NanoAc Workshop 2025
from
Thursday, 6 November 2025 (08:00)
to
Friday, 7 November 2025 (19:10)
Monday, 3 November 2025
Tuesday, 4 November 2025
Wednesday, 5 November 2025
Thursday, 6 November 2025
09:00
09:00 - 09:45
Room: Letitia Obeng
09:45
Welcome
-
Carsten Welsch
(
University of Liverpool
)
Welcome
Carsten Welsch
(
University of Liverpool
)
09:45 - 10:00
Room: Letitia Obeng
10:00
State-of-the-art of channeling of charged particles in crystals and nanostructures: Beam Channelling for Accelerator and Radiation Physics
-
Sultan Dabagov
(
INFN Lab Naz Frascati
)
State-of-the-art of channeling of charged particles in crystals and nanostructures: Beam Channelling for Accelerator and Radiation Physics
Sultan Dabagov
(
INFN Lab Naz Frascati
)
10:00 - 10:50
Room: Letitia Obeng
Channeling is the phenomenon well-known in the physics world mostly related to the propagation of the beams of charged particles in aligned crystals. Since the discovery, channeling of high-energy leptons (electrons/positrons of several MeV up to hundred of GeV energies) and hadrons (protons/ions of tens GeV up to several TeV energies) has been applied at various famous world research centres within different national/international projects related to the phenomenon utilisation to shape the beams as well as to produce high power x-ray and gamma radiation sources. However, recent studies have shown the feasibility of channeling phenomenology applica- tion for description of other various mechanisms of interaction of charged as well as neutral particles beams in solids, plasmas and electromagnetic fields covering the research fields from crystal/laser/plasma based undulators and collimators to capillary based x-ray and neutron optical elements. This talk is devoted to actual channeling related projects that have been realising since so-called renaissance of channeling studies started in the end of last century, as well as to the future possible developments in channeling (bulk and surface) physics that has been extended from the crystals to the external structured electromagnetic fields.
10:50
40 years of development of plasma wakefield acceleration
-
Guoxing Xia
(
University of Mancester
)
40 years of development of plasma wakefield acceleration
Guoxing Xia
(
University of Mancester
)
10:50 - 11:20
Room: Letitia Obeng
11:20
Coffee break
Coffee break
11:20 - 11:40
Room: Letitia Obeng
11:40
Interaction of high-intensity beam with structured solid surface plasma in relativistic regime
-
Bifeng Lei
(
UOL/CI
)
Interaction of high-intensity beam with structured solid surface plasma in relativistic regime
Bifeng Lei
(
UOL/CI
)
11:40 - 12:10
Room: Letitia Obeng
Recent research into the interaction between high-intensity beams (e.g. laser or charged particle beams) and surface plasmas has revealed significant potential for generating extremely strong fields for particle acceleration and radiation production. This new approach has emerged by overcoming several challenges in beam-solid interactions. It therefore holds great promise for reforming the research direction of large-scale facilities pursuing the energy frontier and micro-scale facilities demanding great flexibility. At the same time, this research can provide new insights into the extremely complex nonlinear dynamics of surface plasmons in the strong fields, a new unexplored regime. In this talk, I will present our recent theoretical work on the interaction between high-intensity lasers or beams and structured solid surfaces made of nanomaterials, such as well-aligned carbon nanotube (CNT) forests. It aims to achieve a TeV/m-level accelerating gradient for ultra-compact particle acceleration, as well as pushing the energy frontier [1,2,3]. Thanks to the excellent properties of relativistic surface plasmons (RSPs) on these structured nanomaterials, we can also expect to produce high-quality radiation [4]. A brief discussion of future research activities will be given, with potential facilities that could support our experimental demonstrations. References: [1] Bifeng Lei et al. 2025 Plasma Phys. Control. Fusion 67 065036 [2] Bifeng Lei et al. 2025 New J. Phys. 27 084301 [3] Cristian Bonţoiu et al. eprint: arXiv:2502.00183v2, 11 Feb 2025. In the preview process of Sci. Rep. [4] Bifeng Lei et al. eprint: arXiv:2507.04561v1, 06 Jul 2025. In the preview process of PRL.
12:10
Oriented crystals and nanostructures and their applications
-
Sytov Alexei
(
INFN Ferrara Division
)
Oriented crystals and nanostructures and their applications
Sytov Alexei
(
INFN Ferrara Division
)
12:10 - 12:40
Room: Letitia Obeng
12:40
Lunch
Lunch
12:40 - 14:00
Room: Letitia Obeng
14:00
Bright Radiation Sources Driven by Ultrafast High-Intensity Lasers and Applications
-
Song Li
(
SIOM
)
Bright Radiation Sources Driven by Ultrafast High-Intensity Lasers and Applications
Song Li
(
SIOM
)
14:00 - 14:20
Room: Letitia Obeng
With the ongoing miniaturization and stabilization of laser wakefield accelerators (LWFA), tabletop X-ray sources based on such accelerators have shown great potential. Among them, Betatron radiation sources driven by ultrafast, high-intensity lasers feature micrometer-scale source size, femtosecond pulse duration, milliradian-scale divergence, and broadband spectra extending to tens of keV. These characteristics make them highly suitable for high-contrast imaging of microstructures, diagnostics of high-energy-density states in inertial confinement fusion (ICF), and ultrafast dynamic studies in multidisciplinary research. This presentation will showcase the recent development of a high-brightness Betatron hard X-ray source platform at the Shanghai Institute of Optics and Fine Mechanics (SIOM), Chinese Academy of Sciences. In particular, we report on Betatron sources driven by two high-power laser systems—a 1 PW/0.1Hz laser system at Shanghai Superintense Ultrafast Laser Facility (SULF) and a 200 TW/1 Hz laser—achieving critical energies in the range of 15–86 keV and photon yields exceeding 1010 photons per shot. We further demonstrate their application in X-ray phase-contrast imaging.
14:20
Wakefield Excitation in Carbon Nanotubes and Graphene Layers: Hydrodynamic Approach and PIC Simulations
-
Pablo Martín-Luna
(
IFIC( CSIC-UV)
)
Wakefield Excitation in Carbon Nanotubes and Graphene Layers: Hydrodynamic Approach and PIC Simulations
Pablo Martín-Luna
(
IFIC( CSIC-UV)
)
14:20 - 14:40
Room: Letitia Obeng
Charged particles traversing carbon-based nanostructures can trigger electromagnetic (plasmonic) modes through the collective excitation of surface electron gases. This phenomenon presents a promising avenue for achieving ultra-high particle acceleration gradients. Plasmonic excitations can be explored using both analytical models and particle-based simulations. In this work, we first revisit the theoretical framework based on a linearized hydrodynamic model describing a point charge moving along carbon nanotubes and graphene layers. Within this model, surface-confined electrons are treated as a two-dimensional plasma, with additional momentum contributions arising from the solid-state characteristics of the electron gas. We then compare the plasmonic responses predicted by the hydrodynamic model with those obtained via Particle-in-Cell (PIC) simulations. Finally, we conduct a detailed analysis to assess the similarities, differences, and limitations of both approaches.
14:40
Fine-tuning objective functions for Bayesian optimization of LWFA-accelerated electrons in nanostructured CNT targets
-
Alexandre Bonatto
(
Universidade Federal de Ciências da Saúde de Porto Alegre
)
Fine-tuning objective functions for Bayesian optimization of LWFA-accelerated electrons in nanostructured CNT targets
Alexandre Bonatto
(
Universidade Federal de Ciências da Saúde de Porto Alegre
)
14:40 - 15:00
Room: Letitia Obeng
Nanostructured materials composed of alternating layers of two-dimensional carbon structures and empty or low-density regions have emerged as promising targets for compact, ultra-high gradient electron acceleration via LWFA. As an intense laser pulse propagates through these gaps, the carbon atoms at their boundaries are ionized, filling the voids with high-density electron plasmas capable of sustaining accelerating gradients on the order of TeV/m. Consequently, few-micrometer-long targets can generate electron bunches carrying charges of hundreds of pico-coulombs and energies of several tens of MeV. The performance of such accelerators -- in terms of beam energy, charge, and quality -- depends sensitively on multiple parameters, including laser intensity, pulse duration, and target geometry. In this work, Bayesian optimization is applied to particle-in-cell simulations of concentric cylindrical-shell targets separated by vacuum gaps, aiming to identify configurations that favor edge and bubble-like self-injection of electrons for LWFA acceleration. The simulations are conducted with the FBPIC code, and Optimas is employed as the Bayesian optimization framework. Different formulations of multi-objective functions are evaluated and compared, and preliminary results reveal how these formulations affect the acceleration process and the resulting beam properties.
15:00
Coffee break
Coffee break
15:00 - 15:30
Room: Letitia Obeng
15:30
Theoretical, numerical and experimental potentials and opportunities
Theoretical, numerical and experimental potentials and opportunities
15:30 - 16:30
Room: Letitia Obeng
16:30
Coffee break
Coffee break
16:30 - 17:00
Room: Letitia Obeng
17:00
Invited talk
-
Toshiki Tajima
(
UCI
)
Invited talk
Toshiki Tajima
(
UCI
)
17:00 - 17:50
Room: Letitia Obeng
19:00
Dinner
Dinner
19:00 - 21:00
Friday, 7 November 2025
09:30
The NanoAc Collaboration: Toward a Proof-of-Principle for Laser Wakefield Acceleration in Nanostructured Solid-State Plasma
-
Javier Resta López
(
ICMUV-University of Valencia
)
The NanoAc Collaboration: Toward a Proof-of-Principle for Laser Wakefield Acceleration in Nanostructured Solid-State Plasma
Javier Resta López
(
ICMUV-University of Valencia
)
09:30 - 10:00
Room: Letitia Obeng
Solid-state plasma wakefield acceleration has recently attracted attention as a novel method for achieving unprecedented ultra-high acceleration gradients on the order of 1 TV/m or beyond. In this context, recent advancements in nanofabrication techniques have opened up the possibility of creating structured plasmas with tailored properties. For instance, the utilization of carbon nanotube (CNT) bundles holds great potential for generating stable plasmas with electron densities reaching as high as 10^24 cm-3, i.e., orders of magnitude higher than conventional gaseous plasmas. As part of a new collaborative effort called NanoAc, we have conducted Particle-In-Cell (PIC) simulations to investigate laser wakefield acceleration in nanostructured solid-state plasmas based on CNT arrays. Our results confirm the attainment of wakefields at the TV/m scale. Additionally, we observed self-injection, sub-femtosecond bunch formation, and electron acceleration in micrometre-scale targets, yielding kinetic energies of ~10 MeV. These findings open up promising possibilities to design novel ultra-compact accelerators and radiation sources. In this contribution, we present a summary of the work carried out by the NanoAc collaboration to date and discuss the preparation of future experimental tests in existing laser facilities.
10:00
Current status of FEBE laser and experimental opportunities
-
Lewis Reid
(
ASTeC, STFC
)
Current status of FEBE laser and experimental opportunities
Lewis Reid
(
ASTeC, STFC
)
10:00 - 10:30
Room: Letitia Obeng
10:30
All-optical source size and emittance measurements of laser-accelerated electron beams
-
Daniel Seipt
(
HIJ/GSI
)
All-optical source size and emittance measurements of laser-accelerated electron beams
Daniel Seipt
(
HIJ/GSI
)
10:30 - 11:00
Room: Letitia Obeng
Recent developments in ultra-low emittance electron beam generation offer compact, high-quality particle sources for future high-energy physics and free-electron laser applications. Measuring such excellent emittances poses a significant challenge. Here we present a new, laser-based technique which modulates the electron phase-space ponderomotively, achieving sub-0.1 mm mrad emittance resolution. We report the first experimental validation of this approach using a laser wakefield accelerator. Our results are in agreement with emittance and source size values of prior studies using different methods such as quadrupole scans. Additionally, we demonstrate that the "laser-grating" method provides upper limits on emittance and source size, even under conditions of low signal-to-noise ratio and uncertainties in laser-grating parameters.
11:00
Coffee break
Coffee break
11:00 - 11:30
Room: Letitia Obeng
11:30
High-quality particle and radiation sources from laser peeler regime
-
Xiaofei Shen
(
PKU
)
High-quality particle and radiation sources from laser peeler regime
Xiaofei Shen
(
PKU
)
11:30 - 12:00
Room: Letitia Obeng
Laser-based particle acceleration is a promising candidate for next-generation accelerators and radiation sources. However, currently, the laser-accelerated ion beams and radiations have limitations in peak energy, flux, energy spread, etc. In this talk, I shall report a novel method to overcome these limitations by irradiating the edge of a microtape with available femtosecond lasers, called laser peeler regime [1-4]. As the laser pulse sweeps along the tape, it excites a strong surface plasma wave, which accelerates tens of pC electrons to superponderomotive energies [1,5]. While acceleration, these electrons undergo transverse betatron oscillations, leading to emission of hard x-rays. On the other hand, when these high space charge electrons are injected into the accelerating region, protons are accelerated and bunched simultaneously, leading to a monoenergetic proton spectrum. Our 3D PIC simulations demonstrate that a monoenergetic proton beam with peak energy > 100 MeV and energy spread about 1% can be stably achieved [1], whilst emitting bright x-rays [4]. References: [1] X. F. Shen, et al., Phys. Rev. X 11, 041002 (2021); [2] X. F. Shen, et al., Quantum Electronics 51, 833 (2021); [3] X. F. Shen, et al., Plasma Phys. Control. Fusion 65, 034005 (2023); [4] X. F. Shen, et al., Commun. Phys. 7, 84 (2024); [5] A. McCay, et al., Phys. Rev. Lett. 135, 145001 (2025).
12:00
Laser-driven superior ion acceleration in relativistically transparent plasma via laser front steepening
-
Bin Liu
(
Guangdong Institute of Laser Plasma Accelerator Technology, Guangzhou, China
)
Laser-driven superior ion acceleration in relativistically transparent plasma via laser front steepening
Bin Liu
(
Guangdong Institute of Laser Plasma Accelerator Technology, Guangzhou, China
)
12:00 - 12:30
Room: Letitia Obeng
Laser-driven ion acceleration in plasma is an active topic of research. Various acceleration mechanisms have been investigated. Recently, with the fast development of petawatt laser technology, laser ion acceleration in near-critical relativistically transparent (NCRT) plasma has attracted much attention. Nanomaterial targets offer one of the most promising approaches for generating NCRT plasma. A petawatt laser pulse can make an initially over- but still near-critical plasma relativistically transparent and propagate in it. At the laser front, the laser radiation pressure piles up background electrons, generating a strong charge-separation field which is localized and comoving with the laser pulse. Basically, ion acceleration in the charge-separation field operates on principles analogous to electron acceleration in laser wakefield in dilute plasma [1,2]. However, as the plasma density increases, a new challenge arises. In dilute plasma, the laser plasma interaction mainly follows the linear dispersion relation and thus the phase velocity of the wakefield is dominated by the normalized plasma density. In a NCRT plasma, however, the laser-plasma interaction becomes highly nonlinear, and the propagation velocity of the laser-driven charge-separation field is governed by the balance between the electrostatic pressure and the laser radiation pressure, making it depend not only on the plasma density but also on the laser amplitude at the front [3,4]. This can result in an inertial force in the frame comoving with the charge-separation field, which can prevent the trapping of background ions or disrupt the acceleration of already trapped ions, especially when achieving high energy acceleration. In this talk we show that this can be overcome by employing a buffering underdense plasma to steepen the leading edge of the laser pulse in advance. This can lead to a superior ion acceleration process known as ion wave breaking acceleration [5] which is promising in producing quasi-mono-energetic and collimated ion beams. [1] B. Liu, J. Meyer-ter-Vehn, and H. Ruhl, Physics of Plasmas 25, 103117 (2018). [2] B. Liu, M. Shi, M. Zepf, B. Lei, and D. Seipt, Physical Review Letters 129, 274801 (2022). [3] B. Liu, J. Meyer-ter-Vehn, H. Ruhl, and M. Zepf, Plasma Physics and Controlled Fusion 62, 085014 (2020). [4] B. Liu, B. Lei, Y. Gao, M. Wen, K. Zhu, Plasma Physics and Controlled Fusion 66, 115004 (2024). [5] B. Liu, J. Meyer-ter-Vehn, K.-U. Bamberg, W. J. Ma, J. Liu, X. T. He, X. Q. Yan, and H. Ruhl, Physical Review Accelerators and Beams 19, 073401 (2016).
12:30
Diagnostic techniques in plasma-based accelerators
-
Hao Zhang
(
UOL/CI
)
Diagnostic techniques in plasma-based accelerators
Hao Zhang
(
UOL/CI
)
12:30 - 12:50
Room: Letitia Obeng
12:50
Lunch
Lunch
12:50 - 14:10
Room: Letitia Obeng
14:10
Laser wakefield acceleration in carbon nanotube bundles
-
Jiaqi Zhang
(
University of Manchester
)
Laser wakefield acceleration in carbon nanotube bundles
Jiaqi Zhang
(
University of Manchester
)
14:10 - 14:30
Room: Letitia Obeng
Laser wakefield acceleration (LWFA) can produce gradients of tens to hundreds of GV/m, greatly reducing accelerator size and cost. Carbon nanotube (CNT) bundles, featuring high plasma density (>10 cm ), tunable effective density, and empty channels that enable laser propagation, have attracted interest as solid-state plasma sources. Previous studies have suggested that CNT-based structures can increase acceleration gradients to the TV/m range, making them promising for compact radiation sources. In this work, we model a hollow solid-state plasma channel composed of CNT bundles. A 2 PW laser from the ELI-ALPS High-Field Laser facility is injected into the channel, where self-injected electrons at the nC scale are trapped and accelerated in a TV/m gradient, as shown by particle-in-cell (PIC) simulations with WarpX. We determined the effective plasma density and laser configurations through parameter optimisation with uniform CNTs. Using CNT bundles, we then achieved unprecedented beam quality: >2 nC charge, >100 MeV mean energy, <5% energy spread, and <10 mm·mrad emittance, by tuning the filling factor, bundle diameter, and gap size. Related acceleration processes are also demonstrated.
14:30
Analytical, Computational, and Experimental Study of Discharge Plasma Capillaries for Laser Plasma Wakefield Acceleration
-
Mostafa Behtouei
(
Centro de Láseres Pulsados (CLPU)
)
Analytical, Computational, and Experimental Study of Discharge Plasma Capillaries for Laser Plasma Wakefield Acceleration
Mostafa Behtouei
(
Centro de Láseres Pulsados (CLPU)
)
14:30 - 14:50
Room: Letitia Obeng
Laser Plasma Wakefield Acceleration (LPWA) is a promising way to achieve ultra-high accelerating gradients, relying on plasma channels to guide intense laser pulses over long distances. In this study, we explore discharge plasma capillaries as a potential solution for stable laser guiding and precise control of plasma density. We start by using Computational Fluid Dynamics (CFD) simulations to understand how the neutral gas distributes inside capillaries of different shapes before ionization, and then examine how plasma channels form, taking into account discharge settings, capillary geometry, and gas pressure. At the same time, we are developing an experimental setup to study the plasma directly through Stark broadening spectroscopy. By combining analytical, computational and experimental approaches, this work provides a foundation for developing optimized plasma channels for LPWA.
14:50
Coffee break
Coffee break
14:50 - 15:20
Room: Letitia Obeng
15:20
Collaboration and opportunities
Collaboration and opportunities
15:20 - 16:10
Room: Letitia Obeng
Contributions
15:20
Contributed talk
16:10
16:10 - 16:20
Room: Letitia Obeng