As quantum coherence times of superconducting circuits have increased from nanoseconds to hundreds of microseconds, they are currently one of the leading platforms for quantum information processing. ...However, coherence needs to further improve by orders of magnitude to reduce the prohibitive hardware overhead of current error correction schemes. Reaching this goal hinges on reducing the density of broken Cooper pairs, so-called quasiparticles. Here, we show that environmental radioactivity is a significant source of nonequilibrium quasiparticles. Moreover, ionizing radiation introduces time-correlated quasiparticle bursts in resonators on the same chip, further complicating quantum error correction. Operating in a deep-underground lead-shielded cryostat decreases the quasiparticle burst rate by a factor thirty and reduces dissipation up to a factor four, showcasing the importance of radiation abatement in future solid-state quantum hardware.
Background model of the CUPID-0 experiment Azzolini, O.; Beeman, J. W.; Bellini, F. ...
European physical journal. C, Particles and fields,
07/2019, Letnik:
79, Številka:
7
Journal Article
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CUPID-0 is the first large mass array of enriched Zn
82
Se scintillating low temperature calorimeters, operated at LNGS since 2017. During its first scientific runs, CUPID-0 collected an exposure of ...9.95 kg year. Thanks to the excellent rejection of
α
particles, we attained the lowest background ever measured with thermal detectors in the energy region where we search for the signature of
82
Se
neutrinoless double beta decay. In this work we develop a model to reconstruct the CUPID-0 background over the whole energy range of experimental data. We identify the background sources exploiting their distinctive signatures and we assess their extremely low contribution down to
∼
10
-
4
counts/(keV kg year) in the region of interest for
82
Se
neutrinoless double beta decay search. This result represents a crucial step towards the comprehension of the background in experiments based on scintillating calorimeters and in next generation projects such as CUPID.
Deltas are the locus of river-borne sediment accumulation, however, their role in sequestering plastic pollutants is still overlooked. By combining geomorphological, sedimentological, and geochemical ...analyses, which include time-lapse multibeam bathymetry, sediment provenance, and μFT-IR analyses, we investigate the fate of plastic particles after a river flood event providing an unprecedented documentation of the spatial distribution of sediment as well as of microplastics (MPs), including particles fibers, and phthalates (PAEs) abundances in the subaqueous delta. Overall sediments are characterized by an average of 139.7 ± 80 MPs/kg d.w., but display spatial heterogeneity of sediment and MPs accumulation: MPs are absent within the active sandy delta lobe, reflecting dilution by clastic sediment (ca. 1.3 Mm3) and sediment bypass. The highest MP concentration (625 MPs/kg d.w.) occurs in the distal reaches of the active lobe where flow energy dissipates. In addition to MPs, cellulosic fibers are relevant (of up to 3800 fibers/kg d.w.) in all the analyzed sediment samples, and dominate (94 %) with respect to synthetic polymers.
Statistically significant differences in the relative concentration of fiber fragments ≤0.5 mm in size were highlighted between the active delta lobe and the migrating bedforms in the prodelta. Fibers were found to slightly follow a power law size distribution coherent with a one-dimensional fragmentation model and thus indicating the absence of a size dependent selection mechanism during burial. Multivariate statistical analysis suggests traveling distance and bottom-transport regime as the most relevant factors controlling particle distribution. Our findings suggest that subaqueous prodelta should be considered hot spots for the accumulation of MPs and associated pollutants, albeit the strong lateral heterogeneity in their abundances reflects changes in the relative influence of fluvial and marine processes.
Display omitted
•River prodelta are pools of Microplastics (MPs), Phthalates, and cellulosic fibers•MP abundances were investigated based on morpho-bathymetry and flood occurrence•Lateral heterogeneity of MPs and cellulose fibers in Po River Podelta sediments are related to depositional processes•Sites contaminated by MPs are distal reaches of delta lobe and migrating bedforms with maximum concentration of 625 MPs/kg•A large abundance of cellulose fibers was found
.
Archaeological Roman lead (Pb) is known to be a suitable material for shielding experimental apparata in rare event searches. In the past years the intrinsic radiopurity of this material was ...investigated using different technologies. In this work we applied the latest advancements in cryogenic techniques to study the bulk radiopurity of a 1cm^3 sample of archaeological Roman Pb. We report the lowest ever measured limit on
210
Pb content in Roman Pb, with a concentration lower than 715μBq/kg. Furthermore, we also studied
238
U and
232
Th impurity concentrations. Our values concur with independent measurements reported in literature.
Abstract
Muonic atom X-ray Emission Spectroscopy (µ-XES) is a novel technique based on the detection of high-energy X-rays emitted after the interaction of a negative muon beam with matter. Thanks to ...the multi-elemental range, negligible self-absorption of the x-rays and the possibility of performing depth profile studies, the technique is a very powerful probe for the analysis of cultural heritage artefacts. By tuning the energy of the incident muon beam, indeed, it is possible to investigate the different layers that constitute a sample. In this work, we report preliminary results of the analysis on two fire-gilded surfaces, in which the data analysis is coupled with Monte Carlo-based simulation software. Here, to perform a depth profile characterization, the samples were analysed at different beam energies (or momentum). Each of the resulting x-ray spectra was then analysed and compared with the output of the simulations software and a remarkably good agreement was reached. The results of the work are promising and with this approach, it will be possible to enhance the capability offered by the technique, both in terms of data analysis and data interpretation.
In low background experiments the reduction of all possible radioactive contaminants is a crucial point for detector construction. This is also true for the surface contaminants, either those ...introduced during the production of detector components or those introduced during handling, treatment or storage. One of the most critical issue in this field is the control of the contamination induced by
222
Rn and its progenies in the environment where the detectors are assembled and stored. Radioactive atoms can stick on detector components and create a net increase of the contaminants present on their surfaces, introducing an additional—often not negligible—source of background. The reduction of this kind of contaminations can become of primary importance in the case of fully sensitive devices, like cryogenic particle detectors. In this paper the analysis on the Rn sticking factor for copper and tellurium dioxide—the two main materials used for the construction of the CUORE detector—is discussed. The diffusion of radioactive atoms inside the detector components is considered in order to evaluate the effective contribution of Rn exposure to the background counting rate of an experiment.
The FAMU experiment aims to measure for the first time the hyperfine splitting of the muonic hydrogen ground state. From this measurement the proton Zemach radius can be derived and this will shed ...light on the determination of the proton charge radius. In this paper, we describe the scientific goal, the method and the detailed preparatory work. This includes the outcome of preliminary measurements, subsequent refined simulations and the evaluation of the expected results. The experimental setup being built for the measurement of the hyperfine splitting to be performed at the RAL laboratory muon facility is also described.
The CUPID-0 experiment searches for double beta decay using cryogenic calorimeters with double (heat and light) read-out. The detector, consisting of 24 ZnSe crystals 95 Formula omitted enriched in ...Formula omittedSe and two natural ZnSe crystals, started data-taking in 2017 at Laboratori Nazionali del Gran Sasso. We present the search for the neutrino-less double beta decay of Formula omittedSe into the 0 Formula omitted, 2 Formula omitted and 2 Formula omitted excited states of Formula omittedKr with an exposure of 5.74 kg Formula omittedyr (2.24 Formula omitted10 Formula omitted emitters Formula omittedyr). We found no evidence of the decays and set the most stringent limits on the widths of these processes: Formula omitted( Formula omittedSe Formula omittedKr Formula omitted)8.55 Formula omitted10 Formula omitted yr Formula omitted, Formula omitted ( Formula omitted Se Formula omitted Kr Formula omitted) Formula omitted yr Formula omitted, Formula omitted( Formula omittedSe Formula omittedKr Formula omitted)8.25 Formula omitted10 Formula omitted yr Formula omitted (90 Formula omitted credible interval).
Localization and modeling of radioactive contaminations is a challenge that ultra-low background experiments are constantly facing. These are fundamental steps both to extract scientific results and ...to further reduce the background of the detectors. Here we present an innovative technique based on the analysis of
α
-
α
delayed coincidences in
232
Th and
238
U decay chains, developed to investigate the contaminations of the ZnSe crystals in the CUPID-0 experiment. This method allows to disentangle surface and bulk contaminations of the detectors relying on the different probability to tag delayed coincidences as function of the
α
decay position.
Abstract
In this work, achieved results on the NICHE project (Neutron Imaging in Cultural HEritage) are presented. It fits in the frame of the Cultural Heritage Network (CHNet) of the Italian Nuclear ...Physics Institute (INFN), and is devoted to the development and usage of a new neutron imaging station on the thermal port of the 250 kW TRIGA Mark-II reactor installed in the Laboratorio Energia Nucleare Applicata (LENA) in Pavia (Italy). The application of neutron radiography to the diagnostic in the cultural heritage field is quite widespread among the research community since it is a non-invasive technique which allows for revealing of the inner structure of the investigated objects, the identification of different materials and their relative spatial distribution with a suitable level of resolution and contrast. We present here the status and progresses within the project: technical characteristics of the beamline and the imaging station component, measuring configuration, possible applications, and examples.
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