Proton therapy offers superior dose localization, yet the biological effects of low-energy protons relevant to superficial tissues remain underexplored. We report the design and validation of a proton irradiation setup developed at the Tandem Accelerator of NCSR “Demokritos” for controlled radiobiological experiments. Monte Carlo simulations using Geant4 and Monte Carlo Damage Simulation (MCDS—Monte Carlo Damage Simulation) were used to determine proton energy spectra, linear energy transfer (LET), and predicted DNA damage yields. A single layer (15–20 μm in thickness) of human keratinocytes (HaCaT) was irradiated at doses from 0.65 to 3.65 Gy, and γ-H2AX foci were quantified as markers of tracks including one or more DNA double-strand breaks. The system achieved a uniform dose rate of 0.37 Gy/min, as calculated with Geant4, with a mean proton energy of 4.1 MeV (LET ≈ 8 keV/μm). A strong correlation (R2 = 0.93) was observed between proton dose and γH2AX foci per nucleus (~10 foci/Gy), reflecting damage-inducing proton tracks rather than individual DNA double-strand breaks. At higher doses, an increased fraction of cells exhibited pan-nuclear γH2AX staining, characterized by a diffuse γH2AX signal throughout the nucleus and commonly associated with extensive or clustered DNA damage and global chromatin phosphorylation. These responses are consistent with the well-established dense ionization patterns produced by low-energy protons, as indicated by the LET spectrum and supported by MCDS-predicted clustered damage yields. While the γH2AX assay does not directly resolve simple versus complex DNA lesions, the agreement between Monte Carlo modeling and the observed cellular stress responses indicates that the irradiation platform reliably reproduces the expected biological signatures of low-energy proton exposure. Consequently, the developed system provides a robust experimental tool for systematic investigations of cellular radiosensitivity and radiotoxicity, with potential applications in skin dosimetry and radioprotection.

The cross section of the 100Mo(n, 2n)99Mo reaction has been measured with the activation technique and 27Al(n, α)24Na as reference reaction, at 16.0 MeV and 14.6 MeV. Both energies were achieved at N.C.S.R. “Demokritos” during the same irradiation, placing the target assembly both at 0° and 80° with respect to the main neutron beam, which was produced via the 3H(d, n)4He reaction. In this work, the neutron production at 14.6 MeV was thoroughly investigated experimentally and via Monte Carlo simulations with the MCNP6 code, as it was used for the first time at N.C.S.R. “Demokritos” for cross section measurements. Two simulations were carried out: the first one to study energy variations with laboratory angle, and the second to replicate this specific experiment using a 2.15 MeV deuteron beam and targets positioned at 0° and 80°, corresponding to neutron energies of 16.0 MeV and 14.6 MeV respectively. Both 100Mo(n, 2n)99Mo and 27Al(n, α)24Na reactions were employed to validate the simulation results. Good agreement between simulation and experiment demonstrates that the approach reliably reproduces both the angular and energy characteristics of the neutron beam, providing a foundation for further studies at additional neutronenergies and angles.

Following the upgrade of the tandem accelerator at NCSR “Demokritos”, the determination of the new neutron flux was necessary for further neutron induced experiments. For the investigation of the energy dependence of the neutron flux at 18 MeV, the multiple foil activation technique has been used, in combination with two codes. With Monte Carlo simulation based code MCNP5 and unfolding code SAND-II .

Background: Calculations of p-nuclei abundances depend heavily on the Hauser-Feshbach (HF) theory to compute cross sections and, consequently, the reaction rates entering a huge reaction network encompassing nearly 2000 isotopes, the vast majority of which are unstable. Therefore, the successful reproduction of p-nuclei abundances relies on the reliability of the nuclear parameters entering the HF calculations, i.e., the optical model potential (OMP), the nuclear level density (NLD), and the gamma-ray strength function ( gamma SF). Purpose: New cross sections, astrophysical S factors, and reaction rates for ( p , gamma ) reactions on 116 Sn and 118 Sn were measured at energies relevant to the p process with the aim of validating OMP, NLD, and gamma SF models and investigating their "global" character, with particular emphasis on the Lane-consistent semimicroscopic OMP developed by Bauge et al. [Bauge, Delaroche, and Girod, Phys. Rev. C 63 , 024607 (2001)]. Method: Cross sections were determined from gamma-angular distribution measurements, angle-integrated gamma spectra taken with the 4 7r gamma-summing technique, and off-beam gamma activities measured with the activation method. HF calculations were performed with the TALYS code (version 1.96). Results: Total and partial cross sections were determined for the 116 Sn( p , gamma ) 117 Sb and 118 Sn( p , gamma ) 119 Sb reactions at energies ranging from 2.2 to 5.2 MeV. These energies cover almost entirely the Gamow window relevant to p-process nucleosynthesis. The experimentally determined cross sections and the resulting S factors were corrected for electron screening effects and subsequently compared with HF calculations, which were performed using various combinations of phenomenological or semi-microscopic models describing the proton-nucleus OMP ( p-OMP), alpha-particle-nucleus OMP ( alpha-OMP), NLD, and gamma SF. Conclusions: Our screening-corrected data were found to be in very good agreement with the corresponding calculations performed using a combination of the p-OMP of Bauge et al. with semimicroscopic models for the alpha-OMP, NLD, and gamma SF. This agreement resulted from adjusting the energy dependent isoscalar normalization factors lambda V and lambda W for the real and imaginary components of the OMP. The model combination used by default in TALYS 1.96, which includes only phenomenological models for the nuclear parameters entering the HF calculations, was less successful in reproducing our screening-corrected data. The NLDs used in our TALYS calculations were compared with the experimental cumulative numbers of low-lying levels observed in 117 Sb and 119 Sb. Average radiative widths from the systematics were also used to validate the combination of NLD and gamma SF models found to best reproduce our data. Finally, the stellar reaction rates obtained in the present work were compared with those provided in the REACLIB and BRUSLIB databases. In the temperature range relevant to the p process, it was found that the REACLIB stellar rates are smaller by a factor of approximate to 2, whereas the BRUSLIB rates exhibit deviations of no more than 20%.

In 2021 JET exploited its unique capabilities to operate with T and D-T fuel with an ITER-like Be/W wall (JET-ILW). This second major JET D-T campaign (DTE2), after DTE1 in 1997, represented the culmination of a series of JET enhancements-new fusion diagnostics, new T injection capabilities, refurbishment of the T plant, increased auxiliary heating, in-vessel calibration of 14 MeV neutron yield monitors-as well as significant advances in plasma theory and modelling in the fusion community. DTE2 was complemented by a sequence of isotope physics campaigns encompassing operation in pure tritium at high T-NBI power. Carefully conducted for safe operation with tritium, the new T and D-T experiments used 1 kg of T (vs 100 g in DTE1), yielding the most fusion reactor relevant D-T plasmas to date and expanding our understanding of isotopes and D-T mixture physics. Furthermore, since the JET T and DTE2 campaigns occurred almost 25 years after the last major D-T tokamak experiment, it was also a strategic goal of the European fusion programme to refresh operational experience of a nuclear tokamak to prepare staff for ITER operation. The key physics results of the JET T and DTE2 experiments, carried out within the EUROfusion JET1 work package, are reported in this paper. Progress in the technological exploitation of JET D-T operations, development and validation of nuclear codes, neutronic tools and techniques for ITER operations carried out by EUROfusion (started within the Horizon 2020 Framework Programme and continuing under the Horizon Europe FP) are reported in (Litaudon et al Nucl. Fusion accepted), while JET experience on T and D-T operations is presented in (King et al Nucl. Fusion submitted).

In the present work, the differential cross-sections of the 18O(p,α0)15N reaction were determined using the absolute measurement technique, in the proton energy range Ep=1–2 MeV for NRA purposes. The experiment was carried out in energy steps of 10 or 20 keV. Two detection angles, 170° and 160°, were measured, employing 500 μm thick Surface-Barrier-Back-Scattering detectors in a high-precision goniometric chamber. The target, a thin layer of Ta2O5 highly enriched in 18O, was deposited ona thick tantalum foil via anodization. Its thickness was provided by the manufacturer and independently verified experimentally using the 18O(d,α0) reaction. SIMNRA simulations were performed to determine the Q•Ω value, incorporating a pile-up calculation routine. The obtained results were compared with previously published data, allowing for a comprehensive analysis of both similarities and discrepancies. The reaction’s differential cross-section was determined using the absolute measurement technique. The final results revealed larger cross-section values compared to the existing literature ones. Some of the observed discrepancies were attributed to inaccuracies in the database entries. These coherent differential cross-section datasets are expected to facilitate the extension of the existing SigmaCalc evaluation of the 18O(p,α0) reaction to higher energies in the near future.

Several cross-section measurements of neutron-induced reactions on Ge found in literature, are performed utilizing natGe targets. The production of the same residual nucleus as the measured one might occur as a result of the unavoidable presence of neighboring isotopes in the same target, acting as a contamination. Corrections must be made based on theoretical calculations and models in order to resolve this problem. The accuracy and limits of a methodology for these “theoretical corrections” are investigated in this work using isotopically enriched targets, which can produce very accurate results without the need for such corrections. Experimental cross-section measurements have been made for the 76Ge(n,2n)75Ge, 72Ge(n,α)69mZn and 72Ge(n,p)72Ga reactions, via the activation technique, with the 27Al(n,α)24Na reaction used as reference, employing both a natGe and isotopically enriched Ge targets. The 3H(d,n)4He (D–T) reaction was used for producing the quasi-monoenergetic neutron beam in the 5.5 MV Tandem Accelerator Laboratory of the National Centre for Scientific Research “Demokritos” in Athens, Greece, at an incident deuteron beam energy of 2.9 MeV. Using HPGe detectors, γ-ray spectroscopy was applied to determine the induced γ-ray activity of the residual nuclei.

Neutron induced reaction cross-section measurements display special interest both for fundamental research in the Nuclear Physics field and many practical applications. The Institute of Nuclear and Particle Physics (INP) of the National Centre for Scientific Research Demokritos (N.C.S.R. “D”) hosts the 5.5 MV T11/25 Van de Graaff accelerator, which is the only accelerator used in Greece for research purposes. This accelerator recently underwent a major upgrade, including the installation of a new pelletron charging system, two new ion sources, a new gas stripper and beam optics. This neutron facility can produce quasi-monoenrgetic neutron beams in the energy range ∼16-19 MeV via the 3 H(d,n)4 He (D-T) reaction, employing a tritiated Titanium target (TiT). The neutron induced cross sections of a total of nine reaction channels have been experimentally measured in the present work, via the activation technique, using enriched Ge targets. These targets produce more accurate cross-section results, in comparison with the - most commonly used in bibliography - nat Ge samples, since they do not suffer from contaminating reactions that produce the same residual nucleus. Monte Carlo simulations were also performed via the combined use of MCNP5 and NeuSDesc codes for the simulation of the neutron beam.

The cross sections of the 70 Ge( n , 2n) 69 Ge, 72 Ge( n , alpha ) 69m Zn, 72 Ge( n , p ) 72 Ga, 73 Ge( n , n alpha ) 69m Zn, 73 Ge( n , np / d ) 72 Ga , 73 Ge( n , p ) 73 Ga , 74 Ge( n , alpha ) 71m Zn , 74 Ge( n , np / d ) 73 Ga, and 76 Ge( n , 2n) 75 Ge reactions have been experimentally determined via the activation technique, relative to the 27 Al( n , alpha ) 24 Na reference reaction in the energy range between 14.0 and 18.9 MeV. The quasi-monoenergetic neutron beams were produced via the 3 H( d , n ) 4 He reaction at the neutron beam facilities of NCSR "Demokritos" (Greece) and the accelerator for metrology and neutron applications in external dosimetry (AMANDE) of the Institute of Radiation Protection and Nuclear Safety (IRSN, France). After each irradiation, the samples' induced radioactivity was measured via gamma-ray spectroscopy using HPGe detectors. Isotopically enriched Ge targets were utilized for all crosssection measurements, yielding more accurate cross-section results in comparison with the more widely used natural ones. Finally, theoretical calculations were performed via the EMPIRE 3.2.3 code, employing a coherent set of input parameters for the successful reproduction of all the aforementioned reaction channels.

In the current work the first coherent set of differential cross section values for the natMg(p,p0)natMg elastic scattering covering the Ep,lab = 2700-4250 keV energy range is presented for 6 backscattering detection angles (120 degrees, 130 degrees, 140 degrees, 150 degrees, 160 degrees and 170 degrees). R-Matrix calculations were implemented using the AZURE 2.0 code [1] in an attempt to reproduce the obtained experimental data, whilst taking into account the 24Mg(p,p1)24Mg reaction channel. Both results are suitable for EBS and other IBA applications and, furthermore, they form a basis for a future expansion of the current SigmaCalc [2] evaluation, once more experimental data become available. The measurements were performed in the 5.5 MV TN11 HV Tandem Accelerator and the high precision goniometer of N.C.S.R. 'Demokritos', Athens, Greece. The experimental and data analysis procedures are presented in detail, along with the process behind the implementation of the R-Matrix calculations.

A simulation code was developed using the GEANT4 [1] toolkit in order to determine the behavior of the neutron production beams generated by proton induced reactions while applying the cross section biasing technique [2]. As the application of the biasing technique can cause a change in the physical processes occurring during the simulation, the specific implemented technique was tested via control simulations to determine any deviations of the results from the theoretically expected ones. Different materials, geometries and biasing factors were used in order to qualify and quantify the discrepancies between the unbiased and the biased simulations. One of the main reactions used for the production of the neutron beam at the Tandem accelerator laboratory of N.C.S.R. “Demokritos” [3] is the 3H(p,n)3He one. In the geometry of the main tritiated target, elements such as molybdenum, copper and titanium are included. During the interaction of the proton beam with them, it is possible to produce neutrons that will “contaminate” the main neutron beam. These neutrons are called parasitic and their quantification is necessary in order to avoid obtaining erroneous results in cross section measurements on the various targets under study.[4] By constructing the proper geometry and using the GEANT4 code mentioned above, the determination of the parasitic neutrons is achieved with optimal statistical results in short computational times, while the discrepancies between the unbiased and the biased results remain minimal.

Differential cross sections of the reaction 7Li(p,pGREEK TONOS gamma 1-0)7Li were experimentally determined in the proton energy range between 1000 and 4000 keV. The experiment was conducted at the Tandem Accelerator Laboratory of N.C. S.R. "Demokritos". The detection of the emitted gamma rays, having an energy E gamma = 477.6 keV, was accomplished using four HPGe detectors of relative efficiency varying between 18 and 80%, at the detection angles of 0 degrees, 55 degrees, 90 degrees and 165 degrees. The statistical errors of the measurements did not exceed 4%, while the overall systematic uncertainty budget was also kept as low as possible (-8%). For the validation of the obtained cross sections a benchmarking experiment was performed using a thick target of known stoichiometry. The comparison with existing experimental datasets in literature is also presented and discussed.

In this study we present the experimental cross sections of the natO(p,p0) elastic scattering, determined via the relative measurement technique, in the proton energy range Elab=4-6 MeV, at six backscattering detector angles between 120o and 170o, with a 10o step. The measurements were performed using the Van de Graaff Tandem 5.5 MV Accelerator of N.C.S.R. “Demokritos” in Athens, Greece and a high precision goniometer.

The aim of the present work was to study the cross-section of the (n,2n) and (n,3n) reactions on 203Tl, by irradiating a natural TlCl pellet target with monoenergetic neutron beams at 16.4, and 18.9 MeV. The cross section measurements were carried out using the activation method, with respect to the 197Au(n,2n)196Au and 27Al(n,α)24Na reference reactions. The monoenergetic neutron beams were generated in the 5.5 MV Tandem accelerator of NCSR “Demokritos”, using the 3H(d,n)4He reaction. Monte Carlo simulations have been performed to take into account the gamma-ray self-absorption results as well as the estimation of the neutron flux through the reference foils. Theoretical calculations with the code EMPIRE have also been performed, using the same parameterization implemented in the theoretical study of Ir and Au nuclei in an attempt to find a suitable model for the description of all the experimental results in this mass region.

In this work, the cross sections of the neutron induced reactions 70Ge(n,2n)69Ge, 76Ge(n,2n)75Ge, 73Ge(n,p)73Ga, 72Ge(n,p)72Ga, 73Ge(n,d/np)72Ga, 74Ge(n,d/np)73Ga, 74Ge(n,α)71mZn, 72Ge(n,α)69mZn, 73Ge(n,nα)69mZn have been measured in the energy range between 16.4 and 18.9 MeV via the activation technique with respect to the 27Al(n,α)24Na reference reaction. Most of the existing experimental datasets found in literature for these reactions, were obtained with the use of a natGe target. In this case however, the residual nucleus produced from some reaction channels, could also be produced from neutron induced reactions in neighboring isotopes that exist in the natGe in their natural abundance, acting as a contamination to the measured yield of the reaction of interest. This parasitic contribution should then be subtracted, based on theoretical calculations that bear their own uncertainties. Isotopically enriched targets on the other hand, do not suffer from such contaminations, leading to more accurate experimental cross section results. In this work, five highly enriched targets have been used that helped in the determination of accurate cross section data, especially in the case of the73Ge(n,d/np)72Ga, 74Ge(n,d/np)73Ga and 73Ge(n,nα)69mZn challenging reactions, that will be presented in detail in this manuscript. The experiments were carried out at the 5.5 MV Tandem Van de Graaff accelerator of N.C.S.R. “Demokritos”, implementing the 3H(d,n)4He reaction for the production of the quasi-monoenergetic neutron beams.

A major task in experimental nuclear astrophysics is the measurement of cross sections of capture reactions. In the last years, the astrophysics group of NCSR “ Demokritos ” developed and used a method for conducting this kind of research using a 4 π NaI γ -detector [1]. Of great importance in this method is the determination of the efficiency of the detector, which depends on the average multiplicity of the γ -cascade de-exciting the entry state of the produced nucleus. Two new experimental setups have been studied and are in course of installation at the Tandem Laboratory of the Institute of Nuclear and Particle Physics of NCSR “ Demokritos ” , that will provide the possibility for conducting this kind of experiments inhouse. The first one is a new 14x14 inches NaI detector and the second is the BGO Ball of the GASP setup. These detector setups as well as their potential experimental use will be described in detail.

In this study we present the experimental differential cross sections of natO(p,p0) elastic scattering, determined via the relative measurement technique, in the proton beam energy range Elab=4-6 MeV with a varying step (from 5-15 keV), at six backscattering detector angles between 120o and 170o (every 10o). A thin, self-supporting target manufactured in the lab was used in this experiment and the determination of its stoichiometry was carried out according to the currently existing evaluation, which has also been benchmarked recently. The measurements were performed using the Van de Graaff Tandem 5.5 MV Accelerator of N.C.S.R. “Demokritos” in Athens, Greece. The differential cross-section datasets obtained in the present work and already existing ones in literature for this extended proton beam energy range are shown and the observed peculiarities and discrepancies are discussed and analyzed.

Differential cross sections of the 6Li(d,n'gamma)7Be, 6Li(d,p'gamma)7Li, 7Li(d,d'gamma)7Li and 19F(d,p'gamma)20F reactions were determined at three detection angles (0 degrees, 55 degrees and 90 degrees), for deuteron energies ranging from 1000 keV up to 2200 keV, with a 20 keV step. For the detection of the gamma-ray peaks of interest at E gamma = 429 keV, E gamma = 478 keV and E gamma = 656 keV, two different LiF targets were used. Three HPGe detectors having a 80% relative efficiency were placed around the targets for the detection of the gamma-ray peaks under study. The present results are compared with existing ones from the literature and the erroneous omission of the 7Li(d,d'gamma)7Li reaction contribution in the yield of the 478 gamma ray in natLi targets is discussed and analyzed. Comparisons with previously reported absolute thick target yields are also performed. Despite the fact that the differential cross sections determined in the present work are in very good agreement with previously reported differential cross-section datasets in literature (properly corrected), remarkable discrepancies in the case of existing absolute thick target yields are observed.

Experimental cross section measurements for the 176 Hf(n,2n) 175 Hf and 174 Hf(n,2n) 173 Hf reactions were carried out, using the activation technique. The neutron beam energy in the range of 15.3-20.3 MeV was produced via the 3 H(d,n) 4 He reaction at the 5.5 MeV Tandem Van de Graaf accelerator laboratory of NCSR “Demokritos”. A thin metallic foil of natural Hf was used, while for the determination of the neutron flux at the target position, reference foils of Al were placed at the front and back of the Hf target. The irradiations were continuous for ~24-48 hours, leading to a total neutron fluence of 10 10 -10 11 n/cm 2 and a BF 3 detector was used for monitoring the neutron flux during the irradiations. After the end of each irradiation, the activity of the Hf target and the Al reference foils were measured off-line by two HPGe detectors. The 176 Hf(n,2n) 175 Hf reaction has been corrected for the contribution of the 177 Hf(n,3n) 175 Hf and 174 Hf(n,γ) 175 Hf reactions. Statistical model calculations based on the Hauser-Feshbach theory have also been performed using the EMPIRE 3.2.3 code. The predictions have been compared with the data of the present work as well as with data from literature.

Nine neutron induced reactions on Ge isotopes ( 70 Ge(n,2n) 69 Ge, 76 Ge(n,2n) 75 Ge, 73 Ge(n,p) 73 Ga, 72 Ge(n,p) 72 Ga, 73 Ge(n,d/np) 72 Ga, 74 Ge(n,d/np) 73 Ga, 74 Ge(n,α) 71m Zn, 72 Ge(n,α) 69m Zn, 73 Ge(n,nα) 69m Zn) have been measured in this work at energies 16.4-18.9 MeV. For these reactions, most of the experimental datasets in literature were obtained with a nat Ge target. However, the residual nucleus produced by some reaction channels can also be produced from neighboring isotopes, acting as a contamination for the measured reactions. This contribution must be subtracted, based on theoretical calculations, bearing their own uncertainties. The use of enriched targets however, does not suffer from such contaminations, leading to accurate experimental results. In this scope, five highly isotopically enriched Ge samples have been used in this work. The quasi-monoenergetic neutron beams were produced via the 3 H(d,n) 4 He reaction at the 5.5 MV Tandem Van de Graaff accelerator of N.C.S.R. ‘Demokritos’. The cross section of these nine reactions were measured using the activation method, with respect to the 27 Al(n,α) 24 Na reference reaction.