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Optimization methodology for FLUKA simulations

• Maxim Andronic (LDED)

We introduce an optimisation methodology for maximising secondary particle and radiation yields from laser–plasma accelerators. The approach is demonstrated using the recently proposed pump- depletion–dominated laser wakefield acceleration regime [V. Horný et al., Phys. Rev. E 110,035202 (2024)] as a reference case. Particle-in-cell simulations of a 6 fs, 1.5 J laser pulse driving a plasma accelerator are coupled to FLUKA Monte Carlo modelling of a tungsten converter in a two-stage workflow. Systematic scans of plasma length and converter thickness are combined with three optimisation algorithms, bench-marked against a conventional grid search. The methodology improves both accuracy and computational efficiency, offering a robust framework for tuning secondary sources. For the reference configuration, we obtain peak values of 7.6 × 10^8 neutrons per shot (detected immediately behind the converter) and ∼0.49 J of total photon energy, highlighting strong prospects for high-repetition-rate operation.

Computational Tools For The Characterization of Electron Beams Generated via LWFA For A Muon Source

• Diana Catana (LDED)

Muon tomography has become in the last few years one of the most widely studied applications of Laser - Wakefield Acceleration (LWFA). In order to create a reliable muon source, we stabilized the electron beams energy gain to high-energies peaking between 6 and 8 GeV and integrated charge of hundreds of pC. To ensure the detection of muon beams, heavy shielding was installed. The detectors employed in the reconstruction of the muon beams were placed in 15 different positions. Here we present the computational tools we developed for the characterization of electron beams and a few preliminary results from the experimental campaign conducted at ELI-NP.

Dynamical Evolution of Ternary Particles from the Neck Region in the Fission of 236U

• Midhun Cherumukku (GDED)

For a long time, ternary particle emission in low-energy fission has suggested the presence of non-equilibrium dynamics within the neck at the time of scission. We report a microscopic framework that follows the time evolution of nucleon densities in the neck of the fissioning system during the transition from saddle to scission. The shape evolution is modeled using multi-dimensional Langevin dynamics on macroscopic--microscopic potentials, generated from two-centered shell-model calculations. The hot neck region is treated as a dilute nuclear medium, where proton and neutron densities are fixed by local chemical potentials and propagated dynamically. Exciton populations are formed within discretized neck cells, which evolve through a momentum-space coalescence mechanism. That drives cluster formation, followed by decay via pre-equilibrium emission. As a test case we have chosen the reaction 235U, for which the model quantitatively reproduces the measured ternary yields from neutron to carbon isotopes, providing a unified dynamical description for ternary particle production in fission.

Perspectives on Breast Cancer Diagnosis Assisted by Convolutional Neural Networks Applied to High-Sensitivity Talbot-Lau Interferometric Imaging

• Ionut Cristian Ciobanu (XIL)

Early detection of breast cancer remains a crucial objective in modern medicine. High-sensitive X-ray imaging based on Talbot-Lau interferometry offers enhanced soft-tissue contrast compared to conventional mammography, making it a promising tool for non-invasive diagnostics. This work explores the integration of Convolutional Neural Networks (CNNs) with high-sensitivity Talbot-Lau imaging to support and improve automatic tumor detection. We propose a methodological approach consisting of three parts: pre-processing and filtering of raw images to enhance the contrast-to-noise ratio (CNR); classification of scattering images using a ResNet50 model to distinguish between tumors, calcifications, and fibrous tissue; and a precise segmentation of tumor regions using a U-Net architecture. Experimental results demonstrate a significant improvement in both detection accuracy and lesion localization. These findings highlight the considerable potential of integrating advanced phase-contrast imaging with deep learning techniques as a possible decision-support tool for breast cancer screening and diagnosis.

Computational methods for material studies

• Iulia Maria Zai (Target Laboratory)

Computational methods are an important component of studies for understanding materials properties, from their crystallographic structure, to their physical properties. Kaganer method [1], a theoretical model developed to determine the densities of threading dislocation in thin films, and ab initio calculations, performed to obtain information about structural stability and physical properties of some metallic hydrides [2], will be presented. In epitaxial thin films, structural defects are inevitably present. To investigate these defects, Kaganer method was employed to determine the densities of threading dislocations. These parameters were extracted from X-ray diffraction profiles measured in skew geometry, using a computational model proposed by Kaganer et al. [1] that investigates the broadening and the profile of X-ray diffraction peaks. Asymmetric (hkl) reflections were used to extract the edge dislocation density, ρₑ, and the corresponding correlation length, Lₑ, while symmetric (000l) reflections were measured to determine the screw dislocation density, ρₛ, and correlation length, Lₛ. The method was applied to several materials, grown as thin films: GaN, Cr, and SrLaCuO. Using different DFT codes, such as CALYPSO, SIESTA, and ELK, alternative approaches for identifying promising hydride superconductor candidates, that typically are stable only under applied pressures of several tens to hundreds of GPa [3], were explored through ab initio calculations. A series of input parameters, with different roles for each code, were tested in order to calculate electron–phonon interactions and to estimate the critical temperature (Tc) of various hydride compounds (e.g., CrxHy, PdH, and Pd1−xCuxHy). Furthermore, these materials were grown by RF sputtering as thin films with thicknesses on the order of tens of nanometers, after which their crystal structure and physical properties were investigated. References: [1] Kaganer, V.M., Brandt, O., Trampert, A., Ploog, K.H., X-ray diffraction peak profiles from threading dislocations in GaN epitaxial films. Phys. Rev. B Condens. Matter Mater. Phys. 2005, 72, 045423. [2] Shipley, Alice M., et al. "High-throughput discovery of high-temperature conventional superconductors." Physical Review B 104.5 (2021): 054501. [3] Duan, Defang, et al. "Structure and superconductivity of hydrides at high pressures." National Science Review 4.1 (2017): 121-135.

Investigation of prompt neutron energy-angular correlations relative to fission fragment emission from 252Cf (sf)

• Sangeeta Ashok Dhuri (GDED)

The study of particle (n, p, α, and γ) emission in fission phenomena is crucial to understand the involved timescales, the energy dissipation, and the underlying mechanisms of the process. Among these, neutron emission is one of the most experimentally exploited process. Earlier studies of neutron-neutron (n–n) correlations were primarily focused on scission neutrons. More recent measurements have explored the average energy of neutrons detected in coincidence with each other at specific energies, analyzed as a function of the angle between them. These investigations offer indirect insights into the partitioning of excitation energy between the fission fragments during the splitting without measuring the fragments. To gain a deeper understanding of the neutron generation in the fission process, a dedicated measurement was carried out to examine the energy and angular correlations of emitted neutrons with respect to the direction of the fission fragments in the spontaneous fission of the 252Cf nucleus. The reported measurement has been carried out using the ELIGANT-GN array at ELI-NP. In contrast to the previous measurements with this setup where the trigger was provided by prompt fission γ-rays, the array was complemented with a vacuum chamber in order to detect fission fragment. A ²⁵²Cf spontaneous fission source was placed inside the vacuum chamber at the center of the array. The 16 × 16 double sided silicon strip detector (DSSSD) was mounted at a distance of 9 cm from the source for the detection of fission fragments. The neutrons emitted in the fission were measured in coincidence with the fission fragments using thirty-six EJ-301 liquid scintillator detectors mounted at 150 cm for the detection of fast neutrons as well as twenty-five 6Li-glass detectors mounted at 100 cm for the detection of low-energy neutrons. All neutron detectors were arranged in the upper hemisphere and provide high efficiency with excellent timing resolution for time-of-flight energy calculations. The lower hemisphere of the array houses thirty-four large-volume LaBr3:Ce and CeBr3 detectors mounted at a distance of 30 cm to measure the γ-rays emitted in a fission event. Data were collected over a period of six months in order to collect sufficient statistics. The angular distribution of neutrons relative to the detected fission fragments confirms the kinematical focusing of neutrons in the direction of the emitting source. The energy-angular distributions of the neutrons correlated with light fission fragments show good agreement with literature. Moreover, the data are consistent with FREYA model calculations for the fission of the 252Cf nucleus. The analysis is further extended to investigate two-neutron correlations with respect to light fragment. A detailed description of experimental setup, along with an investigation of neutron generation in fission focusing on one- and two- neutron energy-angle correlations relative to the detected fission fragment, will be presented and discussed in the framework of the FREYA model.

Break

Timely detection of radiation biomarkers in non-tumoral cells using Nuclear Magnetic Resonance Spectroscopy

• Ioana Fidel (LGED, Biophysics and Biomedical Application Laboratory)

In the biomedical field, several applications for the High Power Laser Systems are proposed. Delivering a high dose in a very short time and understanding the biomolecular effects of radiation is a challenge with implications for clinical translation. Biological systems are impacted differently by various radiation dose-rates. Finding new ways to detect dose-rate effects as early as possible is mandatory. We propose a protocol for detecting via nuclear magnetic resonance spectroscopy (NMR) differences in the metabolic profiles of cells irradiated using secondary radiation generated at the interaction of the High Power Laser System with a gas target at ELI-NP. We have developed an NMR method for radiation effects in cells. The irradiation setup we proposed uses secondary radiation (electrons) stemming from the interaction chamber of 1 PW laser, operating in pulses delivered onto a gas target. Variations in metabolite concentrations between control and irradiated samples for BV-2 Microglia cells (non-tumoral cells) were measured using high-resolution Nuclear Magnetic Resonance spectroscopy. We show that Magnetic Resonance biomarkers can be used for timely detection of radiation dose-rate effects up to the Gy/ns regime.

LSSM studies in even even Chromium nuclei

• Emanuela Boicu (GDED)

A theoretical model based on the Large Scale Shell Model is employed for the study of low-lying 1+ and 2+ states in medium mass nuclei. The code NuShellX@MSU is used for the study of low-lying M1 modes arising from the interference between orbital and spin magnetic moments in even-even Chromium nuclei.

Irradiation with ultra-intense lasers of nanostructured targets for proton acceleration and X-ray emission

• Stefania - Cristina Ionescu (Target Laboratory)

Nanostructured targets significantly enhance laser-matter interaction by coupling the laser pulse into the target, due to the increased surface area, resulting in higher proton energy cut-off, yield, X-ray or gamma ray emission. However, enhanced coupling is highly dependent on the correlation of the target parameters to the laser pulse characteristics (as laser contrast, wavelength, and pulse duration). Therefore, the diameter and gap between the structures, along with their height and substrate thickness, were controlled via the target fabrication methods. Highly ordered metallic (gold and nickel) nanowires and nanotubes on thin substrates were used as targets for proton acceleration and x-ray emission studies. These targets were irradiated by the 1 PW HPLS from ELI-NP, ultra-short laser pulse, with an intensity of 1021W/cm2, using a single plasma mirror system for pulse cleaning. Radiochromic film stacks and a Thompson parabola were employed as ion diagnostics, and CsI scintillators for the electron and photon signal. An enhancement in the proton yield and in the photon signal, from the nanostructured targets, is discussed and presented, compared to that of flat targets, as well as the dependencies on the target characteristics.

p-11B fusion measurement with ELISSA

• Kabita Kundalia (GDED)

The reaction 11B(p,α)αα is the primary mechanism for 11B burning in the stellar environment, which makes it a reaction of interest in nuclear astrophysics. Additionally, this fusion reaction is also relevant in nuclear fusion reactor development, promising clean energy and relatively simplified reactor engineering. The present work focuses on the cross section measurement of this fusion reaction with proton energies ranging from 300 keV to 2600 keV on the 11B target using the Extreme Light Infrastructure Silicon Strip Array (ELISSA). In this experiment we observe the reaction populating the α0 and α1 channels from the sequential decay of 12C. The precise measurement of the total cross section of these channels can resolve the discrepancies in the existing measurements and can be further used as reliable input for the abundance calculation.

Lunch

Double Layer Foam Targets for Enhanced Laser-Driven Proton Acceleration

• Alexandru Magureanu (LDED)

We report the experimental demonstration of double-layer foam targets (DLFTs), consisting of ultra-low-density carbon foam deposited on thin aluminum foils, for enhanced laser-driven proton acceleration in the TNSA regime. Compared to bare aluminum targets, DLFTs exhibit improved laser absorption and modified preplasma formation, resulting in increased proton cut-off energy and particle flux. The targets were tested over a wide range of laser intensities and contrast conditions, spanning from ~10^13 W·cm⁻² up to ~10^21 W·cm⁻², with and without nanosecond-scale prepulses preceding the main pulse, demonstrating their robustness and effectiveness across multiple experimental configurations.

LLMs in student research activity

• Dmitrii Nistor (LSD)

It is presented the first-hand experience of Large Language Models (LLM) use in the early stages of research activity - the PhD studies. For the past 2 years, LLMs have been released and suffered wide-spread integration within the workflow of almost all industrial and research domains. Here, I present the positive and negative impact of LLMs during my (and my fellow colleagues) studies such as acceleration of the research lifecycle as well as erosion of transparency and scholarly skill sevelopment.

The study of the 3H(α,γ)7Li reaction based on the reciprocity theorem

• Ioana Kuncser (GDED)

The abundances of the light elements can be spectroscopically determined by observing the low-metallicity stars. Usually, those measurements are in agreement with the Big Bang Nucleosynthesis predictions. In particular, the measured abundance of Li7 is 3-4 times lower than expected, discrepancy known as the “cosmological Li problem”. The reaction 3H(α,γ)7Li contributes to the production of Li-7 in Universe and can be studied through its inverse reaction, according to the reciprocity theorem. In consequence, the Li-7 photodisintegration has been measured by our team at the High Intensity γ-ray Source (HIγS) at Duke University (USA) using a silicon detector array (SIDAR) to observe the coincidences between the alpha particles and the tritons. The final number of coincidences has been determined and the preliminary astrophysical S-factor has been extracted. A preliminary R-Matrix fit has been performed over the data from 2023 together with the data from 2017 and from 1994, covering an energy range between 2.5 and 10 MeV.

RF Gun Phase Scan and Beam Emittance Measurement for the GBS LINAC

• Alexandra - Cristina Cană (GSD)

Optimizing RF gun performance is critical for achieving electron beams with the desired parameters in particle accelerators. For the RF gun commissioning of the GBS LINAC at ELI-NP, RF gun phase scan and beam emittance measurement have been studied. The gun phase scan simulation integrates Python-based Gaussian waveform generation with an EPICS control system and a Qt Designer–based user interface. The system models realistic Integrating Current Transformer (ICT) responses over RF phase angles ranging from −90° to +90°, enabling real-time visualization of beam charge as a function of RF phase. Dual ICT detector readings provide independent validation, while automated phase scanning combined with safety interlocks facilitates systematic optimization of the injection phase for maximum beam energy. The emittance module simulates beam profiles by generating two-dimensional intensity distributions along with their projected profiles. Beam matrix elements are extracted from the measured intensity distributions to calculate the beam emittance. Together, these tools enable comprehensive beam quality assessment, covering both charge optimization and spatial distribution characterization. This predictive capability significantly reduces commissioning time and resource consumption by identifying optimal operating parameters prior to hardware testing. The presentation will discuss the simulation algorithms, system architecture, and representative simulation results.

The measurement of the 6Li(p, α)3He reaction using the ELISSA array

• Ana Lupoae (GDED)

The direct measurement of the 6Li(p, α)3He reaction at astrophysical energies using the scaled-down version of the ELISSA array has been performed at the IFIN-HH 3MV Tandetron. The 6Li(p, α)3He reaction plays a key role in stellar nucleosynthesis, being tightly bound to the well-known "Cosmological Lithium Problem" for it takes place in the context of the lithium depletion mechanisms in stars. The total cross-section for the 6Li(p, α)3He reaction has been measured before, in the proton energy range starting from 25 keV to several MeV. The so-called "Second Cosmological Lithium Problem" is concerned with the 6Li isotope primordial abundance discrepancy. It states that the measured abundance exceeds the predictions of the Standard Big Bang Nucleosynthesis theory by several orders of magnitude. The existing 6Li(p, α)3He direct measurement data suffer from large uncertainty, particularly at energies below 500 keV (in the center-of-mass system). Thus, a new direct measurement of the 6Li(p, α)3He reaction at low energies, from 122 keV to 1.2 MeV (4 different beam energies) in the center-of-mass system has been carried out to reduce the uncertainty in the S(E) factor.  In this experiment, a ∼ 2 - 4 pnA beam intensity and self-supported thin polyethylene targets (CH2, about 70 µg/cm2 thick, placed at 90º with respect to the beam axis) were used. The spot size of the 6Li beam on the target was ∼ 1 mm. The scaled-down version of the ELISSA array having 12 X3 position-sensitive strip detectors arranged in a barrel-like configuration was used to detect the transfer alpha. The solid angles of the X3 detectors have been determined from the NPTool simulation. The absolute differential cross-section of the 6Li(p, α)3He reaction has been determined by normalising to the 6Li(p, p)6Li Rutherford scattering cross-section measured in the monitor detector positioned at a 27.6º angle and located 150 mm away from the target. The total cross-sections (σtotal) of 6Li+p was obtained by fitting the angular distributions of the present data with CRC (couple reaction channel) calculations using FRESCO code. The S-factor was deduced from the total cross sections, and compared with the available compilations for 6Li(p, α)3He reaction. The present measurement resulted the S-factor with better consistency and lesser uncertainty, which will contribute to explaining the BBN network calculations.

Improvement of the working methodology using PADC detectors in the ELI-NP Dosimetric Laboratory

• Alberto Florin Grigore (Dosimetry Laboratory)

PADC detectors are made from a thermosetting polymer used as solid-state nuclear track detectors (SSNTDs), being directly sensitive to charged particles and indirectly to neutrons. For this reason, this type of detector is ideal for use at ELI-NP, due to its sensitivity to a wide range of particles and radiation types. A second reason for using these detectors at ELI-NP is the fact that they are passive detectors, thus being independent of the pulsed characteristics of the laser beam. In the dosimetry laboratory at ELI-NP, this type of detector will be used as a passive neutron dosimeter, designed for the assessment of the dose received by occupationally exposed workers and for environmental monitoring. The laboratory is equipped with an automated dosimetric system for reading and analyzing neutron-induced tracks and a dedicated space for chemical etching of the detectors. In order to be used for this purpose, the dosimetric system must pass the tests specified in ISO 21909. One of these tests is the linearity test, which was parțial performed on groups of six detectors at H*(10) doses of 0.3, 1, 3, 10, 30, and 100 mSv. These detectors were read by am international accredited dosimetric laboratory and then at ELI-NP. Following chemical etching and analysis using the automated system, it was observed that some of the detectors exhibited defects originating from the manufacturing process, which made their reading difficult and led to a higher measurement error compared to the other accredited dosimetric laboratory. Consequently, a stricter quality control method for new PADC detectors was adopted în The Dosimetry Laboratory of ELI-NP and the linearity test will be repeated with detectors that pass the quality control, as well as improved system settings to reduce measurement errors.

Design and Implementation of a Scalable Real-Time Temperature and Humidity Monitoring System for the E8 Laboratory

• Andrei-Eugen Neagoe (GDED)

This work presents the design and implementation of a real-time thermal and humidity monitoring system specifically developed for the E8 laboratory within the ELI-NP infrastructure. The continuous operation of complex electronic and experimental equipment generates significant heat, leading to potential hotspots that can compromise experimental precision and equipment safety. Manual monitoring has proven insufficient for rapid intervention. While commercial off-the-shelf solutions exist, they were identified as costly (approximately 6-7 times more expensive), rigid regarding scalability, and dependent on closed-source software. To address these limitations, we developed a custom, open-source solution based on the ESP32 microcontroller and precision AHT21 sensors integrated into custom-designed PCBs. The proposed system features a distributed wireless architecture that eliminates complex cabling, allowing for flexible sensor placement. Collected data is transmitted to a central database and visualized through a real-time heatmap of the laboratory. This interface allows operators to instantly detect thermal anomalies and optimize environmental conditions, ensuring the reliability of the experimental setup through a cost-effective and scalable approach.

Break

Automated Gamma-Ray Spectra Analysis for the ELIADE Detector Array

• Andrei Ionescu-Piatra (GDED)

Gamma-ray detector arrays such as ELIADE generate large volumes of spectral data, making manual analysis impractical during extended measurements. Automated analysis tools are therefore essential for spectra analysis, calibration and detector characterization tasks. This talk presents a flexible software framework for automated gamma-ray spectra analysis, designed to integrate directly into the ELIADE data analysis workflow. The framework combines a C++ ROOT engine for peak finding, fitting, and calibration with a Python layer for data preparation, visualization, and efficiency calculations. The Analysis engine leverages a custom wavelet-based signal processing algorithm to guide peak fitting by revealing the structures of the spectra across multiple scales, improving robustness in complex or noisy conditions.

In Vitro Assessment of Nanoparticle-Mediated X-PDT using a High-Power Laser-Driven Source

• Diana Naum (LDED)

Cancer remains one of the most important global health challenges of the 21st century and one of the leading causes of death worldwide. Radiotherapy is a cornerstone of modern cancer oncology, with more than half of all cancer patients receiving curative or palliative radiotherapy as part of their treatment. However, even with continual technological improvements, radiotherapy can be limited by toxicity to surrounding healthy tissues, resistance mechanisms, and unfavourable tumour locations. These limitations highlight the need for complementary modalities capable of enhancing tumour control while reducing treatment-related side effects. Photodynamic therapy (PDT) is an emerging clinically approved modality that offers high specificity, low invasiveness, and reduced side effects. Under light activation, photosensitizers generate reactive oxygen species (ROS) that induce cytotoxic effects in tumour cells. Nevertheless, conventional PDT suffers from shallow penetration depth due to the strong absorption and scattering of UV-visible light in biological tissues, restricting its application to superficial lesions. To overcome this fundamental limitation, X-ray induced photodynamic therapy (X-PDT) has been proposed, exploiting the deep penetration capability of X-rays. In this study, we present an in vitro assessment of nanoparticle-mediated X-PDT using a high-power laser-driven source. Cerium-doped titanium dioxide (Ce:TiO₂) nanoparticles were synthesized via a sol-gel method and conjugated with a porphyrin-based photosensitizer (TMPyP4), forming a nanoscintillator-photosensitizer nanocomplex. Spectroscopic characterization confirmed successful photosensitizer loading and efficient energy transfer. Biological experiments were performed on breast cancer (MDA-MB-231) and normal epithelial (MCF-12A) cell lines irradiated at the ELI-NP E6 experimental area using a broadband laser-driven Bremsstrahlung X-ray source. Dose rates exceeding 10¹¹ Gy/s were achieved, far above the FLASH radiotherapy threshold. Clonogenic survival, MTT, and comet assays revealed significant DNA damage and cytotoxic effects in cancer cells. These results demonstrate the feasibility and therapeutic potential of laser-driven X-PDT for deep-seated tumour treatment.

Development of an EPICS-Based Control and Monitoring for Particle Accelerator Subsystems

• Andrei Daniel Iancu (GSD)

Developing reliable control infrastructures is essential for ensuring stable operation in modern particle accelerators. This work presents a complete software-based control environment integrating EPICS Soft IOCs, Python-driven data processing, and Qt/PyDM graphical interfaces to simulate and control accelerator subsystems. The system models realistic device behavior through custom IOC databases containing analog and waveform records, including automated alarm handling for fault detection. A multi-layer GUI architecture enables real-time visualization of currents, voltages, vacuum states, and diagnostic signals, while interactive control panels allow operators to adjust parameters and access detailed subsystem displays. Integrated archiving through the LCLS Archiver Appliance provides long-term data retrieval and trend analysis, allowing systematic evaluation of system stability and device performance. Together, these components form a functional prototype capable of emulating core accelerator operations—from live monitoring to historical data analysis—supporting system testing, operator training, and early-stage development without hardware dependencies. The presentation will discuss system design, IOC architecture, GUI implementation, and performance demonstrations of the operational workflow.

Laser–plasma acceleration of quasi-monochromatic carbon ion beams with the “peeler” scheme

• Bogdan Corobean (LDED)

The “peeler” scheme, originally proposed for proton acceleration, involves irradiating the narrow (sub-micron) side of a solid tape target. The large number of extracted electrons travel to the target rear and create a strong space charge field, which efficiently accelerates hydrogen ions found in the contaminant layer. However, the energy spectrum of higher Z (such as carbon) ion bunches is still thermal-like. Using full 3D particle-in-cell simulations with the particle-in-cell code SMILEI, we optimize this process in order to obtain high peak energy, quasi-monochromatic and low divergence carbon ion beams. Thus, with a PW-class laser, we can obtain 1e8 carbon ions with peak energy ~110 MeV/u, with a divergence of 20 degrees in the vertical plane and a remarkable ~1 degree in the horizontal plane. In preparation for an experimental campaign, we also performed a series of robustness tests, which showed that the main characteristics of this scheme are still present under more realistic conditions. We also show some preliminary results from an experiment based on this scheme which was conducted at ELI-NP in September 2025.

Analysis of High-Energy (p,p’) data on 10,11B for the PANDORA Project

• Andreea Ghitiu (Gavrilescu)

The propagation of Ultra-High-energy cosmic rays (UHECR) in extragalactic space has gathered significant attention in the field of high-energy astrophysics. The motivation behind the PANDORA (Photo-Absorption of Nuclei and Decay Observation for Reactions in Astrophysics) project lies in investigating the photo-disintegration and energy loss processes experienced by UHECR particles lighter than iron during their interaction with the strongly Doppler-shifted Cosmic Microwave Background (CMB) photons, seen by UHECRs as high-energy gamma rays. Understanding these complex interactions is essential in comprehending the origins of UHECRs and the mechanisms responsible for their acceleration to such high energy ranges. One of the methods used follows inelastic proton scattering at 0◦ with proton energies of hundreds of MeV, which favors excitation of dipole modes by relativistic Coulomb excitation. Another method is to use real gamma rays from a dedicated photon facility. For achieving this goal, a joined collaboration between ELI-NP, RCNP, and iThemba LABS has been created. In both the iThemba and RCNP labs, an array of double-sided Si strip detectors and a magnetic spectrometer are used for particle decay and excitation strength. The gamma decay branches will be measured with large-volume LaBr3 : Ce detectors. Here we will present the PANDORA project and report preliminary analysis from the first experiment at RCNP on 10,11B. These measurements can further be used to constrain the propagation and the origin of UHECRs.

On the cosmological implications of characteristic energy scales in nuclear level density

• Cosmina Nedelcu (GDED)

Understanding how elements are formed in the universe requires a detailed knowledge of the nuclear reactions that govern nucleosynthesis. Particle capture and photo-absorption reactions are particularly important, as they compete to build up or dismantle nuclei in stellar and explosive environments. The probabilities of these reactions are governed by cross-sections, which in turn depend sensitively on the nuclear level density (NLD) and the structure of available excited states. Through their impact on reaction rates under astrophysical conditions, NLDs and cross-sections determine the balance between capture and photodisintegration, thereby shaping nucleosynthesis pathways and the resulting elemental abundances. In nuclear astrophysics, the critical influence of the NLD on reaction rate calculations has been well established. However, the specific NLD energy range that has the greatest impact on the cross-section and reaction rate, respectively, still remains unclear. Within this work, the NLD energy regions that most significantly affect capture and photo-absorption reactions relevant to nucleosynthesis are analyzed. While previous studies have extensively investigated the sensitivity of reaction cross-sections to variations in the photon strength function, a systematic analysis of cross-section and reaction-rate sensitivities to the NLD over different energy ranges is performed. This study employs microscopic NLDs derived from the Hartree–Fock–Bogoliubov plus combinatorial approach within the Hauser-Feshbach framework to quantify the impact of NLD variations on calculated observables. In addition, the microscopic NLD is compared with experimentally extracted NLDs obtained using the Oslo method for the 120Sn(n,γ)121Sn reaction. The presence of significant uncertainties in the experimental data within the energy range that contributes most strongly to the calculated observables highlights the need for further experimental and theoretical investigations. Improved constraints in this energy range are expected to provide valuable input for refining nuclear models and guiding future measurements, especially those targeting level schemes at moderate excitation energies.

Markers' Session