Search

The present work is inherent to the NUMEN project that aims at providing data-driven information for the nuclear matrix elements of the neutrinoless double beta decay through the study of heavy-ion induced double charge exchange reactions. This is a formidable task since during a nuclear collision, the same final states may be populated through various reaction mechanisms. In this respect, understanding the degree of competition between successive nucleon transfer and charge exchange reactions is crucial for the proper description of the meson-exchange mechanism. To this purpose, the reaction dynamics in the 18O+48Ti collision were sought by measuring a plethora of reaction channels under the same experimental conditions. The 48Ti was chosen as target since it is the daughter nucleus of 48Ca in double beta decay. The relevant experiment was performed at the MAGNEX facility of INFN-LNS in Catania. In this contribution, the status of the analysis for the 48Ti(18O,18F)48Sc single charge exchange reaction will be presented.

The search for neutrino-less double beta decay has attracted much interest in the last years due to the extraordinary consequences that could derive from its observation. In the view to provide experimental information on the nuclear matrix elements involved in the expression of neutrino-less double beta decay half-life, the NUMEN project is measuring cross-sections of double charge exchange and other quasi-elastic nuclear reactions using the MAGNEX magnetic spectrometer. In particular, the newly proposed multichannel approach, applied both to the experimental and theoretical analysis, will be discussed.

The experimental setup of the new measurement of 239Pu fission and capture cross-section in the n_TOF time-of-flight facility at CERN is presented. The measurement aims to address the needs and demands of nuclear data users. The experiment incorporates an innovative fast Fission Fragment Detector and the n_TOF Total Absorption Calorimeter, enabling the implementation of the fission tagging technique. Preliminary results exhibit the robust performance of the detector systems, along with the high quality of the new 239Pu samples. These samples were exclusively produced for this measurement by the European Commission’s Joint Research Centre in Geel.

The study of a network of nuclear reactions populated in the 18O + 12C collision is the main topic of the present paper. It was performed to test nuclear structure and reaction theories in describing the full reaction mechanism occurring in the (18O, 18F) single charge exchange nuclear reaction. From the experimental side, an 18O beam was produced at 275 MeV incident energy by the K800 superconducting cyclotron and the MAGNEX magnetic spectrometer was used at the Laboratori Nazionali del Sud of the Istituto Nazionale di Fisica Nucleare to momentum analyse the ejectiles produced in the nuclear reactions within the same experimental setup. From the theoretical side, the proposed approach consists of analysing the whole network of nuclear reactions in the framework of a unique comprehensive and coherent theoretical calculation. This holistic approach, applied both to the experimental and theoretical analysis, is the main feature and novelty of the work presented here.

In the framework of the H2020 CLEANDEM project, a small robotic vehicle was equipped with a series of different sensors that were developed for the preliminary inspection of areas possibly contaminated by radiation. Such unmanned inspection allows to identify dangerous locations prior to the possible start of human operations. One of the developed devices, named the MiniRadMeter, is a compact low-cost sensor that performs gamma and neutron radiation field mapping in the environment. The MiniRadMeter was successfully tested in a simulated field mission with four "hidden" radioactive sources and a neutron generator. In this work, we describe the test procedure and the results, which were supported by the outcome of dedicated Monte Carlo simulations. [ABSTRACT FROM AUTHOR]

The current scenario of radioactive waste management requires innovative and automated solutions to ensure its effectiveness and safety. In response to this need, the Proximity Imaging System for Sort and Segregate Operations (PI3SO) project was proposed. It is a gamma radiation proximity scanner system for radioactive waste with the primary goal of speeding up some aspects of the waste management cycle while reducing direct human operations. The system will provide proximity imaging for hot-spot finding and spectral analysis for radiological characterization, enabling semiautomatic recognition, sorting and separation of radioactive waste. The core of the proposed scanning system consists of an array of 128 CsI(Tl) scintillators, 1 cm3 size, coupled with silicon photomultipliers (SiPMs), installed on a motorized bridge sliding along a suitable table in order to scan the materials under investigation. [ABSTRACT FROM AUTHOR]

In the framework of the PI3SO project (Proximity Imaging System for Sort and Segregate Operations) funded by INFN-Energy project, aimed at the low and intermediate level radioactive waste (radwaste) classification, conditioning and characterization, a scanning system based on a set of 128 gamma-ray detectors based on CsI(Tl) crystal scintillators readout by a silicon photomultiplier have been built and characterized. These are arranged in linear arrays grouped in modules, each one being made of sixteen detection elements compose a sensitive unit, named module, and eight modules define the full-scintillators scanning system. The combination of four modules, arranged in a linear configuration, defines a sliding linear array named detection unit. Placed one above a scanning table and the other parallel to it underneath the table, the two co-moving detection units detect gamma-rays from sparse objects on table improving the detection of partially gamma sources and they will identify the hot-spot. The described modules are suitable for the sorting of nuclear materials and can be used as scanner of radioactive objects placed on a large area surface. Each unit was tested with point-like laboratory gamma-ray 137Cs and 22Na source: the results are promising in view of the integration with the mechanical system which will move the detection units scanning the radwaste. Next step are planned tests in a real environment.

In the framework of the MICADO project, funded by Euratom H2020 program, a system of gamma ray and neutron counters was developed. These counters are meant to be deployed as a monitoring grid around radwaste drums in low and/or intermediate waste storage sites, even though they could be usefully employed also for high level waste. A prototype of the MICADO gamma and neutron monitoring grid was installed and tested around real radwaste drums in two storage sites on the ORANO and NUCLECO premises, at La Hague and Casaccia respectively. A modular support structure, was assembled in four units in order to accommodate four radwaste drums. Each support unit hosted four gamma ray counters and four neutron counters. In both cases the units were installed around four radwaste drums also containing small or tiny quantities of actinides, and data were acquired. The results are quite promising as the system behaved as expected from previous tests and from the nominal radiological info about the drums.

Neutron cross section measurements are often made relative to a neutron cross section standard. Thus, the accuracy of the neutron standards determines the best possible accuracy of the neutron measurements. The 235U(n,f) cross section is widely used as reference, while it is considered a standard at thermal point and between 0.15 to 200 MeV. For this reason, additional cross section data for the 235U(n,f) reaction are useful in order to improve the accuracy and to extend the energy range of the standard. In this work, preliminary results of the measurement of the 235U(n,f) cross-section relative to the standard 10B(n,a) reaction are presented. The high accuracy measurement was performed at the experimental area EAR-1 of the n_TOF facility at CERN, aiming at covering the energy range from the thermal region up to approximately 100 keV. The samples were produced at JRC-Geel in Belgium, while the experimental setup was based on Micromegas detectors.

In the framework of the PREDIS EU project, a wireless battery-operated gamma-ray detection system was developed in order to provide a medium-to-long-term monitoring system for radioactive waste drums. It was initially proposed to monitor the gamma radioactivity outcoming from steel drums containing cemented radwaste, even though it could be usefully employed in a wider range of applications. Gamma rays are penetrating and convey information from the drum's internal structure, as the count rate measured on the surface depends on the thickness and density of the crossed materials. A number of sensors arranged around a drum, typically four units, provide indications of the emission anisotropy, and any sensitive change in the measured count rate would hint at some anomaly, thus triggering a suitable inspection by operators. [ABSTRACT FROM AUTHOR]

The shortage of 3 He, a crucial element widely used as a neutron converter in neutron detection applications, has sparked significant research efforts aimed at finding alternative materials, developing appropriate deposition methods, and exploring new detector architectures. This issue has required the exploration of novel approaches to address the challenges faced in neutron detection. Among the available conversion materials, 10 B has emerged as one of the most promising choices due to its high neutron-capture cross-section and relatively high Q value. In our previous papers, we delved into the possibility of depositing neutron conversion layers based on 10 B using Pulsed Laser Deposition (PLD). We investigated and evaluated the performance of these layers based on various factors, including deposition conditions, substrate properties, and film thickness. Moreover, we successfully developed and tested a device that employed a single conversion layer coupled with a silicon particle detector. In this current study, we present the development of a new device that showcases improved performance in terms of efficiency, sensitivity, and discrimination against γ background signals. The background signals can arise from the environment or be associated with the neutron field. To achieve these advancements, we considered a new detection geometry that incorporates the simultaneous use of two 10 B conversion layers, each with a thickness of 1.5 μ m, along with two solid-state silicon detectors. The primary objective of this design was to enhance the overall detection efficiency when compared to the single-layer geometry. By employing this novel setup, our results demonstrate a significant enhancement in the device's performance when exposed to a neutron flux from an Am-Be neutron source, emitting a flux of approximately 2.2 × 10 6 neutrons per second. Furthermore, we established a noteworthy agreement between the experimental data obtained and the simulation results. [ABSTRACT FROM AUTHOR]

The NUMEN experimental activity with accelerated beams is performed at INFN–Laboratori Nazionali del Sud (LNS) in Catania using the Superconducting Cyclotron and the MAGNEX magnetic spectrometer. The scientific motivation of NUMEN is to extract experiment-driven information on the nuclear matrix elements entering in the expression of the 0νββ decay half-life. The reaction cross sections involved, especially for the double charge exchange process, are very low, thus limiting the present exploration to a few selected isotopes of interest in the context of typically low-yield experimental runs. In order to make feasible a systematic study of all the candidate nuclei, a major upgrade of the LNS facility is foreseen to increase the experimental yield by more than two orders of magnitude. To this purpose, frontier technologies are being developed for the accelerator and the detection systems. An updated description of the choices derived from the recent R&D activity on the target system and MAGNEX focal plane detector is given.

The possibility to use a special class of heavy-ion induced direct reactions, such as double charge exchange reactions, is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The strategies adopted in the experimental campaigns performed at INFN - Laboratori Nazionali del Sud are briefly described, emphasizing the advantages of the multi-channel approach to nuclear reaction data analysis.

In the framework of the MICADO (Measurement and Instrumentation for Cleaning And Decommissioning Operations) European Union (EU) project, aimed at the full digitization of low and intermediate-level radioactive waste (radwaste) management, a set of 32 solid state thermal neutron detectors, named SiLiF, and 36 gamma-ray counters based on a scintillating fiber readout at each end by a silicon photomultiplier, named SciFi, have been built and characterized. MICADO project encompasses a complete active and passive characterization of the radwaste drums with neutrons and gamma rays, followed by a longer-term monitoring phase. The detectors described are suitable for the monitoring of nuclear materials and can be used around radioactive waste drums possibly containing small quantities of actinides, as well as around spent fuel casks in interim storage or during transportation. Suitable polyethylene moderators, for the SiLiF detectors, can be exploited to better shape the detector response to the expected neutron spectrum, according to Monte Carlo simulations that were performed. The SciFi detectors were thoroughly tested with a 22Na and a 137Cs gamma-ray sources. Both detectors described were tested with an intense AmBe source of neutron and gamma ray. The results are satisfactory and show a quite uniform and reproducible behavior. The next step will be the test in a real environment.

Experiments performed on Storage Rings have shown that lifetimes of beta-radionuclides can change dramatically as a function of theionization state. PANDORA (Plasmas for Astrophysics, Nuclear Decay Observation and Radiation for Archaeometry) aims at measuring, for the first time, nuclear β-decay rates in stellar-like conditions, especially for radionuclides involved in nuclear-astrophysics processes (BBN, s- processing, CosmoChronometers, Early Solar System formation). Compact magnetic plasma traps, where plasmas reach density ne~10n-1014 cm-3, and temperature Te~0.1-30 keV, are suitable for such studies. The decay rates can be measured as a function of the charge state distribution of the inplasma ions. The collaboration is now designing the plasma trap able to reach the needed plasma densities, temperatures and charge states distributions. A first list of radioisotopes, including tens of physics cases of potential interest is now available. Possible physics cases include, among the others, 2°4Tl, 63Ni, 6°Co, 171Tm, 147Pm, 85Kr, 176Lu and the pairs 187Re-187Os and 87Sr-87Rb, which play a crucial role as cosmo-clock. Physics cases are now under evaluation in terms of lifetime measurements feasibility in a plasma trap.

The possibility to use a special class of heavy-ion induced direct reactions, such as double charge exchange reactions, is discussed in view of their application to extract information that may be helpful to determinate the nuclear matrix elements entering in the expression of neutrinoless double beta decay half-life. The methodology of the experimental campaign presently running at INFN - Laboratori Nazionali del Sud is reported andthe experimental challenges characterizing such activity are described.

Several methods to detect thermal neutrons make use of the naturally occurring 6Li isotope, as it has a rather high cross-section for neutron capture followed by a decay into an alpha particle and a triton. Due to the high chemical reactivity of lithium, the use of the stable isotopic salt 6LiF is generally preferred to the pure 6Li. The typical method for depositing thin layers of 6LiF on suitable substrates, therefore creating so-called neutron converters, is evaporation under vacuum. The evaporation technique, as well as a newly developed chemical deposition process, are described along with their benefits and drawbacks, and the results of neutron detection tests performed with the two types of converters coupled to silicon diodes show convenient performances. [ABSTRACT FROM AUTHOR]

The demand for new thermal neutron detectors as an alternative to 3He tubes in research, industrial, safety and homeland security applications, is growing. These needs have triggered research and development activities about new generations of thermal neutron detectors, characterized by reasonable efficiency and gamma rejection comparable to 3He tubes. In this paper we show the state of art of a promising lowcost technique, based on commercial solid state silicon detectors coupled with thin neutron converter layers of 6LiF deposited onto carbon fiber substrates. Several configurations were studied with the GEANT4 simulation code, and then calibrated at the PTB Thermal Neutron Calibration Facility. The results show that the measured detection efficiency is well reproduced by the simulations, therefore validating the simulation tool in view of new designs. These neutron detectors have also been tested at neutron beam facilities like ISIS (Rutherford Appleton Laboratory, UK) and n_TOF (CERN) where a few samples are already in operation for beam flux and 2D profile measurements. Forthcoming applications are foreseen for the online monitoring of spent nuclear fuel casks in interim storage sites.