Segmented high-purity germanium detectors are at the heart of cutting-edge gamma spectroscopy. However, their technical and manufacturing specifications are not known, since they are provided by industry. To bridge this gap, Italy’s INFN launched the N3G Project, an initiative to design new segmented high-purity germanium detectors while acquiring the technical expertise to build, manage, and maintain them independently. In this framework, the current paper offers a novel contribution. The innovative system designed to electrically connect the electrodes of the detector to the front-end electronics will be described and its low impact on the detector leakage current will be shown. Moreover, the architecture of a new integrated charge sensitive pre-amplifier will be reported and its validation will be presented. The circuit demonstrated excellent linearity and low noise. An integral non-linearity factor of $\mathbf{0. 4} \%$ was found and an optimum equivalent noise charge of 108 root-meansquare electrons was measured for a 15 pF equivalent electrode capacitance.

Examining the composition of aerosols in Antarctic ice cores can provide insights into past atmospheric circulation. However, interpreting this data requires an understanding of the characteristics and variability of present-day aerosols over time. In 2019, we performed the first year-round, multiparametric optical characterisation of atmospheric aerosols at Concordia Station in East Antarctica using OPTAIR, a novel instrument based on the Single Particle Extinction and Scattering (SPES) technique. We compared this data with the chemical composition of PM10 samples collected at the site and with meteorological data. We also compared it with synchronous data from a LIDAR and a ceilometer operating at Concordia Station. Significant temporal irregularities were observed in the atmospheric aerosol load, with more than one-third of the particles being dry-deposited during brief air mass subsidence events (‘spikes’), which mainly occurred in winter. The aerosol particles detected during these events were primarily composed of sea salt. Their optical properties differ significantly depending on whether they originate from frost flowers or the open ocean. Due to the intermittent nature of aerosol advection to Antarctica and its radiative effect, we estimate that glaciological, time-integrated samples may lead to an overestimation of light extinction by a factor of 3.5 or more.

The ^46Ar(^3He,d)^47K reaction was performed in inverse kinematics using a radioactive ^46Ar beam produced by the SPIRAL1 facility at GANIL and a cryogenic ^3He target. The AGATA-MUGAST-VAMOS setup allowed the coincident measurement of the γ rays, deuterons and recoiling ^47K isotopes produced by the reaction. The relative cross sections towards the proton-addition states in ^47K point towards a depletion of the πs_1/2 shell. The experimental findings are in good agreement with ab initio calculations, which predict that ^46Ar exhibits a charge density bubble associated with a pronounced proton closed-shell character.

We present the first measurement of the ^{47}K(d,pγ)^{48}K transfer reaction, performed in inverse kinematics using a reaccelerated beam of ^{47}K. The level scheme of ^{48}K has been greatly extended, with nine new bound excited states identified and spectroscopic factors deduced. Uniquely, the ^{47}K(d,p) reaction gives access to nuclear states that are sensitive to the interaction of protons and neutrons in the widely spaced 1s and fp orbitals, respectively. Detailed comparisons with SDPF-U and SDPF-MU shell-model calculations reveal a number of discrepancies between theory and experiment. Intriguingly, a systematic overestimation of spectroscopic factors and a poor reproduction of the energies for 1^{-} states suggests that the mixing between the πs_{1/2}^{1}d_{3/2}^{4} and πs_{1/2}^{2}d_{3/2}^{3} proton configurations in ^{48}K is not correctly described using current interactions, challenging our description of light nuclei around the N=28 island of inversion.

The FAMU experiment at RIKEN-RAL is a muonic atom experiment with the aim to determine the Zemach radius of the proton by measuring the 1s hyperfine splitting in muonic hydrogen. The activity of the FAMU Collaboration in the years 2015-2023 enabled the final optimisation of the detector-target setup as well as the gas working condition in terms of temperature, pressure and gas mixture composition. The experiment has started its data taking in July 2023. The status of the detector setup for the 2023 experimental runs, for the beam characterisation and muonic X-ray detection in the 100-200 keV energy range, is presented and discussed.

A search for full energy depositions from bosonic keV-scale dark matter candidates of masses between 65 keV and 1021 keV has been performed with data collected during Phase II of the GERmanium Detector Array (GERDA) experiment. Our analysis includes direct dark matter absorption as well as dark Compton scattering. With a total exposure of 105.5 kg yr, no evidence for a signal above the background has been observed. The resulting exclusion limits deduced with either Bayesian or Frequentist statistics are the most stringent direct constraints in the major part of the 140-1021 keV mass range. As an example, at a mass of 150 keV the dimensionless coupling of dark photons and axion-like particles to electrons has been constrained to $\alpha$'/$\alpha$ < 8.7x10$^{-24}$ and g$_{ae}$ < 3.3x10$^{-12}$ at 90% credible interval (CI), respectively. Additionally, a search for peak-like signals from beyond the Standard Model decays of nucleons and electrons is performed. We find for the inclusive decay of a single neutron in $^{76}$Ge a lower lifetime limit of $\tau_n$ > 1.5x10$^{24}$ yr and for a proton $\tau_p$ > 1.3x10$^{24}$ yr at 90% CI. For the electron decay e$^-\rightarrow\nu_e\gamma$ a lower limit of $\tau_e$ > 5.4x10$^{25}$ yr at 90% CI has been determined.

The distributed capacitive coupling of high -valued resistors with ground planes modifies their effective impedance and power spectral density of noise, especially at high frequency. This effect is clearly visible in poly -silicon resistors inside integrated circuits. When such resistors are used in the feedback network of Charge Sensitive Pre -amplifiers an excess noise arises with a non-white noise spectral density. The effect is a worsening of the spectroscopic resolution. The relevance of such effect with respect to the conventional noise sources is discussed in different practical cases.

The higher counting -rate and radiation hardness required by modern gamma spectroscopy experiments highlight the need for a new generation of High -Purity Germanium detectors based on electrons -collecting electrodes. To achieve this goal, new doping technologies are required. The one studied by the N3G (Next Generation Germanium Gamma detectors) project is the Pulsed Laser Melting. Besides the development of innovative segmented High -Purity Germanium crystals, the project is also aimed at developing a detector case complete of contact structures and front-end electronics. A specific integrated circuit pre -amplifier is being designed: a first version was tested at room temperature, using a pulser as pre -amplifier input. A resolution of 1.08 keV with 15 pF input capacitance, reproducing the one of a detector single segment, was obtained with 6 its shaping time.

The Advanced GAmma Tracking Array (AGATA) has been installed at Laboratori Nazionali di Legnaro (LNL), Italy. In this installation, AGATA will consist, at the beginning, of 13 AGATA triple clusters (ATCs) with an angular coverage of 1π, and progressively the number of ATCs will increase up to a 2π angular coverage. This setup will exploit both stable and radioactive ion beams delivered by the Tandem–PIAVE-ALPI accelerator complex and the SPES facility. The new implementation of AGATA at LNL will be used in two different configurations, firstly one coupled to the PRISMA large-acceptance magnetic spectrometer and lately a second one at Zero Degrees, along the beam line. These two configurations will allow us to cover a broad physics program, using different reaction mechanisms, such as Coulomb excitation, fusion-evaporation, transfer and fission at energies close to the Coulomb barrier. These setups have been designed to be coupled with a large variety of complementary detectors such as charged particle detectors, neutron detectors, heavy-ion detectors, high-energy γ-ray arrays, cryogenic and gasjet targets and the plunger device for lifetime measurements. We present in this paper the conceptual design, characteristics and performance figures of this implementation of AGATA at LNL.

The excited states of unstable ^{20}O were investigated via γ-ray spectroscopy following the ^{19}O(d,p)^{20}O reaction at 8  AMeV. By exploiting the Doppler shift attenuation method, the lifetimes of the 2_{2}^{+} and 3_{1}^{+} states were firmly established. From the γ-ray branching and E2/M1 mixing ratios for transitions deexciting the 2_{2}^{+} and 3_{1}^{+} states, the B(E2) and B(M1) were determined. Various chiral effective field theory Hamiltonians, describing the nuclear properties beyond ground states, along with a standard USDB interaction, were compared with the experimentally obtained data. Such a comparison for a large set of γ-ray transition probabilities with the valence space in medium similarity renormalization group ab initio calculations was performed for the first time in a nucleus far from stability. It was shown that the ab initio approaches using chiral effective field theory forces are challenged by detailed high-precision spectroscopic properties of nuclei. The reduced transition probabilities were found to be a very constraining test of the performance of the ab initio models.

Background: The Xe isotopic chain with four valence protons above the Z = 50 shell closure is an ideal laboratory for the study of the evolution of nuclear deformation. At the N = 82 shell closure, 136Xe presents all characteristics of a doubly closed shell nucleus with a spherical shape. In the very neutron-deficient isotopes close to N = 50, the alpha-decay chain of Xe was investigated to probe the radioactive decay properties near the drip-line and the magicity of 100Sn. Additionally, the Xe isotopes present higher order symmetries in the nuclear deformation such as the octupole degree of freedom near N = 60 and N = 90 or O(6) symmetry in stable isotopes.Purpose: The relevance of the O(6) symmetry has been investigated by measuring the spectroscopic quadrupole moment of the first excited states in 124Xe. In the O(6) symmetry limit, the spectroscopic quadrupole moment of collective states is expected to be null.Method: A stable 124Xe beam with energies of 4.03A MeV and 4.11A MeV was used to bombard a natW target at the GANIL facility. Excited states were populated via the safe Coulomb excitation reaction. The collision of the heavy ions with a large Z at low energy make this reaction sensitive to the diagonal E2 matrix element of the excited states. The recoils were detected in the VAMOS++ magnetic spectrometer and the gamma rays in the AGATA tracking array. The least squares fitting code GOSIA was used for the analysis to extract both E2 and M1 transitional and E2 diagonal matrix elements.Results: The rotational ground state band was populated up to the 8+1 state as well as the 2+2 and 4+2 states. Using high precision spectroscopic data to constrain the GOSIA fit, the spectroscopic quadrupole moments of the 2+1 , 4+1 , and 6+1 states were determined for the first time. Conclusions: The spectroscopic quadrupole moments were found to be negative, large, and constant in the ground state band underlining the prolate axially deformed ground state band of 124Xe. The present experimental data confirm that the is broken in 124Xe.

The ability to detect liquid argon scintillation light from within a densely packed high-purity germanium detector array allowed the GERDA experiment to reach an exceptionally low background rate in the search for neutrinoless double beta decay of ^76Ge. Proper modeling of the light propagation throughout the experimental setup, from any origin in the liquid argon volume to its eventual detection by the novel light read-out system, provides insight into the rejection capability and is a necessary ingredient to obtain robust background predictions. In this paper, we present a model of the GERDA liquid argon veto, as obtained by Monte Carlo simulations and constrained by calibration data, and highlight its application for background decomposition.

We present the measurement of the two-neutrino double-β decay rate of ^{76}Ge performed with the GERDA Phase II experiment. With a subset of the entire GERDA exposure, 11.8 kg yr, the half-life of the process has been determined: T_{1/2}^{2ν}=(2.022±0.018_{stat}±0.038_{syst})×10^{21}  yr. This is the most precise determination of the ^{76}Ge two-neutrino double-β decay half-life and one of the most precise measurements of a double-β decay process. The relevant nuclear matrix element can be extracted: M_{eff}^{2ν}=(0.101±0.001).

The Zirconium (Z = 40) isotopic chain has attracted interest for more than four decades. The abrupt lowering of the energy of the first 2^+ state and the increase in the transition strength B(E2; 2^+_1→ 0^+_1) going from ^98 Zr to ^100 Zr has been the first example of “quantum phase transition” in nuclear shapes, which has few equivalents in the nuclear chart. Although a multitude of experiments have been performed to measure nuclear properties related to nuclear shapes and collectivity in the region, none of the measured lifetimes were obtained using the Recoil Distance Doppler Shift method in the γγ -coincidence mode where a gate on the direct feeding transition of the state of interest allows a strict control of systematical errors. This work reports the results of lifetime measurements for the first yrast excited states in ^98-104 Zr carried out to extract reduced transition probabilities. The new lifetime values in γγ -coincidence and γ -single mode are compared with the results of former experiments. Recent predictions of the Interacting Boson Model with Configuration Mixing, the Symmetry Conserving Configuration Mixing model based on the Hartree–Fock–Bogoliubov approach and the Monte Carlo Shell Model are presented and compared with the experimental data.

The article gives the motivations for the measurement of the hyperfine splitting (hfs) in the ground state of muonic hydrogen to explore the properties of the proton at low momentum transfer. It summarizes these proposed measurement methods and finally describes the FAMU experiment in more detail.

The AGATA collaboration has a long-standing leadership in the development of front-end electronics for high resolution γ -ray spectroscopy using large volume high purity germanium detectors. For two decades, the AGATA collaboration has been developing state-of-the-art digital electronics processing with high resolution sampling ADC, high-speed signal transfer and fast readout to a high throughput computing (HTC) farm for on-line pulse shape analysis. The collaboration is presently addressing the next challenge of equipping a 4 π array with more than 6000 channels in high resolution mode, generating approximately 10 MHz of total trigger requests, coupled to a large variety of complementary instruments. A next generation of front-end electronics, presently under design, is based on industrial products (System on Module FPGA’s), has higher integration and lower power consumption. In this contribution, the conceptual design of the new electronics is presented. The results of the very first tests of the pre-production electronics are presented as well as future perspectives.

Classical novae are thermonuclear explosions in stellar binary systems, and important sources of 26 Al and 22 Na. While γ rays from the decay of the former radioisotope have been observed throughout the Galaxy, 22 Na remains untraceable. Its half-life (2.6 yr) would allow the observation of its 1.275 MeV γ -ray line from a cosmic source. However, the prediction of such an observation requires good knowledge of its nucleosynthesis. The 22 Na( p , γ ) 23 Mg reaction remains the only source of large uncertainty about the amount of 22 Na ejected. Its rate is dominated by a single resonance on the short-lived state at 7785.0(7) keV in 23 Mg. Here, we propose a combined analysis of particle-particle correlations and velocity-difference profiles to measure femtosecond nuclear lifetimes. The application of this method to the study of the 23 Mg states, places strong limits on the amount of 22 Na produced in novae and constrains its detectability with future space-borne observatories.

Abstract We search for tri-nucleon decays of $$^{76}$$ 76 Ge in the dataset from the GERmanium Detector Array (GERDA) experiment. Decays that populate excited levels of the daughter nucleus above the threshold for particle emission lead to disintegration and are not considered. The ppp-, ppn-, and pnn-decays lead to $$^{73}$$ 73 Cu, $$^{73}$$ 73 Zn, and $$^{73}$$ 73 Ga nuclei, respectively. These nuclei are unstable and eventually proceed by the beta decay of $$^{73}$$ 73 Ga to $$^{73}$$ 73 Ge (stable). We search for the $$^{73}$$ 73 Ga decay exploiting the fact that it dominantly populates the 66.7 keV $$^{73m}$$ 73 m Ga state with half-life of 0.5 s. The nnn-decays of $$^{76}$$ 76 Ge that proceed via $$^{73m}$$ 73 m Ge are also included in our analysis. We find no signal candidate and place a limit on the sum of the decay widths of the inclusive tri-nucleon decays that corresponds to a lower lifetime limit of 1.2 $$\times $$ × 10 $$^{26}$$ 26 yr (90% credible interval). This result improves previous limits for tri-nucleon decays by one to three orders of magnitude.

In this work, both a theoretical study and experimental measurements are shown to describe the equivalent noise charge (ENC) contribution of the parallel $\sqrt {f}$ noise of a charge-sensitive preamplifier in a nuclear spectroscopic chain. Previous works have demonstrated that this noise is produced by the distributed capacitive coupling to bulk of the preamplifiers’ high-valued feedback resistors, which give rise to an resistive-capacitive (R-C) structure known in the literature as “diffusive line.” The introduced noise is particularly evident when such devices are integrated in a chip using a polysilicon layer that has intrinsically high distributed capacitance to the chip’s bulk. Different shaping amplifiers are taken into consideration (analog quasi-Gaussian, digital trapezoidal/triangular, and CR-RCn), and closed-form expressions of noise coefficients are given whenever possible.