Laser technology continues to advance and contribute to nuclear physics research and applications, and it has the promise of playing an ever larger role. Ultrashort-pulse lasers can produce secondary radiation, including energetic particles and photons that can initiate nuclear reactions and probe nuclear states. Laser-driven implosion facilities also create conditions relevant for nuclear...
The Laser-Driven Neutron Source (LDNS), a novel approach to neutron generation, has attracted significant attention due to its capability to produce neutron pulses with ultra-short duration and high flux [1].
In this presentation, we introduce our recent progress on high-flux neutron generation [1] and single-shot neutron resonance spectroscopy using LDNS [2]. In our experiments, the petawatt...
Laser-driven ion sources of picosecond duration enable new frontiers in the exploration of proton radiolysis, ultrafast atomic dynamics, and nanostructured dose distribution, providing unprecedented insights into how energy deposition influences chemical and structural change, with broad implications in medicine, chemistry, and materials science. However, ions produced by intense laser...
Laser-driven ion acceleration has attracted significant research interest due to its ability to generate high-flux pulsed ions. Applications such as compact neutron sources [1] have already been demonstrated. However, for further applications such as cancer therapy and nuclear physics studies, quasi-monoenergetic ions with controllable energy are highly desirable.
In this presentation, we...
Neutron beams have various applications, ranging from nuclear physics to medical and security. Laser-driven neutron sources are a compact technique for generating neutron beams from laser-accelerated particles. A high-power laser is directed at a target (pitcher), where it produces an ion beam with target normal sheath acceleration (TNSA). Subsequently, the ion beam propagates towards a second...
The quest for an optical nuclear frequency standard, the ‘nuclear clock’ based on the elusive and uniquely low-energetic ‘thorium isomer’ $^{229m}$Th, has increasingly triggered experimental and theoretical research activities in numerous groups worldwide in the last decade. Today’s most precise timekeeping is based on optical atomic clocks.However, those could potentially be outperformed by a...
Electron dynamics play a fundamental role in the behavior of matter and underpin many essential natural phenomena. Notably, these processes are also crucial to fundamental mechanisms in nuclear physics. Nuclear states can exchange energy with surrounding electrons, and nucleus–electron couplings drive a wide range of nuclear decay processes that are of significant scientific and technological...
Nuclear physics studies atomic nuclei and their constituents and interactions. While not particularly spectacular from nuclear physics point of view, the photo-excitation of low-lying nuclear states opens the new field of nuclear quantum optics and may bring substantial progress in the field of metrology. These developments aim to exploit the fact that nuclei are very clean quantum systems,...
Photon-induced fission provides a mechanism for studying fission stimulated via the theoretically well understood electromagnetic interaction. The lack of hadronic processes in the entrance channel limit the angular momentum transferred to the excited nucleus prior to fission to typically 1 unit, i.e. either an electric or magnetic dipole excitation. We have performed extensive double...
Measurements of photofission cross sections utilizing quasimonoenergetic $\gamma$-ray beams historically rely on neutron detection, producing photoneutron data that must be sorted into the relevant reaction channels: ($\gamma$,n), ($\gamma$,2n), ($\gamma$,3n), and ($\gamma$,f). This deconvolution is a model-dependent process that has led to longstanding systematic discrepancies in photonuclear...
Electromagnetic excitations (primarily M1 and E2) of heavy deformed nuclei, such as $^{154}$Sm, $^{166}$Er, etc., with excitation energies $E_x=2-4$ MeV will be discussed in terms of the most advanced Monte Carlo Shell Model (MCSM) calculations. For M1 excitations, the recent MCSM result indicates M1 spectrum very close to experimental ones, but we also see strong spin contributions. Such...
The availability of nuclear structure information on transuranium actinides has a direct impact on the modeling of stellar nucleosynthesis and supports isotope-selective material inspection via photonuclear reactions. However, experimental data in this region are still scarce.
The first nuclear resonance fluorescence (NRF) experiment on $^{242}$Pu was conducted at the S-DALINAC at TU...
Narrow-bandwidth, high-brilliance, tunable, MeV-class, x-ray sources fundamentally enable nuclear spectroscopy and applications in ways that are not possible with existing bremsstrahlung based emitters.
This presentation will review the motivation for creation of such sources based on laser-Compton scattering, outline how a distributed charge Compton scattering (DCCS) architecture can...
Compton sources based on free-electron lasers (FELs) have a long history and have been successfully implemented for practical use, notably as gamma-ray sources utilizing storage rings. A prominent example is the High Intensity Gamma-ray Source (HIGS) facility at Duke University, which delivers tunable gamma-ray beams in the energy range of 1–100 MeV for nuclear physics experiments.
In this...
Laser-driven ion acceleration has gained significant attention as a next-generation acceleration technology, offering key advantages such as compactness, high accelerating electric fields, and short pulse durations. In this study, we aim to realize a novel accelerator system called the Quantum Scalpel, which combines a laser-driven heavy ion injector with a superconducting synchrotron...
Accelerator-driven X-ray sources had a profound impact on the applications of the Mössbauer effect in all natural sciences. The enormous brilliance of X-rays delivered by these sources enabled access to smallest amounts of materials under extreme conditions and allowed for studies with time resolution and polarization sensitivity that were virtually impossible in the lab. In this way it was...
Probing resonances in Mössbauer nuclei with x-rays or γ-rays is widely used to study structure and dynamics of matter with a remarkably high energy resolution. So far, most experiments use radioactive or synchrotron radiation sources. In the past few years, self-seeded X-ray free electron lasers have become available, which provide qualitatively new conditions for studying interactions of the...
The advent of quantum sensing x-ray microcalorimeters such as Transition Edge Sensors (TESs) [1] has created exciting new opportunities to push the limits of precision physics in the hard x-ray domain. Thanks to the factor of 50 improvement in energy resolution offered by TESs over high-purity germanium [2, 3], and their high efficiency compared to crystal spectrometers [4], anti-protonic...
One of the uncharted territories in nuclear physics concerns a thrilling frontier in the study of systems where particles interact with relatively low-energy (< 20 MeV) yet extraordinarily high-intensity fields. In such environments, multi-particle processes rival and surpass traditional one-to-one interactions, opening the door to groundbreaking discoveries.
Here, we focus on a new scheme...
I will present selected results on nuclear giant and pygmy resonances at zero and finite temperatures, based on recent advancements in nuclear many-body theory [1-6]. The theory will be compactly introduced in the most general quantum field theory formalism with only the bare fermionic interaction input. A special focus will be placed on the emergent scale of the quasiparticle-vibration...
Random Matrix Theory provides a comprehensive framework for the description of complex, chaotic quantum systems [1,2]. It is exploited across various domains of physics as for instance in the statistical treatment of nuclear reactions within the Hauser-Feshbach formalism [3]. One important aspect in the practical application of Hauser-Feshbach codes is the fluctuation property of partial...
The $\gamma$-ray beam under construction at the ELI-NP facility is projected to provide users with high-energy, high-intensity and narrow bandwidth photon beams for nuclear structure studies. Two major topics that can be studied at such a facility, with the almost complete selectivity of electromagnetic probes, are high-precision measurements of nuclear $J^{P}=1^{-}$ level densities and the...
Driven by recent advances in the understanding of coexisting shapes in the even-even Ni isotopes, the structure of neighboring $^{68}$Zn was investigated using nuclear resonance fluorescence. Low-spin levels were excited using linearly polarized photon beams at energies ranging from 3 MeV to the particle threshold using the High Intensity $\gamma$-Ray Source (HI$\gamma$S). In addition,...
Intense lasers enable a range of schemes for generating high-energy particle beams in university-scale laboratories. In direct laser acceleration (DLA), the leading edge of the laser pulse ionizes the target material, forming a positively charged plasma channel that traps and accelerates electrons. DLA offers exceptional conversion efficiency — often exceeding 20% — making it highly suitable...
Excitation of long-lived states in bromine nuclei using a table-top laser-plasma accelerator providing pulsed (<100 fs) electron beams provided a sensitive probe of gamma strength and level densities in the nuclear quasicontinuum, and may indicate angular momentum coupling through electron-nuclear interactions. Solid-density LaBr$_{3}$ active targets absorb real and virtual photons up to 35 ±...
Broadband MeV to multi-GeV 10 PW laser-driven gamma-rays generation, characterization and possible applications
V. Lelasseux1, P. Ghenuche$^1$, V.L.J. Phung$^1$, H. Ahmed$^2$, D.L. Balabanski$^1$, M.O. Cernaianu$^1$, D. Choudhury$^{1,3}$, S. Corde$^{4,5}$, F. D’Souza$^{1,6}$, M. Gugiu$^1$, V. Iancu$^1$, S. Krishnamurty$^7$, I. Kargapolov$^7$, L. Lancia$^8$, G. Lorusso$^9$, A. Leblanc$^4$,...
The Extreme Light Infrastructure – Nuclear Physics (ELI-NP) has established itself as a world-leading facility by operating the first dual-arm 10 petawatt (PW) laser system, HPLS, which serves as a cornerstone for experimental nuclear photonics research. In 2024 alone, ELI-NP achieved 67 operational weeks of beam delivery for users, including 30 weeks at full 10 PW output at a 1 shot/minute...
We will present results aimed at enabling a novel dual (neutron and x-ray) interrogation method, based on ultra-intense lasers irradiating solid targets. The objective is to
perform dense material probing, while also supporting imaging of high speed events. The concept is to produce both a bright X-ray source
appropriate for high-resolution radiography from thin primary (pitcher) targets...
The giant dipole resonance (GDR) of atomic nuclei dominates their response to an oscillating electromagnetic radiation field. It represents the archetype of a collective nuclear mode. It is particle unbound and decays predominantly by particle emission. Its (small) probability for internal decay by gamma-ray emission is proportional to the maximum of its photon absorption cross section.
Our...
I review the theory side of the synergetic international effort of experimentalists and theorists in Compton scattering on one- and few-nucleon systems. It probes the symmetries and strengths of nucleonic and nuclear interactions and relates them to lattice-QCD computations of fundamental hadronic properties. The polarisabilities parametrise the stiffness of charge distributions against...
The Compton@HIGS collaboration is embarking on a program of absolute differential cross-section measurements of elastic Compton scattering from 1H [1], 2H, 3He, and 4He [2,3] nuclei over a wide range of scattering angles at energies below the pion production threshold. Using a Chiral Effective Field Theory (𝜒EFT) framework [4], we can extract the electric and magnetic polarizabilities of...
For the first time, we succeeded in observing the $\gamma$-ray beam production via Compton scattering of X-rays at an electron storage ring. Compared with laser Compton scattering, the X-ray Compton scattering is attractive because $\gamma$-ray energies can be drastically increased approaching to the ring energy. We developed a new innovative $\gamma$-ray beam source at NewSUBARU, which is a 1...
The isovector giant dipole resonance (IVGDR) is one of the dominant excitations of the atomic nucleus. In addition to providing insights on nuclear structure, it is involved in many applications, such as in nuclear astrophysics. Characterizing the IVGDR over the nuclear chart is of fundamental importance, and experimental data in both stable and exotic nuclei provide cornerstones in the...
The PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project explores photo-nuclear reactions in light nuclei (A $<$ 60) through both experimental and theoretical studies. This research is particularly relevant to ultra-high-energy cosmic rays (UHECRs), where energy and mass loss primarily occur via electromagnetic interactions between nuclei and the...
Electromagnetic excitations are a unique probe to the internal structure of a nucleus. In this talk, nuclear electromagnetic responses are investigated using the ab initio coupled-cluster theory. We determine dipole response functions and electric dipole polarizabilities in both closed-shell nuclei and open-shell isotopes close to magicity, and discuss their evolution along isotopic...
Our understanding of the nuclear collective behaviour is not yet complete. There are elusive collective modes, and new types of probes, such as vortex photons, have been proposed as a means to access them. Vortex photons could enable the identification of isovector modes other than the Giant Dipole Resonance (GDR) and thus provide new information on the nuclear Equation of State (EoS). In this...
This presentation brings into focus $^{78,80}$Kr$(\gamma,\gamma’)$ cross section measurements carried out using real photons at the HIGS/TUNL facility. The overarching physics motivation for these experimental investigations is to advance knowledge on a forefront topic in nuclear astrophysics – the nucleosynthesis beyond Fe of the rarest stable isotopes naturally occurring on Earth (the origin...
The electric dipole response of the nucleus reveals important spectroscopic features of its structure and the mechanism of its interaction with external electromagnetic and hadronic fields. Here, we present new results on dipole strength distributions of direct and cascade transitions to GDR energies in neutron-excess nuclei from various mass ranges, obtained within a theoretical approach...
This work focuses on exploring the Pygmy Dipole Resonance (PDR) in the deformed $^{154}$Sm nucleus. The study employs the ($\vec{\gamma}$,$\vec{\gamma}^{\prime}$) reaction to probe dipole states in the energy range of 3.5$~$MeV to 7.05$~$MeV, approaching the neutron separation energy at 8$~$MeV. Measurements were conducted at the HI$\gamma$S facility of the Triangle Universities Nuclear...
Over the past decade the use of twisted photons to probe the properties of atomic and nuclear systems was considered both theoretically and experimentally [1-3]. Since the angular momentum is conserved in the transitions involving the electromagnetic radiation, it is convenient to consider the states of photons with well-defined total angular momentum. Therefore in the first part we discuss...
Photon vortices are light carrying large orbital angular momentum (OAM) at the quantum level [1]. They can be described by Laguerre-Gaussian or Bessel wave functions, which are waves that are eigenstates of the total angular momentum along their propagation direction. Unlike plane-wave photons, photon vortices interact differently with materials because their OAM affects the way they transfer...
In the UVSOR synchrotron facility, gamma rays with a maximum energy of 6.6 MeV are generated by 90-degree inverse Compton scattering (ICS) between a 750 MeV electron beam and a Ti:Sa laser with a wavelength of 800 nm. The gamma rays are used for atomic-scale defect analysis using gamma-ray-induced positron annihilation spectroscopy [1] and for evaluation of polarized gamma-ray detectors. The...
The Turkish Accelerator and Radiation Laboratory (TARLA) is a user facility based on a superconducting linear accelerator designed to reach 40 MeV and 1.6 mA. TARLA will be equipped with two beamlines: one for bremsstrahlung and the other for a free-electron laser. Currently, the first accelerating section, providing 20 MeV acceleration, is completed, while the second, for 40 MeV, is under...
Recent advancements in laser-based particle acceleration technologies have opened new possibilities for conducting nuclear reaction studies at tabletop scales. Among various laser-based nuclear reaction experiments, this research focuses on the pitcher-catcher configuration utilizing laser-driven ion beams.
Typically, nuclear reaction rates in equilibrium plasmas, such as astrophysical...
This work focuses on the experimental characterization of a neutron source driven by the high-energy (between 300 and 700 J), short pulse (700 fs) LMJ-PETAL facility. For this purpose, we have developed two experimental platforms, both operating in a pitcher-catcher configuration [1], but using either a solid target or a gas plasma to generate the primary high-energy particle beam.
Our first...
Low energy neutron (thermal neutron) sources are widely used in various fields such as neutron radiography, neutron diffraction, and Boron Neutron Capture Therapy (BNCT). Spin-polarized neutrons are also considered as one of the next generation quantum sources, enabling analysis of magnetic structures of materials. Laser-driven neutron sources are considered promising due to their point source...
Quantum field theory predicts a nonlinear response of the vacuum to strong electromagnetic fields of macroscopic extent. This fundamental tenet has remained experimentally challenging and is yet to be tested in the laboratory. A particularly distinct signature of the resulting optical activity of the quantum vacuum is vacuum birefringence manifesting itself in a polarization-flipped signal...
Biblis is the site of a former 2.6 GW fission power plant facility, currently under decommission. In 2025, by the invitation of the Hessian government, a round table meeting took place on site, involving partners from industry, academia, and research laboratories to sign a memorandum of understanding to repurpose the site for a future research campus on laser fusion energy.
As a first...
Institut für Kernphysik, Fachbereich Physik, Technische Universität Darmstadt
Technische Universität Darmstadt is operating the first performant superconducting multi-turn energy recovery linac (ERL) [1]: S-DALINAC. With this technology, the kinetic energy of accelerated electron bunches can be recycled after their usage in a dedicated interaction. The recycled energy is used to accelerate...
Experimental data on tritium-induced nuclear reactions involving neutron-rich light nuclei such as 6He, 8Li, and 11Be remain scarce, despite their critical importance in nuclear astrophysics. These nuclei play a pivotal role in the rapid neutron capture process (r-process), acting as seed nuclei that influence nucleosynthesis pathways beyond the A=5 and A=8 mass gaps. Their relevance covers...
In contrast with the other light elements, the Li-7 measured abundance is 3-4 times lower than expected from the Big Bang Nucleosynthesis predictions. This fact is known as the “cosmological Li problem” and a better understanding of the disagreement may be achieved by studying the reactions which are leading to the Li-7 production and destruction. The $^3$H(α,γ)$^7$Li reaction contributes to...
With the low angular-momentum transfer in the inelastic scattering of real photons, the photo-excited states often have relevance also for other nuclear processes, in particular weak processes. For example, scattering of neutrinos off atomic nuclei, governed by the weak force, can predominantly excite magnetic-dipole excitations, which subsequently decay via gamma or particle emission,...
Structural effects in the lightest stable nuclei were the first to be studied experimentally. Early research focused on isospin mixing, properties of isospin multiplets, and α clustering. Recently, the existing experimental data for the γ decay of the stable N = Z doubly odd nuclei and the β decay of the corresponding isospin multiplets were reviewed [1]. Nowadays, with the advances in ab...
The Pygmy Dipole Resonance (PDR) is a low-energy excitation mode contributing to the electric dipole response in atomic nuclei. Despite significant theoretical and experimental progress over the past decades [1-3], its precise nature and origin are still under investigation. To clarify these open questions, systematic studies along isotopic and isotonic chains are essential. Such research has...
The major advances in laser-plasma acceleration techniques for charged particle beams have generated significant interest in the development of laser-based solutions for proton beam therapy [1, 2]. The particularities of laser-plasma accelerated ion beams that could benefit the biomedical field feature ultra-short pulse durations, down to tens of picoseconds, and high fluxes, with peak values...
In recent years, there has been a growing interest in laser-driven ion accelerators as a potential alternative to conventional accelerators [1]. A particularly promising application is the production of radionuclides relevant for medical diagnosis, such as $^{11}$C for PET imaging. Typically, the production of these nuclides is centralised at cyclotrons, reducing the number of facilities...
Interferometric X-ray imaging based on refraction (differential phase contrast) can be much more sensitive to small soft tissue lesions than conventional X-ray imaging based on absorption, being a potential game changer for medical diagnostics. In addition, because interferometry uses the transmitted radiation, the radiation dose can be reduced by imaging at higher X-ray energy, where the...
Photocathodes based on the III-V seminconductor GaAs are used as photo-electron sources to supply spin-polarized electron beams for accelerator applications. In order to achieve a sufficient electron yield, a thin surface layer of cesium combined with an oxidant is applied onto the cathode surface. This process is called the cathode activation and is typically done manually by an experienced...
The rapid development of high-power laser systems in recent decades has sparked significant interest in laser-driven ion acceleration, offering promising characteristics such as high brightness, ultrashort pulse duration, and high particle energies. However, the practical use of laser-accelerated ion beams remains challenging due to their large energy spread and high angular divergence,...
Nuclear reactions of astrophysical interest often concern unstable or even exotic species for which no experimental data exist. Although significant efforts have been devoted in the past decades, experimental information only covers a minute fraction of the data set required for nuclear astrophysics. Moreover, the energy range for which experimental data is available is restricted to the small...
High Purity Germanium (HPGe) detectors are very important tools in nuclear and particle physics, primarily due to their low energy thresholds and exceptional energy resolution, which enables precise measurements across a broad energy spectrum. This study aims to comprehensively characterize the performance of four gamma-ray detectors: two n-type HPGe detectors and two Clover detectors, which...
This work explores the stabilization of key parameters in dual-arm femtosecond laser systems, focusing on improving spatio-temporal control and synchronization to achieve peak powers above 10 PW. In the High-Power Laser System (HPLS) at ELI-NP, pulse energy, spectrum, and temporal "jitter" were analyzed to identify sources of instability and improve overall performance. The ongoing upgrade of...
High-precision experimental data on photon-induced reactions provide an important contribution to the pursuit of a complete microscopic description of the fission process due to their selectivity on excitation of low multipolarity. Unique information can be extracted by using mono-chromatic polarized photons in the entrance channel allowing a determination of transition states through which...
We present a data-driven analysis of dipole strength functions across the nuclear chart, employing an artificial neural network to model and predict nuclear dipole responses. We train the network on a dataset of experimentally measured dipole strength functions for 216 different nuclei. To assess its predictive capability, we test the trained model on an additional set of 10 new nuclei, where...
Dipole polarizabilities are one of several complementary ways to put more narrow constraints on the symmetry energy slope parameter of the nuclear equation of state. Also, precise measurements of dipole polarizabilities present a sensitive benchmark for modern nuclear theory calculations.
In order to derive experimental dipole polarizabilities, nuclear photoabsorption cross sections are...
Electromagnetic response of nuclei plays an important probe in the understanding of nuclear structure. This quantity is also very crucial in the context of nucleosynthesis such as in r-process calculations. R-process studies require calculations of many nuclei and typically the response is extracted by using linear response approaches such as quasiparticle random phase approximation (QRPA)....
Understanding the origin of heavy chemical elements in the Universe remains a fundamental challenge. One of the primary mechanisms for forming such heavy nuclei is the rapid neutron capture process (r-process), which can occur during neutron star mergers [1]. In this process, neutrons are captured at high temperatures, leading to the formation of very neutron-rich nuclei.
In the actinide...
A series of nuclear resonance fluorescence experiments was conducted with bremsstrahlung at $\gamma$ELBE and a quasi-monoenergetic, polarized photon source at HI$\gamma$S.
The acquired experimental data allows for a model-independent determination of the dipole response of the most neutron-rich stable zinc isotope, $^{70}$Zn, which will aid in a better understanding of collective nuclear...
Experimental evidence of the inverse of internal conversion, nuclear excitation by electron capture (NEEC), continues to elude nuclear and plasma physicists alike. Following the reported observation of NEEC in Nature, 2018, using $^{93m}$Mo[1], and its subsequent theoretical disagreement [2], there has been heightened interest in the nuclear excitation mechanism.
Induction and isolation of...
The giant dipole resonance (GDR) represents one of the most fundamental nuclear excitations and dominates the photoresponse of virtually all nuclei. Its geometrical viewing is an isovector oscillation of the proton against the neutron body. This model also provides predictions for the $\gamma$-decay behavior of the GDR in elastic photon and $2^+_1$ Raman scattering reactions.
To rigorously...
The rare-earth region of the nuclear chart is one of the most thoroughly explored in terms of quadrupole deformation, providing a valuable benchmark for studying nuclear structure and collectivity. Two key observables in this context are the energy ratio $R_{4/2}$ and the reduced transition probability $B(E2; 2_1^+ \to 0_1^+)$, which serve as indicators for nuclear structure. Notably, nuclei...
Systematic studies along isotopic and isotonic chains are essential for understanding the characteristics of the low-lying dipole response in atomic nuclei. Such studies can provide valuable insights into the influence of factors such as shell structure and neutron excess on dipole strength. Since photons transfer only small angular momenta, real-photon scattering, commonly denoted as Nuclear...
Laser-based particle sources allow for investigating biological effects of radiation at high instantaneous dose rates. We have run two experiments including the irradiation of monolayer cell cultures at total dose values of 3-12 Gy.
The first one, at the Laser Laboratory for Acceleration and Applications (L2A2), makes use of an X-ray source driven by a 35 fs pulsed laser with 1 mJ pulse...
Photonuclear reactions are a powerful tool to probe the quantum structure of the atomic nucleus by inducing single-particle and collective excitations [1], and also played a significant role in the first moments of our universe or later in stellar nucleosynthesis processes [2]. These reactions are also of great interest because of their many societal applications, such as national security,...
The r-process path of cosmic nucleosynthesis is expected to proceed partly along the $N = 126$ neutron shell closure where it contributes to the third r-process peak [1]. Improved microscopic understanding of cosmic nucleosynthesis calls for more precise and complete data on neutron-rich nuclei in the mass region around the doubly-closed shell nucleus $^{208}$Pb that serve to constrain...
The performance of three different target types—glass slide, polymer film, and liquid sheet—was evaluated for use in plasma mirror Frequency Resolved Optical Gating (PM-FROG) diagnostic of chirped near-infrared laser pulses in the 1–8 ps range. The measurements were conducted at the High Power Laser System (HPLS) of ELI-NP, employing both arms of the laser system in a pump-probe configuration....
Spatio-Temporal Couplings (STC) of ultra-intense laser pulses can significantly impact
relativistic particle acceleration or radiation production, relevant for nuclear photonics applications.
This STC experimental study covers the analysis of residual and induced
spatio-temporal distortions generated with a fs laser oscillator. Complementary, propagation simulations
using real data from...
Laser-accelerated ions typically exhibit an exponential energy spectrum up to a characteristic cut-off energy, which is a signature of target normal sheath acceleration (TNSA) [1]. However, many applications, such as proton therapy [2] or the fast ignition concept in inertial confinement fusion [3] benefit from well defined spectral shapes.
By introducing multiple ion species into the...
Neutral beam injection (NBI) is an established heating method on many existing magnetic confinement fusion devices. Most currently operated NBI systems create neutral Hydrogen, Deuterium, or even Tritium [1] by neutralizing positive or negative ion beams in a gas neutralizer (GN). For ITER a beam energy of 1MeV Deuterium was chosen. It was found that the neutralization yield of positive ions...
This study aims at understanding the dependence of the E1 strength in the transition region from vibrational to rotational nuclei. The chosen method of study is the Nuclear Resonance Fluorescence method, a two-step photonuclear process which consists of the absorption of a photon and the subsequent resonant re-emission of gamma rays.
The experimental data has been acquired using the DHIPS...
In this study, the optimisation of the longitudinal density profile, thickness, and density gradient on the rear side of the gas target formed by a symmetrical and unsymmetrical shock nozzle for the acceleration of proton beams utilising high-repetition kHz lasers has been carried out.
Most of the laser-driven ion acceleration experiments are performed using PW-class lasers focused on the...
The Mössbauer effect allows recoilless resonant nuclear excitation through the interaction of nuclear states with the crystal lattice [1]. This enables energy exchange with vibrational modes (phonons), which can dress the nuclear transition and even allow resonant absorption at slightly detuned photon energies. This process is typically studied using nuclear inelastic scattering. While...
With the advancement of intense laser technology, nonlinear Compton scattering (NCS), in which multiple laser photons are absorbed and a single high energy photon is emitted, has been actively investigated to probe electron and photon dynamics in strong electromagnetic fields [1].
Taira et al. proposed, based on classical electrodynamics calculations, that NCS with circularly polarized...
Since the inception of laser science, one fundamental goal has always been increasing the intensity of laser pulses. One of the techniques used for achieving this goal is Self Phase Modulation (SPM), consisting of pulse propagation through nonlinear media and using nonlinear effects to broaden the spectrum, enabling better compression and shorter pulse lengths. In this presentation, I outline...
To support high-repetition-rate particle production for applications such as radioisotope production, hadron therapy or neutron production, liquid targets are being developed at ELI-NP. With increasing repetition-rates achieved by lasers, liquid targets must regenerate rapidly to ensure consistent interaction conditions. In this study, we investigated the regeneration dynamics of a water...
A new setup for Laser-Compton back-scattering has been installed at the S-DALINAC. Here, the laser beam and the electron beam of the S-DALINAC, both with a width of equal or less than 100 µm, must be stably superimposed over long periods of time. Three systems have been developed, implemented and interconnected to monitor and improve the transverse stability of the electron beam [1]: (i) A...
The advent of intense beams of quasi-monochromatic polarized photons from laser Compton backscattering in the MeV energy range has revolutionized the field of photonuclear reactions [1]. A fourth generation light source comprising laser Compton backscattering from a multi-turn energy-recovery electron linac (ERL) is considered the next technological step. Such a system has not been realized,...
Our research group has been studying isotope CT imaging using nuclear resonance fluorescence with energy-tunable gamma-ray beams generated by laser Compton scattering (LCS) and is currently working on simultaneous imaging of multiple isotopes and their quantitative evaluation. When an incident gamma-ray beam covers two different resonance energies of two nuclides, it is possible to obtain two...
Nanostructured targets can enhance the laser-matter interaction by coupling the laser pulse into the target, by volumetric heating, due to the increased surface area, leading to higher proton energy cut-off, yield, X-ray or gamma ray emission, and terabar pressure. However, enhanced coupling is highly dependent on the correlation of the target parameters to the laser pulse characteristics (as...
Nuclear physics has entered the era of high-precision studies. For light nuclei, modern theories of nuclear forces, such as chiral effective field theory ($\chi$EFT), predict selected electromagnetic transition rates to a few percent accuracy, where they are sensitive to effective two-body currents (2BC). Measurements of decay widths of a few percent or better allow us to test theories [1]. To...
Electron-capture rates on medium-heavy nuclei play a crucial role in the last stage of core-collapse supernovae of massive stars during the deleptonization process. While these rates are highly sensitive to their Gamow-Teller (GT) strength [1], their direct measurement remains experimentally challenging. As an isospin analogue, the isovector spin-flip M1 (IVSM1) response offers an alternative...
Laser-driven photon sources benefit from the inherently small source size and ultrashort duration, resulting in high brilliance beams. Different configurations based on laser-driven electron acceleration have been proposed so far in order to improve the laser-target energy coupling and obtain high energy and high photon flux sources. One method to enhance the number of radiating electrons is...
X-ray sources are of growing importance as a diagnostic tool for High Energy Density (HED) experiments and Inertial Confinement Fusion (ICF) studies as well as the upcoming FAIR facility in Darmstadt. For these applications, so-called x-ray backlighters must meet requirements regarding low divergence, small source size to achieve a sufficient imaging resolution and high brightness to overcome...
