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In this work, we propose a prototype of a compact detector assembly capable of discriminating between neutrons and gamma rays, by performing pulse shape analysis. The device takes advantage of recent improvements in silicon photomultiplier (SiPM) technology and the excellent neutron/gamma-ray discrimination capabilities of new plastics and standard liquid scintillators. Our work is focused on the read-out of small-, medium-, and large-sized organic scintillators with large-area SiPM arrays ($4 \times 4$ NUV and RGB-SiPM arrays, 17 mm $\times$ 17 mm). In particular, we used EJ-276 (and its old version EJ-299) and EJ-276G plastic scintillators of several sizes (ranging from 20- to 50-mm diameter) and two large liquid scintillator cells (EJ-301 and EJ-309, 50 mm diameter $\times 50$ mm thickness). Moreover, we show the comparison of neutron/gamma-ray discrimination performance between SiPM and standard photomultiplier read-out configurations. The presented innovative device could be used in different fields, first in fundamental nuclear physics experiments, as an ancillary neutron detector for the active target at the selective production of exotic species (SPES) facility at the Legnaro National Laboratories in Italy. Additionally, it could be used in radiation monitoring applications, as a fast neutron/gamma-ray counter to be embedded in unmanned vehicles for radiation monitoring. [ABSTRACT FROM AUTHOR]

The dark matter interpretation of the DAMA/LIBRA annual modulation signal represents a long-standing open question in astroparticle physics. The SABRE experiment aims to test such claim, bringing the same detection technique to an unprecedented sensitivity. Based on ultra-low background NaI(Tl) scintillating crystals like DAMA, SABRE features a liquid scintillator Veto system, surrounding the main target, and it will deploy twin detectors: one in the Northern hemisphere at Laboratori Nazionali del Gran Sasso (LNGS), Italy and the other in the Stawell Underground Physics Laboratory (SUPL), Australia, first laboratory of this kind in the Southern hemisphere. The first very-high-purity crystal produced by the collaboration was shipped to LNGS in 2019 for characterization. It features a potassium contamination, measured by mass spectroscopy, of the order of 4 ppb, about three times lower than DAMA/LIBRA crystals. The first phase of the SABRE experiment is a Proof-of-Principle (PoP) detector featuring one crystal and a liquid scintillator Veto, at LNGS. This contribution will present the results of the stand-alone characterization of the first SABRE high-purity crystal, as well as the status of the PoP detector, commissioned early in the summer of 2020. [ABSTRACT FROM AUTHOR]

Abstract The use of passive and active interrogation techniques to evaluate materials concerning their content of special nuclear materials (SNM) is fundamental in fields such as nuclear safeguards and security. Detection of fast neutrons and γ rays, which are a characteristic signature of SNM, has several potential advantages compared with the commonly used systems based on thermal and epithermal neutron counters, the most important being the much shorter required coincidence times and the correspondingly reduced rate of background events due to accidental coincidences. Organic scintillators are well suited for this purpose due to their fast timing properties and composition being based on carbon and hydrogen with large elastic scattering cross-sections for fast neutrons. Organic scintillators also have suitable detection efficiency for γ rays and exhibit pulse shape properties which are favorable for distinguishing between neutrons and γ rays. This paper presents experimental results and Monte Carlo simulations for a neutron–neutron and γ -neutron coincidence detection setup for identification and characterization of SNM based on such detectors. The measurements were carried out on different samples of PuO 2 material with varying content of 240Pu at the Joint Research Center (JRC) of the European Commission, Ispra, Italy. The results demonstrate significant advantages of fast neutron- γ coincidence detection over fast neutron–neutron coincidence counting for certain applications, e.g. for nuclear security systems, even in the presence of moderate amounts of shielding. [ABSTRACT FROM AUTHOR]

Abstract: This paper describes the procurement and the production quality control system of Pseudocumene, the scintillator solvent of the solar neutrino detector Borexino at the Laboratorio Nazionale del Gran Sasso (Italy). This material constitutes about 99.9% of the scintillator total mass, therefore being the most critical element for the radiopurity of the detector. [Copyright &y& Elsevier]

The use of NE102A-BaF2 phoswich detector drastically improves the particle identification with respect to BaF2 crystals. To better exploit the possibility of light ion discrimination we have applied digital signal processing to the signals, on-beam collected with NE102A-BaF2 phoswich. We present the results obtained for the heavy ion charge identification (up to Z = 50) and light particle mass identification, using digital pulse shape acquisition and a 12-bit, 2 GSample/s sampling analog to digital converter. The results concerning the response of BaF2 -plastic phoswich to the reaction products issued at forward angles in the collision of 35.1 MeV/u 124Sn beam on 64Ni target have been obtained at the Superconducting Cyclotron of the Laboratori Nazionali del Sud in Catania. [ABSTRACT FROM AUTHOR]

Abstract: Double beta processes in 64Zn, 70Zn, 180W, and 186W have been searched for with the help of large volume (0.1–0.7 kg) low background ZnWO4 crystal scintillators at the Gran Sasso National Laboratories of the INFN (Italy). The total measurement time exceeds ten thousand hours. New improved half-life limits on double electron capture and electron capture with positron emission in 64Zn have been set, in particular (all the limits are at 90% C.L.): , , and . In addition, new bounds were set for different modes of 2β processes in 70Zn, 180W, and 186W at the level of 1017–1020 yr. [Copyright &y& Elsevier]

At the Department of Physics of the University of Pisa, Italy, a new and fully engineered version of the YAP-(S)PET small animal scanner has been recently installed. The new YAP-(S)PET is able to perform both PET and SPECT studies on small animals. The scanner is made up of four heads: each one is composed of a 4 × 4 cm² YAIO3:Ce (or YAP:Ce) matrix of 20 × 20 elements, 2 × 2 × 25 mm³ each, coupled to a Position Sensitive Photomultiplier (PS-PMT) (Hamamatsu R2486). The four modules are positioned on a rotating gantry. The switching to the SPECT modality is easily made by mounting a high resolution parallel hole (0.6 mm ⊘, 0.15 mm septum) lead collimator in front of each crystal. This paper reports the performance of the system in terms of absolute sensitivity and spatial resolution for both PET and SPECT modalities. The scatter fraction and noise-equivalent count rate (NEC) for a mouse phantom for different energy windows have been measured in PET modality. Images of phantoms and animals are also presented. [ABSTRACT FROM AUTHOR]

Residual radioactive contaminants of a caesium hafnium chloride (Cs 2 HfCl 6) crystal scintillator have been measured in a low background setup at the Gran Sasso National Laboratory of the INFN, Italy. The total alpha activity of the detector is at the level of 7.8(3) mBq/kg. The results of direct studies of the α decay of naturally occurring Hf isotopes that have been performed using the "source=detector" approach are presented. In 2848 h of data taking, the α decay of 174Hf was observed with T = 1 / 2 (7.0 ± 1.2) × 10 16 y. [ABSTRACT FROM AUTHOR]

Borexino, a real-time device for low energy neutrino spectroscopy, has completed the construction phase at the middle of 2006 in the Underground Laboratories at Gran Sasso, Italy. The detector has been filled with 1300 tons of highly purified scintillator and 2600 tons of ultrapure water as external shield and, since May 16th, 2007, is under data taking. The experimental goal, the direct measurement of flux of 7Be solar neutrinos of all flavour via neutrino-electron scattering in an ultrapure scintillator liquid, has been achieved and further measurements (PP, PeP, CNO neutrinos, geoneutrinos, supernova) are object of future results. The paper describes the purification methods adopted in Borexino, to achieve unique and unprecedented results on the scintillator purity. Requirements and purification methods will be reported [ABSTRACT FROM AUTHOR]

Reports on the appointment of Eugenio Coccia as director of the Gran Sasso National Laboratory in the Apennines, northeast of Rome, Italy. Controversies concerning the safety of the underground laboratory; Problems faced by the laboratory management team in relation to the scintillator leak from the laboratory.

Abstract: During the course of 2009, in the framework of a project supported by the National Institute of Nuclear Physics, a number of tests were carried out at the Department of Physics of the University of Bologna in order to achieve a good quality CT scan of the internal human ear. The work was carried out in collaboration with the local “S. Orsola” Hospital in Bologna and a company (CEFLA) already involved in the production and commercialization of a CT scanner dedicated to dentistry. A laboratory scanner with a simple concept detector (CCD camera-lens-mirror-scintillator) was used to see to what extent it was possible to enhance the quality of a conventional CT scanner when examining the internal human ear. To test the system, some conventional measurements were made, such as the spatial resolution calculation with the MTF and dynamic range evaluation. Different scintillators were compared to select the most suitable for the purpose. With 0.5mm thick structured cesium iodide and a field of view of 120×120mm2, a spatial resolution of 6.5lp/mm at 5% MTF was obtained. The CT of a pair of human head phantoms was performed at an energy of 120kVp. The first phantom was a rough representation of the human head shape, with soft tissue made of coarse slabs of Lucite. Some inserts, like small aluminum cylinders and cubes, with 1mm diameter drilled holes, were used to simulate the channels that one finds inside the human inner ear. The second phantom is a plastic PVC fused head with a real human cranium inside. The bones in the cranium are well conserved and the inner ear features, such as the cochlea and semicircular channels, are clearly detectable. After a number of CT tests we obtained good results as far as structural representation and channel detection are concerned. Some images of the 3D rendering of the CT volume are shown below. The doctors of the local hospital who followed our experimentation expressed their satisfaction. The CT was compared to a virtual endoscopy and judged particularly useful for clinical pre-surgery diagnostics. The experimentation proceeds with a faster scanner now under development in our laboratories. We believe this work could be of a certain interest for the medical imaging world. [Copyright &y& Elsevier]