Earthquakes, as one of the most prominent natural disasters, pose a severe threat to societies in regions near active fault lines. Being able to forecast when, where and how strong an earthquake will be is beyond current scientific capabilities. At present, forecasting methods yield earthquake occurrence probabilities within a specific time frame spanning several years. Measurements of changes of radon concentrations in groundwater have shown pronounced changes preceding imminent earthquakes. The potential in using radon as a precursor for earthquakes has been explored by multiple groups over many years. Radon measurements in soil have shown large variations in activity, partly due to atmospheric influences. The ArtEmis project seeks to offer new insight into the correlation between imminent earthquakes and changes in radon emission from the upper crust by employing novel concepts for measurements and analysis. The paper presents system aspects of the ArtEmis project, a description of the ArtEmis sensor prototype and first results.

Radon is increasingly recognized as a geogas tracer for geodynamic processes and a potential earthquake precursor. The European ArtEmis project aims to investigate earthquake hydrogeology, utilizing a European network of advanced, low-cost sensors to explore radon concentration pre-, co- and post-seismic changes and anomalies, in groundwater of key seismogenic sites. In Italy, this project focuses on monitoring radon concentration in groundwater of Abruzzo region chosen for its high seismicity. The selection process of the hydrosensitive to seismicity sites in Abruzzo, where sensors will be installed, is outlined in this study. As radon concentrations in groundwater are believed to be less susceptible to the shallow phenomena than radon measurements in soil gas, radon monitoring will be carried out only within carefully selected high-discharge springs. Site selection prioritized hydrosensitive to seismicity locations, considering source rock properties, hydrogeological and seismotectonic settings and seismic activity, viewed as main factors influencing radon release. Potential sites, including carbonate aquifers, intermontane plains, and spa areas, were identified due to their interaction with main seismogenic faults, high-discharge springs, and potential geogas upwelling. These springs are representative of large rock volumes crossed by seismogenic faults, reflecting deep processes, such as the radon upwelling, minimally influenced by shallow or seasonal water cycle variations.

In the last two decades, several unique phenomena in triaxially deformed nuclei, such as chiral doublet bands and wobbling motion have been revealed. Up to now, there are still many open questions which require further experimental and theoretical studies. To explore the collective motion in 131Ba, an experiment was performed using the XTU Tandem accelerator in the Legnaro laboratory, Italy. High-spin states of 131Ba have been populated via the heavy-ion fusion-evaporation 122Sn(13C, 4n) reaction. g-rays, charged particles and neutrons emitted from the residues were detected by the GALILEO array, EUCLIDES silicon ball, and the Neutron Wall, respectively. A total of 1.2 ×109 triple- or higher-fold events were collected by the GALILEO data acquisition system. The g-g-g coincidence events were sorted into a three-dimensional histogram (cube) and the analysis was carried out with the RADWARE and GASPWARE software packages. Through analysis of the coincidences between g-rays, the most comprehensive level schemes of 131Ba to date was deduced from the present work. The extended level-scheme consists of 15 rotational bands, and newly observed transitions are marked in red. Three nearly degenerate pairs of doublet bands (Band 3–8) are identified in 131Ba. Two pairs of chiral doublets (Band 3–6) with configuration πh11/2(g7/2,d5/2)×νh11/2 are interpreted as a set of pseudospin-chiral quartet bands. The quartet bands are fed by another pair of chiral doublet bands (Band 7–8) built on a πh211/2×νh11/2 configuration via a series of enhanced E1 transitions. We extracted the energy displacement δE and the B(E1)/B(E2) branching ratios between the positive-parity band 3 and the negative-parity band 7 in 131Ba and in comparison with those in 124Ba, 224Th, 133Ce and 135Nd. The energy displacement δE and the B(E1)/B(E2) branching ratios in 131Ba are comparable with those in 124Ba but deviate appreciably from those in 224Th which has been reported to have stable octupole deformation. The results indicate the existence of octupole correlations in 131Ba without stable octupole deformation. A new rotational band (Band 10) discovered in the low-spin region exhibits a level structure similar to a wobbling band. Assuming it as a wobbling band, the wobbling frequency was extracted and compared with other reported wobbling bands in the neighboring nuclei. The wobbling frequency of this band decreases with increasing angular momentum, and even exhibits negative value at the highest spin. Considering that the wobbling phonon should contribute a positive amount to the excitation energy, this band is unlikely to be explained by this mechanism. The band may originate from other collective excitation mechanisms such as g vibration. The newly identified rotational band (Band 9) composed of M1 transitions is tentatively assigned as a magnetic rotational band through a systematic analysis of the level structure. Finally, the configurations of other 4 bands, Band 12-15, are also suggested based on previous researches and the extracted quasiparticle alignments.

The manuscript provides a comprehensive review of the results that have been obtained from radon concentrations in the ground, particularly their correlation with earthquakes, over the past fifty years in Greece. Data collection methods have evolved from solid-state nuclear track detectors to more advanced continuous monitoring devices. The influence of meteorological parameters was eliminated through time series analysis, revealing correlations between radon signals and earthquakes M3.5–6.5. Anomalies persisted for days to weeks, depending on the faulting type. The review concludes with a discussion and evaluation of the results, highlighting the potential for future research on this intriguing correlation between radon and earthquakes.

Excited states in the neutron-deficient nucleus Tc-87 have been studied via the fusion-evaporation reaction 54Fe(36Ar, 2n1p) Tc-87 at 115 MeV beam energy. The AGATA gamma-ray spectrometer coupled to the DIAMANT, NEDA, and Neutron Wall detector arrays for light-particle detection was used to measure the prompt coincidence of gamma rays and light particles. Six transitions from the deexcitation of excited states belonging to a new band in Tc-87 were identified by comparing gamma-ray intensities in the spectra gated under different reaction channel selection conditions. The constructed level structure was compared with the shell model and total Routhian surface calculations. The results indicate that the new band structure in 87Tc is built on a spherical configuration, which is different from that assigned to the previously identified oblate yrast rotational band.

The quantum tunneling and emission of a single constituent nucleon provide a beautifully simple and unique window into the complex properties of atomic nuclei at the extreme edge of nuclear existence. In particular, for odd-odd proton emitting nuclides, the associated decay energy and partial half-life can be used to probe the correlations between the valence neutrons and protons which have been theoretically predicted to favour a new type of nuclear superfluidity, isoscalar neutron-proton pairing, for which the experimental "smoking gun" remains elusive. In the present work, proton emission from the lanthanum isotope La-116(57)59, 23 neutrons away from the only stable isotope La-139(57)82, is reported. La-116 nuclei were synthesised in the fusion-evaporation reaction Ni-58(Zn-64, p5n)La-116 and identified via their proton radioactivity using the mass spectrometer MARA (Mass Analysing Recoil Apparatus) and the silicon detectors placed at its focal plane. Comparisons of the measured proton energy (E-p = 718 +/- 9 keV) and half-life (T-1/2 = 50 +/- 22 ms) with values calculated using the Universal Decay Law approach indicate that the proton is emitted with an orbital angular momentum l = 2 and that its emission probability is enhanced relative to its closest, less exotic, odd-even lanthanum isotope (La-117(57)60) while the proton-emission Q-value is lower. We propose this to be a possible signature for the presence of strong neutron-proton pair correlations in this exotic, neutron deficient system. The observations of. decays from isomeric states in La-116 and La-117 are also reported.

The low-lying excited states in the neutron-deficient N = Z + 1 nucleus (87)(43)Tcc(44) have been studied via the fusion-evaporation reaction Fe-54(Ar-36, 2n1p)Tc-87 at the Grand Accelerateur National d'Ions Lourds (GANIL), France. The AGATA spectrometer was used in conjunction with the auxiliary NEDA, Neutron Wall, and DIAMANT detector arrays to measure coincident prompt gamma rays, neutrons, and charged particles emitted in the reaction. A level scheme of Tc-87 from the (9/2(g.s.)(+)) state to the (33/2(1)(+)) state was established based on six mutually coincident gamma-ray transitions. The constructed level structure exhibits a rotational behavior with a sharp backbending at (h) over bar omega approximate to 0.50 MeV. A decrease in alignment frequency and increase in alignment sharpness in the odd-mass isotonic chains around N = 44 is proposed as an effect of the enhanced isoscalar neutron-proton interactions in odd-mass nuclei when approaching the N = Z line.

The antiproton experiment PANDA at FAIR is designed to bring hadron physics to a new level in terms of scope, precision and accuracy. In this work, its unique capability for studies of hyperons is outlined. We discuss ground-state hyperons as diagnostic tools to study non-perturbative aspects of the strong interaction, and fundamental symmetries. New simulation studies have been carried out for two benchmark hyperon-antihyperon production channels: p¯ p→ Λ¯ Λ and p¯ p→ Ξ¯ +Ξ-. The results, presented in detail in this paper, show that hyperon-antihyperon pairs from these reactions can be exclusively reconstructed with high efficiency and very low background contamination. In addition, the polarisation and spin correlations have been studied, exploiting the weak, self-analysing decay of hyperons and antihyperons. Two independent approaches to the finite efficiency have been applied and evaluated: one standard multidimensional efficiency correction approach, and one efficiency independent approach. The applicability of the latter was thoroughly evaluated for all channels, beam momenta and observables. The standard method yields good results in all cases, and shows that spin observables can be studied with high precision and accuracy already in the first phase of data taking with PANDA.

Three nearly degenerate pairs of doublet bands are identified in Ba-131. Two of them, with positive-parity, are interpreted as pseudospin-chiral quartet bands. This is the first time that a complete set of chiral doublet bands built on the pseudospin partners pi(d(5/2), g(7/2)) is observed. The chiral bands with opposite parity built on 3-quasiparticle configurations are directly connected by many E1 transitions, without involving an intermediary non-chiral configuration. The observed band structures in Ba-131 have been investigated by using the reflection-asymmetric particle rotor model. The energies and the electromagnetic transition ratios of the three pairs of doublet bands observed in Ba-131 are reproduced and they are interpreted as chiral doublet bands with three-quasiparticle configurations. It is the first time that multiple chiral bands are observed in the presence of enhanced octupole correlations and pseudospin symmetry. 

The low-lying energy spectrum of the extremely neutron-deficient self-conjugate (N = Z) nuclide 88Ru has been measured using the combination of the Advanced Gamma Tracking Array (AGATA)spectrometer, the NEDA, and Neutron Wall neutron detector arrays, and the DIAMANT charged particle detector array. Excited states in 88 Ru were populated via the 54 Feð 36 Ar; 2nγÞ 88 Ru fusion-evaporationreaction at the Grand Accélérateur National d’Ions Lourds (GANIL) accelerator complex. The observed γ-ray cascade is assigned to 88 Ru using clean prompt γ-γ-2-neutron coincidences in anticoincidence with the detection of charged particles, confirming and extending the previously assigned sequence of low-lying excited states. It is consistent with a moderately deformed rotating system exhibiting a band crossing at a rotational frequency that is significantly higher than standard theoretical predictions with isovector pairing, as well as observations in neighboring N > Z nuclides. The direct observation of such a “delayed” rotational alignment in a deformed N 1⁄4 Z nucleus is in agreement with theoretical predictions related to the presence of strong isoscalar neutron-proton pair correlations.