinary user applications.

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Torrisi, Lorenzo, Mariapompea Cutroneo et Jiri Ullschmied. « HYDROGENATED TARGETS FOR HIGH ENERGY PROTON GENERATION FROM LASER IRRADIATING IN TNSA REGIME ». Acta Polytechnica 55, n^o 3 (30 juin 2015) : 199–202. http://dx.doi.org/10.14311/ap.2015.55.0199.

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<p>Polyethylene-based thin targets were irradiated in high vacuum in the TNSA (Target Normal Sheath Acceleration) regime using the PALS laser facility. The plasmais produced in forward direction depending on the laser irradiation conditions, the composition of the target and the geometry. The optical properties of the polymer use nanostructures to increase the laser absorbance. Proton kinetic energies from hundreds keV up to about 3MeV were obtained for optimal conditions enhancing the electric field driving the ion acceleration.</p>

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Li, Dongyu, Tang Yang, Minjian Wu, Zhusong Mei, Kedong Wang, Chunyang Lu, Yanying Zhao et al. « Introduction of Research Work on Laser Proton Acceleration and Its Application Carried out on Compact Laser–Plasma Accelerator at Peking University ». Photonics 10, n^o 2 (28 janvier 2023) : 132. http://dx.doi.org/10.3390/photonics10020132.

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Laser plasma acceleration has made remarkable progress in the last few decades, but it also faces many challenges. Although the high gradient is a great potential advantage, the beam quality of the laser accelerator has a certain gap, or it is different from that of traditional accelerators. Therefore, it is important to explore and utilize its own features. In this article, some recent research progress on laser proton acceleration and its irradiation application, which was carried out on the compact laser plasma accelerator (CLAPA) platform at Peking University, have been introduced. By combining a TW laser accelerator and a monoenergetic beamline, proton beams with energies of less than 10 MeV, an energy spread of less than 1%, and with several to tens of pC charge, have been stably produced and transported in CLAPA. The beamline is an object–image point analyzing system, which ensures the transmission efficiency and the energy selection accuracy for proton beams with large initial divergence angle and energy spread. A spread-out Bragg peak (SOBP) is produced with high precision beam control, which preliminarily proved the feasibility of the laser accelerator for radiotherapy. Some application experiments based on laser-accelerated proton beams have also been carried out, such as proton radiograph, preparation of graphene on SiC, ultra-high dose FLASH radiation of cancer cells, and ion-beam trace probes for plasma diagnosis. The above applications take advantage of the unique characteristics of laser-driven protons, such as a micron scale point source, an ultra-short pulse duration, a wide energy spectrum, etc. A new laser-driven proton therapy facility (CLAPA II) is being designed and is under construction at Peking University. The 100 MeV proton beams will be produced via laser–plasma interaction by using a 2-PW laser, which may promote the real-world applications of laser accelerators in malignant tumor treatment soon.

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Brantov, Andrey V., Dmitry V. Romanov et Valery Yu Bychenkov. « Optimization of a Laser-Based Proton Source and a New Mechanism of Ion Acceleration ». IEEE Transactions on Plasma Science 44, n^o 4 (avril 2016) : 364–68. http://dx.doi.org/10.1109/tps.2015.2501436.

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Abe, Y., H. Kohri, A. Tokiyasu, T. Minami, K. Iwasaki, T. Taguchi, T. Asai et al. « A multi-stage scintillation counter for GeV-scale multi-species ion spectroscopy in laser-driven particle acceleration experiments ». Review of Scientific Instruments 93, n^o 6 (1 juin 2022) : 063502. http://dx.doi.org/10.1063/5.0078817.

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Particle counting analysis (PCA) with a multi-stage scintillation detector shows a new perspective on angularly resolved spectral characterization of GeV-scale, multi-species ion beams produced by high-power lasers. The diagnosis provides a mass-dependent ion energy spectrum based on time-of-flight and pulse-height analysis of single particle events detected through repetitive experiments. With a novel arrangement of multiple scintillators with different ions stopping powers, PCA offers potential advantages over commonly used diagnostic instruments (CR-39, radiochromic films, Thomson parabola, etc .) in terms of coverage solid angle, detection efficiency for GeV-ions, and real-time analysis during the experiment. The basic detector unit was tested using 230-MeV proton beam from a synchrotron facility, where we demonstrated its potential ability to discriminate major ion species accelerated in laser–plasma experiments (i.e., protons, deuterons, carbon, and oxygen ions) with excellent energy and mass resolution. The proposed diagnostic concept would be essential for a better understanding of laser-driven particle acceleration, which paves the way toward all-optical compact accelerators for a range of applications.

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Doria, D., P. Martin, H. Ahmed, A. Alejo, M. Cerchez, S. Ferguson, J. Fernandez-Tobias et al. « Calibration of BAS-TR image plate response to GeV gold ions ». Review of Scientific Instruments 93, n^o 3 (1 mars 2022) : 033304. http://dx.doi.org/10.1063/5.0079564.

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The response of the BAS-TR image plate (IP) was absolutely calibrated using a CR-39 track detector for high linear energy transfer Au ions up to ∼1.6 GeV (8.2 MeV/nucleon), accelerated by high-power lasers. The calibration was carried out by employing a high-resolution Thomson parabola spectrometer, which allowed resolving Au ions with closely spaced ionization states up to 58+. A response function was obtained by fitting the photo-stimulated luminescence per Au ion for different ion energies, which is broadly in agreement with that expected from ion stopping in the active layer of the IP. This calibration would allow quantifying the ion energy spectra for high energy Au ions, which is important for further investigation of the laser-based acceleration of heavy ion beams.

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Treffert, F., G. D. Glenn, H. G. J. Chou, C. Crissman, C. B. Curry, D. P. DePonte, F. Fiuza et al. « Ambient-temperature liquid jet targets for high-repetition-rate HED discovery science ». Physics of Plasmas 29, n^o 12 (décembre 2022) : 123105. http://dx.doi.org/10.1063/5.0097857.

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High-power lasers can generate energetic particle beams and astrophysically relevant pressure and temperature states in the high-energy-density (HED) regime. Recently-commissioned high-repetition-rate (HRR) laser drivers are capable of producing these conditions at rates exceeding 1 Hz. However, experimental output from these systems is often limited by the difficulty of designing targets that match these repetition rates. To overcome this challenge, we have developed tungsten microfluidic nozzles, which produce a continuously replenishing jet that operates at flow speeds of approximately 10 m/s and can sustain shot frequencies up to 1 kHz. The ambient-temperature planar liquid jets produced by these nozzles can have thicknesses ranging from hundreds of nanometers to tens of micrometers. In this work, we illustrate the operational principle of the microfluidic nozzle and describe its implementation in a vacuum environment. We provide evidence of successful laser-driven ion acceleration using this target and discuss the prospect of optimizing the ion acceleration performance through an in situ jet thickness scan. Future applications for the jet throughout HED science include shock compression and studies of strongly heated nonequilibrium plasmas. When fielded in concert with HRR-compatible laser, diagnostic, and active feedback technology, this target will facilitate advanced automated studies in HRR HED science, including machine learning-based optimization and high-dimensional statistical analysis.

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Miyatake, Tatsuhiko, Keiichiro Shiokawa, Hironao Sakaki, Nicholas P. Dover, Mamiko Nishiuchi, Hazel F. Lowe, Kotaro Kondo et al. « Denoising application for electron spectrometer in laser-driven ion acceleration using a Simulation-supervised Learning based CDAE ». Nuclear Instruments and Methods in Physics Research Section A : Accelerators, Spectrometers, Detectors and Associated Equipment 999 (mai 2021) : 165227. http://dx.doi.org/10.1016/j.nima.2021.165227.

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Ghoranneviss, M., B. Malekynia, H. Hora, G. H. Miley et X. He. « Inhibition factor reduces fast ignition threshold for laser fusion using nonlinear force driven block acceleration ». Laser and Particle Beams 26, n^o 1 (mars 2008) : 105–12. http://dx.doi.org/10.1017/s026303460800013x.

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AbstractFast ignition for fusion energy by using petawatt-picosecond (PW-ps) laser pulses was modified due to an anomaly based on extremely clean suppression of prepulses. The resulting plasma blocks with space charge neutral ion current densities above 1011Amp/cm2may be used to ignite deuterium-tritium at densities at or little above solid state density. The difficulty is to produce extremely high energy flux densities of the blocks. Results are reported how the threshold can be reduced by a factor up to fife if the inhibition factor for thermal conductivity due to electric double layers is included in the hydrodynamic analysis.

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Zimmer, Marc, Stefan Scheuren, Annika Kleinschmidt, Alexandra Tebartz, Tina Ebert, Johannes Ding, Daniel Hartnagel et Markus Roth. « Development of a Setup for Material Identification Based on Laser-Driven Neutron Resonance Spectroscopy ». EPJ Web of Conferences 231 (2020) : 01006. http://dx.doi.org/10.1051/epjconf/202023101006.

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With the phasing out of many research reactors over the upcoming years, a shortcoming of small and medium sized neutron sources is to be expected. Laser-driven neutron sources have the potential to fill this void, with enormous progress being made in laser technology over the past years. Upcoming petawatt lasers with high repetition rates up to 10 Hz promise a tremendous increase in neutron flux. In this paper, a setup is developed and optimized to conduct neutron resonance spectroscopy at a laser-driven neutron source. This setup is then evaluated at an experimental campaign at the PHELIX laser system. Laser intensities up to 1021 W/cm² with a ns pre-pulse contrast of 10-7 were used for ion acceleration, resulting in (1.8±0.7)×108 N/sr per pulse corresponding to (2.3±1.0)×109 N in a 4 π equivalent. These pulses were moderated, collimated and investigated via the time of flight method in order to characterize the thermal neutron spectrum as well as the signal to noise ratio.

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HORA, HEINRICH. « New aspects for fusion energy using inertial confinement ». Laser and Particle Beams 25, n^o 1 (28 février 2007) : 37–45. http://dx.doi.org/10.1017/s0263034607070073.

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Magnetic confinement fusion (MCF) based on neutral particle beam irradiation reached the highest gains with JET and is discussed in relation to the ITER project for a possible re-orientation with respect to the ignition process. Ignition plays a similar role for inertial confinement fusion (ICF). After a short review about specific ICF developments, the fast igniter development offered a re-consideration of igniting DT fuel at modest or low compression. The observation of extreme anomalies (Sauerbrey 1996, Zhanget al., 1998 and Badziaket al., 1999) at interaction of picosecond (ps) laser pulses above TW power could be explained as a skin layer mechanism based on earlier computations (Horaet al., 2002) with nonlinear (ponderomotive) force acceleration. The resulting very high ion current density space charge neutral plasma blocks interacting as pistons to ignite DT may lead to a new scheme of laser fusion with low cost energy generation.

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Архипов, М. В., Р. М. Архипов et Н. Н. Розанов. « Генерация униполярных импульсов терагерцового излучения с большой электрической площадью ». Оптика и спектроскопия 130, n^o 8 (2022) : 1216. http://dx.doi.org/10.21883/os.2022.08.52908.3703-22.

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A physical situation is proposed and theoretically analyzed, in which, in our opinion, it is possible to generate unipolar terahertz pulses with a large electric area. In this case, the gas in the tube is excited by a femtosecond IR laser pulse. In this case, the tube with gas is placed in a constant external electric field. The generation of a unipolar pulse is based on ”three-step scheme" - ionization of gas atoms by a femtosecond pulse, subsequent acceleration of a free electron in a dc external field and subsequent annihilation of an electron upon collision with a tube wall or another atom (ion).

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Hoffmann, Dieter H. H. « Editorial from the Editor in Chief : Impact factors and open access publishing ». Laser and Particle Beams 24, n^o 4 (octobre 2006) : 467–68. http://dx.doi.org/10.1017/s0263034606060769.

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The primary goal of Laser and Particle Beams as part of the Cambridge University Press is the dissemination of knowledge in our research field. How effective we are in this respect is not easy to determine. But the impact factor published annually in June by Thomson ISI® 2005 Journal Citation Reports (JCR), gives at least an indication and a method to compare other journals in the field. In this respect, Laser and Particle Beams is a journal with a very high ranking in the field of applied physics, but it also compares very well to journals in other field of physics. The impact factor of a journal gives an account of how often an average paper in the journal is referred to, in a two year time span after publication. The current impact factor of 2.59 is based on an evaluation conducted in 2005 of Laser and Particle Beams publications of 2003 and 2004. During the evaluation period (2005), Laser and Particle Beams publications were cited about 1000 times. The topics that attracted most attention were Fast Ignition (Deutsch, 2004; Mulser & Schneider, 2004a; Hora, 2004; Mulser & Bauer, 2004b), Inertial Fusion Targets (Borisenko et al., 2003), and Ion and Electron Acceleration in laser plasma and Ultrashort Pulses (Shorokhov & Pukhov, 2004; Osman et al., 2004; Malka & Fritzler, 2004; Limpouch et al., 2004; Pegoraro et al., 2004). However, the editorial boards of Laser and Particle Beams strongly encourage authors to submit their results in High Energy Density Physics, the emerging field of Warm Dense Matter, Pulsed Power and Accelerator Physics and Technology.

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Huang, Shenghong, Jiawei Zhang, Juchun Ding et Xisheng Luo. « Richtmyer--Meshkov instability with ionization at extreme impact conditions ». Physics of Fluids 34, n^o 7 (juillet 2022) : 072101. http://dx.doi.org/10.1063/5.0095991.

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Richtmyer–Meshkov instability (RMI) under extreme impacting conditions is studied via molecular dynamics (MD) simulation with an electron force field (eFF) model. It is revealed that the strong loading ionizes materials into heavy ions and free electrons, and subsequently, a quasi-steady electron/ion separation zone is established across the shock front because free electrons can move quickly to regions ahead of the shock wave. The electron/ion separation zone propagates at the same velocity as that of the shock wave, and its width and strength remain nearly constant. Based on this observation, a simple charge distribution profile is proposed for microscopic RMI with ionization, with which an analytical model for interface acceleration caused by electric field force can be derived. A nondimensional parameter ( η), which is defined as the ratio of the flow domain length to the length of the charge separation zone, is proposed. When η exceeds a certain value, the charge density distribution is similar to that of macroscopic RMI with ionization, and thus, an acceleration model for macroscopic RMI can be derived. Finally, a nonlinear model for the perturbation growth of macroscopic RMI with ionization is achieved by incorporating the acceleration model to the potential flow theory of Q. Zhang and W. Guo [“Universality of finger growth in two-dimensional Rayleigh–Taylor and Richtmyer–Meshkov instabilities with all density ratios,” J. Fluid Mech. 786, 47–61 (2016)]. The validity of the model is verified by the present large-scale eFF MD simulation and experimental results obtained with the Nova laser.

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Russell, Evan, Valeria Istokskaia, Lorenzo Giuffrida, Yoann Levy, Jaroslav Huynh, Martin Cimrman, Martin Srmž et Daniele Margarone. « TOF Analysis of Ions Accelerated at High Repetition Rate from Laser-Induced Plasma ». Applied Sciences 12, n^o 24 (19 décembre 2022) : 13021. http://dx.doi.org/10.3390/app122413021.

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The generation, detection, and quantification of high-energy proton spectra that are produced from laser-target interaction methodologies is a field of increasingly growing popularity over the last 20 years. Generation methods such as target normal sheath acceleration or similar allow for collimated laminar ion beams to be produced in a compact environment through the use of short-burst terawatt lasers and are a growing field of investment. This project details the development and refinement of a python-based code to analyze time-of-flight ion spectroscopy data, with the intent to pinpoint the maximum proton energy within the incident beam to as reliable and accurate a value as possible within a feasible processing time. TOF data for 2.2 × 1016 W/cm2 intensity laser shots incident on a 2 mm Cu target that were gathered from the PERLA 1 kHz laser at the HiLASE center were used as training and testing data with the implementation of basic machine learning techniques to train these methods to the data being used. These datasets were used to ensure more widely applicable functionality, and accurate calculation to within 1% accuracy of an assumed correct value was seen to be consistently achievable for these datasets. This wider functionality indicates a high level of accuracy for previously unseen TOF datasets, regardless of signal/noise levels or dataset size, allowing for free use of the code in the wider field.

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Arkhipov M. V., Arkhipov R. M. et Rosanov N. N. « Generation of unipolar pulses of terahertz radiation with a large electric area ». Optics and Spectroscopy 130, n^o 8 (2022) : 980. http://dx.doi.org/10.21883/eos.2022.08.54771.3703-22.

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A physical situation is proposed and theoretically analyzed, in which, in our opinion, it is possible to generate unipolar terahertz pulses with a large electric area. In this case, the gas in the tube is excited by a femtosecond IR laser pulse. In this case, the tube with gas is placed in a constant external electric field. The generation of a unipolar pulse is based on "three-step scheme" --- ionization of gas atoms by a femtosecond pulse, subsequent acceleration of a free electron in a dc external field and subsequent annihilation of an electron upon collision with a tube wall or another atom (ion). Keywords: unipolar pulses, ultrafast optics, electric pulse area, terahertz radiation, three-step model.

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Satta, Mauro, Mattea Carmen Castrovilli, Francesca Nicolanti, Anna Rita Casavola, Carlo Mancini Terracciano et Antonella Cartoni. « Perspectives of Gas Phase Ion Chemistry : Spectroscopy and Modeling ». Condensed Matter 7, n^o 3 (21 juillet 2022) : 46. http://dx.doi.org/10.3390/condmat7030046.

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The study of ions in the gas phase has a long history and has involved both chemists and physicists. The interplay of their competences with the use of very sophisticated commercial and/or homemade instrumentations and theoretical models has improved the knowledge of thermodynamics and kinetics of many chemical reactions, even if still many stages of these processes need to be fully understood. The new technologies and the novel free-electron laser facilities based on plasma acceleration open new opportunities to investigate the chemical reactions in some unrevealed fundamental aspects. The synchrotron light source can be put beside the FELs, and by mass spectrometric techniques and spectroscopies coupled with versatile ion sources it is possible to really change the state of the art of the ion chemistry in different areas such as atmospheric and astro chemistry, plasma chemistry, biophysics, and interstellar medium (ISM). In this manuscript we review the works performed by a joint combination of the experimental studies of ion–molecule reactions with synchrotron radiation and theoretical models adapted and developed to the experimental evidence. The review concludes with the perspectives of ion–molecule reactions by using FEL instrumentations as well as pump probe measurements and the initial attempt in the development of more realistic theoretical models for the prospective improvement of our predictive capability.

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Salvadori, M., P. L. Andreoli, M. Cipriani, G. Cristofari, R. De Angelis, S. Malko, L. Volpe et al. « Time-of-flight methodologies with large-area diamond detectors for the effectively characterization of tens MeV protons ». Journal of Instrumentation 17, n^o 04 (1 avril 2022) : C04005. http://dx.doi.org/10.1088/1748-0221/17/04/c04005.

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Abstract A novel detector based on a polycrystalline diamond sensor is here employed in an advanced time-of-flight scheme for the characterization of energetic ions accelerated during laser-matter interactions. The optimization of the detector and of the advanced TOF methodology allow to obtain signals characterized by high signal-to-noise ratio and high dynamic range even in the most challenging experimental environments, where the interaction of high-intensity laser pulses with matter leads to effective ion acceleration, but also to the generation of strong Electromagnetic Pulses (EMPs) with intensities up to the MV/m order. These are known to be a serious threat for the fielded diagnostic systems. In this paper we report on the measurement performed with the PW-class laser system Vega 3 at CLPU (∼30 J energy, ∼1021 W/cm2 intensity, ∼30 fs pulses) irradiating solid targets, where both tens of MeV ions and intense EMP fields were generated. The data were analyzed to retrieve a calibrated proton spectrum and in particular we focus on the analysis of the most energetic portion (E > 5.8 MeV) of the spectrum showing a procedure to deal with the intrinsic lower sensitivity of the detector in the mentioned spectral-range.

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Richter, C., E. Beyreuther, Y. Dammene, W. Enghardt, M. Kaluza, L. Karsch, L. Laschinsky et al. « SU-GG-T-459 : Laser-Based Particle Acceleration for Future Ion Therapy : Current Status of the Joint Project OnCOOPtics with Special Focus on Beam Delivery and Dosimetry ». Medical Physics 37, n^o 6Part23 (juin 2010) : 3292. http://dx.doi.org/10.1118/1.3468857.

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Li, Liang, Lei, Hong, Li, Li, Ghaffar, Li et Xiong. « Quantitative Analysis of Piezoresistive Characteristic Based on a P-type 4H-SiC Epitaxial Layer ». Micromachines 10, n^o 10 (20 septembre 2019) : 629. http://dx.doi.org/10.3390/mi10100629.

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In this work, the piezoresistive properties of heavily doped p-type 4H-SiC at room temperature were investigated innovatively. It was verified by a field emission scanning electron microscope (FESEM), X-ray diffraction (XRD), and laser Raman spectroscopy (LRS) that the crystal quality of the epitaxial layer was good. The doping concentration and thickness of the epitaxial layer were measured by secondary ion mass spectrometry (SIMS) to be ~1.12 × 1019 cm−3 and ~1.1 μm, respectively. The 4H-SiC cantilever beam along crystal orientation was fabricated, and the fixed end of the cantilever beam was integrated with longitudinal and transverse p-type 4H-SiC piezoresistors. A good ohmic contact was formed between Ni/Ti/Al/Au and a p-type 4H-SiC piezoresistor under nitrogen environment annealing at 1050 °C for 5 min. The free end of the cantilever beam was forced to cause strain on the p-type 4H-SiC piezoresistor, and then the resistances were measured by a high precision multimeter. The experimental results illustrated that longitudinal and transverse gauge factors (GFs) of the p-type 4H-SiC piezoresistors were 26.7 and −21.5, respectively, within the strain range of 0–336με. In order to further verify the electro-mechanical coupling effect of p-type 4H-SiC, the piezoresistors on the beam were connected to the Wheatstone full-bridge circuit and the output changes were observed under cyclic loading of 0–0.5 N. The measuring results revealed that the transducer based on the 4H-SiC piezoresistive effect exhibited good linearity and hysteresis, which confirmed that p-type 4H-SiC has the potential for pressure or acceleration sensing applications.

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CHIRILĂ, C. C., C. J. JOACHAIN, N. J. KYLSTRA et R. M. POTVLIEGE. « Interaction of ultra-intense laser pulses with relativistic ions ». Laser and Particle Beams 22, n^o 3 (juillet 2004) : 203–6. http://dx.doi.org/10.1017/s0263034604223023.

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At high laser intensities, three step recollision processes such as high order harmonic generation and high-order ATI, are normally severely suppressed due to the magnetic field component of the laser pulse. However, if the laser pulse and relativistic ion beam are directed against each other, a significant increase in the frequency and the intensity of the pulse in the rest frame of the ions can occur. By performing calculations based on a Coulomb-corrected nondipole strong field approximation, we have shown that there is a range of intensities, Lorentz factors, and ion charges for which the suppression of the three step recollision processes is not severe, even for ponderomotive energies exceeding 10 keV. As an example, we consider parameters relevant to the accelerator that will be built at GSI-Darmstadt, capable of accelerating multicharged ions to Lorentz factors reaching 30.

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Cohen, Itamar, Yonatan Gershuni, Michal Elkind, Guy Azouz, Assaf Levanon et Ishay Pomerantz. « Optically Switchable MeV Ion/Electron Accelerator ». Applied Sciences 11, n^o 12 (10 juin 2021) : 5424. http://dx.doi.org/10.3390/app11125424.

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The versatility of laser accelerators in generating particle beams of various types is often promoted as a key applicative advantage. These multiple types of particles, however, are generated on vastly different irradiation setups, so that switching from one type to another involves substantial mechanical changes. In this letter, we report on a laser-based accelerator that generates beams of either multi-MeV electrons or ions from the same thin-foil irradiation setup. Switching from generation of ions to electrons is achieved by introducing an auxiliary laser pulse, which pre-explodes the foil tens of ns before irradiation by the main pulse. We present an experimental characterization of the emitted beams in terms of energy, charge, divergence, and repeatability, and conclude with several examples of prospective applications for industry and research.

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Alekseev, N. N., A. N. Balabaev, A. A. Vasilyev, Yu A. Satov, S. M. Savin, B. Yu Sharkov, A. V. Shumshurov et V. C. Roerich. « Development of laser-plasma generator for injector of C4+ ions ». Laser and Particle Beams 30, n^o 1 (19 janvier 2012) : 65–73. http://dx.doi.org/10.1017/s0263034611000693.

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AbstractThe results of the development of the ITEP accelerator carbon ion injector based on a repetition-rate CO2 laser ion source are described. The improvement includes a modified pulsed HV-feeding generator for the discharge formation in the laser gas mixture. The advanced discharge module ensures essential increase of the laser active volume and specific electrical deposition energy. The comparative computer simulations of the discharge characteristics for the improved and the prototype lasers are applied. The design and the output spatial-temporal parameters of the free-running laser “Malish-M” are shown, so the significant increase of the laser power is reached. The spatial characteristics of the laser beam obtained with diffraction calculations are compared to measured radial distribution of the energy density. The target laser intensity and the different channels of the energy loss of the laser beam in the optical scheme are estimated. Finally, the output C4+ current trace of heavy ion injector as well as the injector scheme are shown.

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Zheng, Chuan, Pavel Fedorets, Ralf Engels, Chrysovalantis Kannis, Ilhan Engin, Sören Möller, Robert Swaczyna et al. « Polarimetry for 3He Ion Beams from Laser–Plasma Interactions ». Instruments 6, n^o 4 (10 octobre 2022) : 61. http://dx.doi.org/10.3390/instruments6040061.

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We present a compact polarimeter for 3He ions with special emphasis on the analysis of short-pulsed beams accelerated during laser–plasma interactions. We discuss the specific boundary conditions for the polarimeter, such as the properties of laser-driven ion beams, the selection of the polarization-sensitive reaction in the polarimeter, the representation of the analyzing-power contour map, the choice of the detector material used for particle identification, as well as the production procedure of the required deuterated foil-targets. The assembled polarimeter has been tested using a tandem accelerator delivering unpolarized 3He ion beams, demonstrating good performance in the few-MeV range. The statistical accuracy and the deduced figure-of-merit of the polarimetry are discussed, including the count-rate requirement and the lower limit of accuracy for beam-polarization measurements at a laser-based ion source.

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Penttilä, Heikki, Olga Beliuskina, Laetitia Canete, Antoine de Roubin, Tommi Eronen, Marjut Hukkanen, Anu Kankainen et al. « Radioactive ion beam manipulation at the IGISOL-4 facility ». EPJ Web of Conferences 239 (2020) : 17002. http://dx.doi.org/10.1051/epjconf/202023917002.

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The IGISOL-4 facility in the JYFL Accelerator Laboratory of the University of Jyvaskyla (JYFL-ACCLAB) produces low-energy radioactive ion beams, primarily for nuclear spectroscopy, utilizing an ion guide-based, ISOL-type mass separator. Recently, new ion manipulation techniques have been introduced at the IGISOL-4 including the application of the PI-ICR (Phase-Imaging Ion Cyclotron Resonance) technique at the JYFLTRAP Penning trap, as well as commissioning of a Multi-Reflection Time-Of-Flight (MR-TOF) separator/spectrometer. The successful operation of the MR-TOF also required significant improvement of the Radio-Frequency Quadrupole (RFQ) cooler and buncher device beam pulse time structure. In addition, laser ionization techniques have been developed for particular cases, for example, a hot cavity laser ion source for silver production. A new stable isotope ion source and a beam line has been introduced for tuning and calibration purposes. In addition to the installations at the IGISOL-4 facility, the extension of the vacuum-mode recoil separator MARA (Mass Analysing Recoil Apparatus), MARA-LEB (MARA Low Energy Branch) has been under development. MARA-LEB will utilize the gas-cell technique and laser ionization to convert MeV-scale radioactive beams to low-energy ones.

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LEE, R. W., H. A. BALDIS, R. C. CAUBLE, O. L. LANDEN, J. S. WARK, A. NG, S. J. ROSE et al. « Plasma-based studies with intense X-ray and particle beam sources ». Laser and Particle Beams 20, n^o 3 (juillet 2002) : 527–36. http://dx.doi.org/10.1017/s0263034602202293.

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The construction of short pulse (<200 fs) tunable X-ray laser sources based on the X-ray free electron laser (XFEL) concept will be a watershed for plasma-based and warm dense matter research. These new fourth generation light sources will have extremely high fields and short wavelengths (∼0.1 nm) with peak spectral brightnesses 1010 greater than third generation sources. Further, the high intensity upgrade of the GSI accelerator facilities will lead to specific energy depositions up to 200 kJ/g and temperatures between 1 and 10 eV at almost solid-state densities, enabling interesting experiments in the regime of nonideal plasmas, such as the evolution of intense ion beams in the interior of a Jovian planet. Below we discuss several applications: the creation of warm dense matter (WDM) research, probing of near solid density plasmas, and laser–plasma spectroscopy of ions in plasmas. The study of dense plasmas has been severely hampered by the fact that laser-based methods have been unavailable and these new fourth generation sources will remove these restrictions.

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Krása, J., A. Velyhan, K. Jungwirth, E. Krouský, L. Láska, K. Rohlena, M. Pfeifer et J. Ullschmied. « Repetitive outbursts of fast carbon and fluorine ions from sub-nanosecond laser-produced plasma ». Laser and Particle Beams 27, n^o 1 (23 janvier 2009) : 171–78. http://dx.doi.org/10.1017/s0263034609000238.

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AbstractRepeated plasma outbursts were recognized at our analyzing currents of the fast carbon and fluorine ions produced with the sub-nanosecond PALS laser beam (λ0 = 1.315 µm, τL = ≈350 ps,Imax ≈ 6 × 1015 W/cm2) focused onto polytetrafluoroethylene and polyethylene targets. This study deals with a repetitive occurrence of doublets of C6+-C5+and F9+-F8+ion peaks in the time-of-flight (TOF) spectra, whose TOF can be related to the same accelerating voltage:$\tau \propto 1/\sqrt{U}$. The repeated occurrence of ion outbursts containing fully ionized ions can be characterized by a set of discrete voltagesUi, where the subscripti ∈ (1,N) labels the outbursts of ions from the fastest one (i = 1) up to the slowest and in the TOF spectrum yet distinguishable outburst (i = N). These discrete values could indicate plasma pulsations followed by repetitive outbursts of ions. The ions expand with a velocity up to ≈9 × 108 cm/s. The corresponding values of the accelerating voltage of ≈800 kv, and the temperature of ≈1.1 keV were determined by revealing partial ion currents based on the shifted Maxwell-Boltzmann velocity distribution. Characteristics of fast ion outbursts depend on the focus position with respect to the target surface.

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Huh, Sung-Ryul, Bong-Ki Jung, Jong-Gab Jo, Min Park, Seung Ho Jeong, Tae-Seong Kim et Dae-Sik Chang. « Development of a Cs-free negative hydrogen ion source system using multi-pulsed plasma sources ». Review of Scientific Instruments 93, n^o 6 (1 juin 2022) : 063503. http://dx.doi.org/10.1063/5.0068639.

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The Korea Atomic Energy Research Institute has recently proposed and developed a novel cesium-free negative hydrogen/deuterium ion source system based on two pulsed plasma sources for fusion and particle accelerator applications. The main feature of this ion source system is the use of both magnetic filters and plasma pulsing (also called the temporal filter). The system operates with two alternate pulsing sequences related to the respective plasma sources, thereby switching the plasmas in the after-glow state in an alternating manner. This study investigates the temporal behavior of deuterium negative ions in the system in a qualitative way by conducting a time-resolved measurement of laser photodetachment current commensurate with the negative ion density. In preliminary experiments, the current in the initial after-glow state remains higher than in the active-glow state identical to a steady-state continuous wave plasma, and the ratio reaches a maximum of about three times. This indicates that the pulsing gives highly efficient negative ion volume formation. Furthermore, it is observed that the time duration when the current is maintained at high values can be prolonged (or modulated) with the alternate dual pulsing, which is not possible with conventional single pulsing. These results provide a clue that the multi-pulsed ion source system may offer a continuous supply of negative ions at high densities and consequently become an alternative to cesium seeded ion sources.

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Bangerter, R. O., A. Faltens et P. A. Seidl. « Accelerators for Inertial Fusion Energy Production ». Reviews of Accelerator Science and Technology 06 (janvier 2013) : 85–116. http://dx.doi.org/10.1142/s1793626813300053.

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Since the 1970s, high energy heavy ion accelerators have been one of the leading options for imploding and igniting targets for inertial fusion energy production. Following the energy crisis of the early 1970s, a number of people in the international accelerator community enthusiastically began working on accelerators for this application. In the last decade, there has also been significant interest in using accelerators to study high energy density physics (HEDP). Nevertheless, research on heavy ion accelerators for fusion has proceeded slowly pending demonstration of target ignition using the National Ignition Facility (NIF), a laser-based facility at Lawrence Livermore National Laboratory. A recent report of the National Research Council recommends expansion of accelerator research in the US if and when the NIF achieves ignition. Fusion target physics and the economics of commercial energy production place constraints on the design of accelerators for fusion applications. From a scientific standpoint, phase space and space charge considerations lead to the most stringent constraints. Meeting these constraints almost certainly requires the use of multiple beams of heavy ions with kinetic energies >1 GeV. These constraints also favor the use of singly charged ions. This article discusses the constraints for both fusion and HEDP, and explains how they lead to the requirements on beam parameters. RF and induction linacs are currently the leading contenders for fusion applications. We discuss the advantages and disadvantages of both options. We also discuss the principal issues that must yet be resolved.

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Bakhtin, A. I., A. V. Mukhametshin, O. N. Lopatin, V. F. Valeev, V. I. Nuzhdin et R. I. Khaibullin. « Absorption spectra and crystal chemistry of quartz implanted with cobalt ions ». Proceedings of higher educational establishments. Geology and Exploration 63, n^o 5 (30 août 2021) : 57–66. http://dx.doi.org/10.32454/0016-7762-2020-63-5-57-66.

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Background. High-dose implantation of cobalt ions into the crystal structure of natural colourless quartz was carried out. Samples of crystal plates of rock crystal from the Svetlinskoye deposit in the South Urals plane-parallel were studied. All samples were crystallographically oriented perpendicular to the symmetry axis of the third order. Cobalt implantation into quartz was carried out using an ILU-3 ion-beam accelerator along the С axis of symmetry.Aim. To determine the ranges of thermal annealing for a controlled change in the sample colour and to establish the crystal-chemical features of the changes occurring in quartz matrix due to ionbeam modification of mineral properties.Materials and methods. Implantation modes included: room temperature, residual vacuum 10–5 torr, radiation dose from 1.0×1017 to 1.5×1017 ion/cm2 at a constant ion current density of 10 μA/cm2. Post-implantation heat treatment was carried out in three stages. The control of crystallochemical changes was carried out using a highly sensitive spectrophotometer with a wide range of wavelengths.Results. It was found that the revealed absorption bands are associated with electronic transitions in cobalt ions (Со2+ and Со 3+) coordinated in the crystal matrix of implanted and heat-treated rock crystal. The formation of an independent ultradispersed spinel phase in the irradiated quartz matrix was confirmed. The newly formed phase belongs to a partially reversed cobalt spinel.Conclusions. Taking into account the quantum-optical properties of cobalt spinel (laser shutters), the method of ion-beam modification of mineral crystal structures, quartz in particular, is highly promising in terms of creating new composite materials based on natural and artificial mineral raw materials.

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Crofton, Mark W., Donner T. Schoeffler, Jason A. Young et Michael J. Patterson. « Erosion Rate Measurements for DART Spacecraft Ion Propulsion System ». Applied Sciences 12, n^o 15 (4 août 2022) : 7831. http://dx.doi.org/10.3390/app12157831.

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The Double Asteroid Redirection Test (DART) spacecraft was developed to provide the first measurement for orbital deflection of an asteroid upon intentional impact. The NEXT ion engine is part of the mission, on its maiden voyage. As part of the pre-launch risk reduction, erosion characteristics of the extraction grid system were evaluated using laser measurements of sputtered molybdenum atoms over the envelope of potential throttle conditions for the mission. Erosion rate dependence on propellant flow rate as well as relative density and directionality of molybdenum sputter from grid center to edge were measured. Sputtered atoms were found to have average radial velocity directed toward the engine perimeter and increasing with radial distance. The relative contribution of source and facility background gas and other sources of accelerator grid current was examined as well as the influence of several engine operating parameters. Facility background gas was found to influence engine operation more than a wall-mounted pressure gauge and typical assumptions about ingestion would indicate. Far-field flux was estimated over the full angular range based on the near-field relative density and velocity results and relying on quartz crystal microbalance data at one location to fix absolute numbers everywhere. The results substantially deepen knowledge and understanding of the complex grid erosion process of the engine and its lifetime, as grid failure via erosion is the normal life limiter. Study results are also relevant to thruster–spacecraft integration issues such as molybdenum deposition rate on solar cells and other spacecraft surfaces.

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Hallal, Taleb, Gail P. Box, David D. Cohen et Eduard Stelcer. « Size-resolved elemental composition of aerosol particles in greater Sydney in 2002–2003 ». Environmental Chemistry 10, n^o 4 (2013) : 295. http://dx.doi.org/10.1071/en12194.

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Environmental context Atmospheric aerosols may either scatter or absorb solar radiation, potentially cooling or warming the planet. The warming–cooling effects of aerosols are determined by their optical properties, which depend on chemical composition. To better predict aerosol effects we need a good understanding of aerosol chemistry across a wide size range and geographic area. We report results of a study designed to increase understanding of the chemical composition of fine and coarse aerosols in Sydney. Abstract Between November 2002 and December 2003 samples of PM2.5 and PM10 (particulate matter less than 2.5- and 10-μm aerodynamic diameter) aerosols were collected at four sites in the Sydney Basin in order to determine the spatial and seasonal variation of size-resolved aerosol chemical composition in the Sydney region and relate this to aerosol optical properties. Accelerator-based ion beam analysis was used to determine the elemental composition and black carbon (BC) was determined using the laser integrating plate method. Aerosol species were determined by multiplying a marker element by a factor based on molecular weight ratios. Mass concentrations at the rural sites were lower than at the urban sites with an average PM2.5/PM10 mass ratio of 0.5–0.6 for all sites although at the urban sites it was 0.2–0.25 in summer. For all sites BC was the dominant element, followed by Na. For the urban sites this was followed by Cl suggesting sea salt and then the soil elements Al and Si. For the rural sites the soil elements Al, Si and Ca were more important than Cl, which was found to decrease away from the coast. Analysis of aerosol species shows that BC accounts for a larger portion of PM2.5 than PM10 and sea salt and sulfate levels are higher in summer than in winter.

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Ivanov, Yu F., V. E. Gromov, D. V. Zagulyaev, S. V. Konovalov et Yu A. Rubannikova. « Increase of alloys functional properties by electronic beam processing ». Izvestiya. Ferrous Metallurgy 64, n^o 2 (2 avril 2021) : 129–34. http://dx.doi.org/10.17073/0368-0797-2021-2-129-134.

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The article considers a review of domestic and foreign works on the use of intense pulsed electron beams for surface treatment of metals, alloys, cermet and ceramic materials. The advantages of using electron pulsed beams over laser beams, plasma flows, and ion beams are noted. The promising directions of using electron-beam processing were analyzed and are as following: 1 – smoothing the surface, getting rid of surface microcracks, while simultaneously changing the structural-phase state of the surface layer, to create high-performance technologies for the finishing processing of critical metal products of complex shape made of titanium alloy Ti-6Al-4V and titanium; steels of various classes; hard alloy WC – 10 wt. % Сo; aluminum; 2 – removal of microbursts formed during the manufacture of precision molds (SKD11 steel) and biomedical products (Ti-6Al-4V alloy); 3 – finishing the surface of molds and dies; 4 – improvement of the functional properties of metallic biomaterials: stainless steel, titanium and its alloys, alloys based on titanium nickelide with shape memory effect, and magnesium alloys; 5 – processing of medical devices and implants; 6 – formation of the surface alloys for powerful electrodynamic systems; 7 – improvement of the characteristics of aircraft engine and compressor blades; 8 – formation of thermal barrier coatings applied to the surface of the combustion chambers. It is shown that with the correct choice of process parameters, such as accelerating voltage, energy density of electron beam, number of pulses, and pulse duration, it is possible to control carefully and/or manipulate the characteristics of structural-phase state and surface properties. In order to improve the properties of the material and the durability of the products made of it, an important factor is the structure modification to form a submicro-nanosized grain (or subgrain structure).

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Cressler, John D. « Silicon-Germanium Electronics and Photonics for Space Systems ». ECS Meeting Abstracts MA2022-02, n^o 32 (9 octobre 2022) : 1199. http://dx.doi.org/10.1149/ma2022-02321199mtgabs.

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Space has been aptly called the “final frontier” (thank you, Star Trek!). The application needs of the global space and aerospace communities are predictably many and varied, ranging from a diverse set of communications and imaging satellites, to the GPS constellation, to microwave and millimeter-wave (mmW) remote sensing to support weather forecasting and climate science, to exploration of other worlds, which include: the mighty James Webb Space Telescope (probing the origins of the universe), the shadowed polar craters of the Moon (the search for water ice), Mars surface (colonization?), and Europa (the search for extraterrestrial life in the water ocean beneath the 10 km ice cap). While classically, orbital satellites were massive, tough to launch, and extremely expensive (a few $Bs), the current (and rapidly accelerating) trend has swung decidedly towards using relatively low-cost (a few $M) and easy to launch constellations of single or multi-U CubeSats (1U = 10x10x10 cm3) to cost-effectively address the plethora of emerging needs. These days, this has been increasingly supported by commercial space ventures (e.g., SpaceX, BlueOrigin et al., vs. the old gang—NASA and DoD), which are proliferating rapidly. As appealing as space is for visioning fun new science and slick applications, it remains a decidedly unfriendly place to visit. Space is the quintessential “extreme environment,” bathed in intense radiation from both our Sun (high energy electrons and protons trapped by the Earth’s magnetosphere in radiation belts) and the cosmos (GeV energy galactic cosmic rays from supernovae). By way of level setting, a satellite in the most benign Earth orbit, Low Earth Orbit (LEO – 160-1000 km up from the surface), experiences 100,000 rad of ionizing radiation dose over mission life. In comparison, 500 rad will do a person in! That is, we are asking a lot of our electronics in such systems, and given the extreme cost constraints of launch weight, adding a few inches of lead shielding is not the ideal solution! In addition, it is mighty chilly in space (2.73 K = -455°F, the cosmic background), and when the sunlight shines on you, it gets uncomfortably warm, very quickly (e.g., on the surface of the Moon, from -180°C to +120°C from darkness to light, within a few moments). Yep, space is a tough place to do business. As I have long argued [1], SiGe HBT BiCMOS technology provides a unique solution for many of the needs of these emerging space systems, including: 1) extreme levels of performance (multi-hundred GHz) with the SiGe HBT and high integration levels with on-board CMOS, for realizing compelling system functionality/unit volume, at low cost; 2) the rapid improvement of all electronic circuit relevant performance metrics with cooling, with operational capability down into the mK quantum regime (SiGe HBTs love chilly weather!); 3) the ability to operate robustly up to 150-200°C, with modest performance loss; 4) the ability to operate robustly over wide temperature ranges (in principle from mK to 150-200°C); 5) built-in robustness to multi-Mrad total ionizing dose radiation; and 6) built-in heavy ion induced latchup immunity (read: those pesky GeV cosmic rays). Long ago (1990s), the notion of creating a low-cost Si-based electronic + photonic integrated circuit (EPIC) “superchip” was envisioned (Soref), which brought together advanced SiGe HBTs (analog, RF-mmW), CMOS (digital), and Si integrated photonics (with the possible exception of a laser, which could be flipped onto the die worse case). In essence, EPICs are a low-cost, high-yielding, reliable, highly integrated Si platform for putting electrons and light into the same conversation! Clearly this represents a paradigm shift to business as usual. Now, with even more compelling system functionality/unit volume, at low cost. Such an EPIC superchip could in principle satisfy all-comers-of-new-needs. While photonics has long been used in space (think solar cells, imagers), EPICs are new to that space game, but possess great potential for the emergent needs in this new vision of CubeSat/SmallSat driven space systems, including, thing like: LIDAR (spacecraft-to-spacecraft positioning); deep space and within-constellation optical communications (huge data rate improvement); and on-spacecraft high bandwidth data transport (think data center in the sky for instruments that spew out tons of data that need to get back home quickly). This field of EPICs in space is only a few years old, but already much has been learned, and results look very encouraging. In this invited talk, I will highlight the current status and the future trends of using SiGe electronic and photonics in space systems. [1] J.D. Cressler, Proc. IEEE, vol. 93, pp. 1559-1582, 2005. Figure 1

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Kawata, Shigeo, Toshihiro Nagashima, Masahiro Takano, Takeshi Izumiyama, Daiki Kamiyama, Daisuke Barada, Qing Kong et al. « Controllability of intense-laser ion acceleration ». High Power Laser Science and Engineering 2 (1 mars 2014). http://dx.doi.org/10.1017/hpl.2014.5.

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AbstractAn ion beam has the unique feature of being able to deposit its main energy inside a human body to kill cancer cells or inside material. However, conventional ion accelerators tend to be huge in size and cost. In this paper, a future intense-laser ion accelerator is discussed to make the laser-based ion accelerator compact and controllable. The issues in the laser ion accelerator include the energy efficiency from the laser to the ions, the ion beam collimation, the ion energy spectrum control, the ion beam bunching, and the ion particle energy control. In the study, each component is designed to control the ion beam quality by particle simulations. The energy efficiency from the laser to ions is improved by using a solid target with a fine sub-wavelength structure or a near-critical-density gas plasma. The ion beam collimation is performed by holes behind the solid target or a multi-layered solid target. The control of the ion energy spectrum and the ion particle energy, and the ion beam bunching are successfully realized by a multi-stage laser–target interaction.

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Ahmed, Hamad, Prokopis Hadjisolomou, Kealan Naughton, Aaron Alejo, Stephanie Brauckmann, Giada Cantono, Simon Ferguson et al. « High energy implementation of coil-target scheme for guided re-acceleration of laser-driven protons ». Scientific Reports 11, n^o 1 (12 janvier 2021). http://dx.doi.org/10.1038/s41598-020-77997-w.

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AbstractDeveloping compact ion accelerators using intense lasers is a very active area of research, motivated by a strong applicative potential in science, industry and healthcare. However, proposed applications in medical therapy, as well as in nuclear and particle physics demand a strict control of ion energy, as well as of the angular and spectral distribution of ion beam, beyond the intrinsic limitations of the several acceleration mechanisms explored so far. Here we report on the production of highly collimated ($$\sim 0.2^{\circ }$$ ∼ 0 . 2 ∘ half angle divergence), high-charge (10s of pC) and quasi-monoenergetic proton beams up to $$\sim$$ ∼ 50 MeV, using a recently developed method based on helical coil targetry. In this concept, ions accelerated from a laser-irradiated foil are post-accelerated and conditioned in a helical structure positioned at the rear of the foil. The pencil beam of protons was produced by guided post-acceleration at a rate of $$\sim$$ ∼ 2 GeV/m, without sacrificing the excellent beam emittance of the laser-driven proton beams. 3D particle tracing simulations indicate the possibility of sustaining high acceleration gradients over extended helical coil lengths, thus maximising the gain from such miniature accelerating modules.

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Passalidis, Stylianos, Oliver C. Ettlinger, George S. Hicks, Nicholas P. Dover, Zulfikar Najmudin, Emmanouil P. Benis, Evaggelos Kaselouris, Nektarios A. Papadogiannis, Michael Tatarakis et Vasilis Dimitriou. « Hydrodynamic computational modelling and simulations of collisional shock waves in gas jet targets ». High Power Laser Science and Engineering 8 (2020). http://dx.doi.org/10.1017/hpl.2020.5.

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We study the optimization of collisionless shock acceleration of ions based on hydrodynamic modelling and simulations of collisional shock waves in gaseous targets. The models correspond to the specifications required for experiments with the $\text{CO}_{2}$ laser at the Accelerator Test Facility at Brookhaven National Laboratory and the Vulcan Petawatt system at Rutherford Appleton Laboratory. In both cases, a laser prepulse is simulated to interact with hydrogen gas jet targets. It is demonstrated that by controlling the pulse energy, the deposition position and the backing pressure, a blast wave suitable for generating nearly monoenergetic ion beams can be formed. Depending on the energy absorbed and the deposition position, an optimal temporal window can be determined for the acceleration considering both the necessary overdense state of plasma and the required short scale lengths for monoenergetic ion beam production.

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Dolier, Ewan, Martin King, Robbie Wilson, Ross Gray et Paul McKenna. « Multi-parameter Bayesian optimisation of laser-driven ion acceleration in particle-in-cell simulations ». New Journal of Physics, 1 juillet 2022. http://dx.doi.org/10.1088/1367-2630/ac7db4.

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Abstract High power laser-driven ion acceleration produces bright beams of energetic ions that have the potential to be applied in a wide range of sectors. The routine generation of optimised and stable ion beam properties is a key challenge for the exploitation of these novel sources. We demonstrate the optimisation of laser-driven proton acceleration in particle-in-cell simulations controlled by a Bayesian algorithm. Optimal laser and plasma conditions are identified four times faster for two input parameters, and approximately one thousand times faster for four input parameters, when compared to systematic and linear parametric variation. In addition, a non-trivial optimal condition for the front surface density scale length is discovered, which would have been difficult to identify by single variable scans. This approach enables rapid identification of optimal laser and target parameters in simulations, for use in guiding experiments, which has the potential to significantly accelerate the development and application of laser-plasma-based ion sources.

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Weichman, K., J. J. Santos, S. Fujioka, T. Toncian et A. V. Arefiev. « Generation of focusing ion beams by magnetized electron sheath acceleration ». Scientific Reports 10, n^o 1 (3 novembre 2020). http://dx.doi.org/10.1038/s41598-020-75915-8.

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Abstract We present the first 3D fully kinetic simulations of laser driven sheath-based ion acceleration with a kilotesla-level applied magnetic field. The application of a strong magnetic field significantly and beneficially alters sheath based ion acceleration and creates two distinct stages in the acceleration process associated with the time-evolving magnetization of the hot electron sheath. The first stage delivers dramatically enhanced acceleration, and the second reverses the typical outward-directed topology of the sheath electric field into a focusing configuration. The net result is a focusing, magnetic field-directed ion source of multiple species with strongly enhanced energy and number. The predicted improvements in ion source characteristics are desirable for applications and suggest a route to experimentally confirm magnetization-related effects in the high energy density regime. We additionally perform a comparison between 2D and 3D simulation geometry, on which basis we predict the feasibility of observing magnetic field effects under experimentally relevant conditions.

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Vladisavlevici, Iuliana-Mariana, Daniel Vizman et Emmanuel d'Humières. « Theoretical investigation of the interaction of ultra-high intensity laser pulses with near critical density plasmas ». Plasma Physics and Controlled Fusion, 23 février 2023. http://dx.doi.org/10.1088/1361-6587/acbe63.

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Abstract A theoretical model of energy transfer from laser to particles in the ultra-high intensity regime of laser plasma interaction is proposed, assuming that most of the laser energy will be transferred to hot electrons. Varying the target density and thickness, the optimal parameters for the maximum conversion efficiency of the laser energy to particles are studied. Through 2D particle-in-cell (PIC) simulations, the model is validated for a near-critical density plasma between 0.5 - 20 nc (where nc = 1.1·1021 cm-3 is the critical density for a laser wavelength of λ=1μm) irradiated by a laser pulse of intensity in the range 1020 - 1023 W/cm2 and the pulse duration in the range 6.5 - 100 fs. As an application to this model, laser ion acceleration is studied for a laser intensity of 1022 W/cm2 and a pulse duration of 20 fs. Based on the literature and new findings from our model, the optimum thickness for ion acceleration and the maximum ion energies for an expansion like mechanism are predicted. These results can be used for applications requiring high energy ions and for preparations of experiments at the Apollon and ELI laser facilities.

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Hihara, Takamasa, Masato Kanasaki, Takafumi Asai, Tamon Kusumoto, Satoshi Kodaira, Hiromitsu Kiriyama, Keiji Oda et al. « Discriminative detection of laser-accelerated multi-MeV carbon ions utilizing solid state nuclear track detectors ». Scientific Reports 11, n^o 1 (11 août 2021). http://dx.doi.org/10.1038/s41598-021-92300-1.

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AbstractA new diagnosis method for the discriminative detection of laser-accelerated multi-MeV carbon ions from background oxygen ions utilizing solid-state nuclear track detectors (SSNTDs) is proposed. The idea is to combine two kinds of SSNTDs having different track registration sensitivities: Bisphenol A polycarbonate detects carbon and the heavier ions, and polyethylene terephthalate detects oxygen and the heavier ions. The method is calibrated with mono-energetic carbon and oxygen ion beams from the heavy ion accelerator. Based on the calibration data, the method is applied to identify carbon ions accelerated from multilayered graphene targets irradiated by a high-power laser, where the generation of high-energy high-purity carbon ions is expected. It is found that 93 ± 1% of the accelerated heavy ions with energies larger than 14 MeV are carbons. The results thus obtained support that carbon-rich heavy ion acceleration is achieved.

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Măgureanu, A., L. Dincă, C. Jalbă, R. F. Andrei, I. Burducea, D. G. Ghiţă, V. Nastasa et al. « Target Characteristics Used in Laser-Plasma Acceleration of Protons Based on the TNSA Mechanism ». Frontiers in Physics 10 (1 mars 2022). http://dx.doi.org/10.3389/fphy.2022.727718.

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The target normal sheath acceleration is a robust mechanism for proton and ion acceleration from solid targets when irradiated by a high power laser. Since its discovery extensive studies have been carried out to enhance the acceleration process either by optimizing the laser pulse delivered onto the target or by utilizing targets with particular features. Targets with different morphologies such as the geometrical shape (thin foil, cone, spherical, foam-like, etc.), with different structures (multi-layer, nano- or micro-structured with periodic striations, rods, pillars, holes, etc.) and made of different materials (metals, plastics, etc.) have been proposed and utilized. Here we review some recent experiments and characterize from the target point of view the generation of protons with the highest energy.

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Snyder, Joseph, John Morrison, Scott Feister, Kyle Frische, Kevin George, Manh Le, Christopher Orban, Gregory Ngirmang, Enam Chowdhury et William Roquemore. « Background pressure effects on MeV protons accelerated via relativistically intense laser-plasma interactions ». Scientific Reports 10, n^o 1 (26 octobre 2020). http://dx.doi.org/10.1038/s41598-020-75061-1.

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Abstract We present how chamber background pressure affects energetic proton acceleration from an ultra-intense laser incident on a thin liquid target. A high-repetition-rate (100 Hz), 3.5 mJ laser with peak intensity of $$8 \times 10^{18}\,\text {Wcm}^{-2}$$ 8 × 10 18 Wcm - 2 impinged on a 450 nm sheet of flowing liquid ethylene glycol. For these parameters, we experimentally demonstrate a threshold in laser-to-proton conversion efficiency at background pressures $$< 8\,\text {Torr}$$ < 8 Torr , wherein the overall energy in ions $$>1\,\text {MeV}$$ > 1 MeV increases by an order of magnitude. Proton acceleration becomes increasingly efficient at lower background pressures and laser-to-proton conversion efficiency approaches a constant as the vacuum pressure decreases. We present two-dimensional particle-in-cell simulations and a charge neutralization model to support our experimental findings. Our experiment demonstrates that high vacuum is not required for energetic ion acceleration, which relaxes target debris requirements and facilitates applications of high-repetition rate laser-based proton accelerators.

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