71 research outputs found
Radioactive contamination of ZnWO4 crystal scintillators
The radioactive contamination of ZnWO4 crystal scintillators has been
measured deep underground at the Gran Sasso National Laboratory (LNGS) of the
INFN in Italy with a total exposure 3197 kg x h. Monte Carlo simulation,
time-amplitude and pulse-shape analyses of the data have been applied to
estimate the radioactive contamination of the ZnWO4 samples. One of the ZnWO4
crystals has also been tested by ultra-low background gamma spectrometry. The
radioactive contaminations of the ZnWO4 samples do not exceed 0.002 -- 0.8
mBq/kg (depending on the radionuclide), the total alpha activity is in the
range: 0.2 - 2 mBq/kg. Particular radioactivity, beta active 65Zn and alpha
active 180W, has been detected. The effect of the re-crystallization on the
radiopurity of the ZnWO4 crystal has been studied. The radioactive
contamination of samples of the ceramic details of the set-ups used in the
crystals growth has been checked by low background gamma spectrometry. A
project scheme on further improvement of the radiopurity level of the ZnWO4
crystal scintillators is briefly addressed.Comment: 15 pages, 8 figures, 6 tables, submitted for publicatio
NEVIS'22: A Stream of 100 Tasks Sampled from 30 Years of Computer Vision Research
We introduce the Never Ending VIsual-classification Stream (NEVIS'22), a
benchmark consisting of a stream of over 100 visual classification tasks,
sorted chronologically and extracted from papers sampled uniformly from
computer vision proceedings spanning the last three decades. The resulting
stream reflects what the research community thought was meaningful at any point
in time. Despite being limited to classification, the resulting stream has a
rich diversity of tasks from OCR, to texture analysis, crowd counting, scene
recognition, and so forth. The diversity is also reflected in the wide range of
dataset sizes, spanning over four orders of magnitude. Overall, NEVIS'22 poses
an unprecedented challenge for current sequential learning approaches due to
the scale and diversity of tasks, yet with a low entry barrier as it is limited
to a single modality and each task is a classical supervised learning problem.
Moreover, we provide a reference implementation including strong baselines and
a simple evaluation protocol to compare methods in terms of their trade-off
between accuracy and compute. We hope that NEVIS'22 can be useful to
researchers working on continual learning, meta-learning, AutoML and more
generally sequential learning, and help these communities join forces towards
more robust and efficient models that efficiently adapt to a never ending
stream of data. Implementations have been made available at
https://github.com/deepmind/dm_nevis
Game Plan: What AI can do for Football, and What Football can do for AI
The rapid progress in artificial intelligence (AI) and machine learning has opened unprecedented
analytics possibilities in various team and individual sports, including baseball, basketball, and
tennis. More recently, AI techniques have been applied to football, due to a huge increase in
data collection by professional teams, increased computational power, and advances in machine
learning, with the goal of better addressing new scientific challenges involved in the analysis of
both individual players’ and coordinated teams’ behaviors. The research challenges associated
with predictive and prescriptive football analytics require new developments and progress at the
intersection of statistical learning, game theory, and computer vision. In this paper, we provide
an overarching perspective highlighting how the combination of these fields, in particular, forms a
unique microcosm for AI research, while offering mutual benefits for professional teams, spectators,
and broadcasters in the years to come. We illustrate that this duality makes football analytics
a game changer of tremendous value, in terms of not only changing the game of football itself,
but also in terms of what this domain can mean for the field of AI. We review the state-of-theart and exemplify the types of analysis enabled by combining the aforementioned fields, including
illustrative examples of counterfactual analysis using predictive models, and the combination of
game-theoretic analysis of penalty kicks with statistical learning of player attributes. We conclude
by highlighting envisioned downstream impacts, including possibilities for extensions to other sports
(real and virtual)
Search for double beta decay processes in 106Cd with the help of 106CdWO4 crystal scintillator
A search for the double beta processes in 106Cd was carried out at the Gran
Sasso National Laboratories of the INFN (Italy) with the help of a 106CdWO4
crystal scintillator (215 g) enriched in 106Cd up to 66%. After 6590 h of data
taking, new improved half-life limits on the double beta processes in 106Cd
were established at the level of 10^{19}-10^{21} yr; in particular,
T_{1/2}(2\nu \epsilon \beta^+) > 2.1 10^{20} yr, T_{1/2}(2\nu 2\beta^+) > 4.3
10^{20} yr, and T_{1/2}(0\nu 2\epsilon) > 1.0 10^{21} yr. The resonant
neutrinoless double electron captures to the 2718 keV, 2741 keV and 2748 keV
excited states of 106Pd are restricted to T_{1/2}(0\nu 2K) > 4.3 10^{20} yr,
T_{1/2}(0\nu KL1) > 9.5 10^{20} yr and T_{1/2}(0\nu KL3) > 4.3 10^{20} yr,
respectively (all limits at 90% C.L.). A possible resonant enhancement of the
0\nu 2\epsilon processes is estimated in the framework of the QRPA approach.
The radioactive contamination of the 106CdWO4 crystal scintillator is reported.Comment: Minor changes of half-life limits after improving the data analysis;
version accepted for publication on Phys. Rev.
Low background detector with enriched 116CdWO4 crystal scintillators to search for double beta decay of 116Cd
A cadmium tungstate crystal boule enriched in Cd to 82% with mass of
1868 g was grown by the low-thermal-gradient Czochralski technique. The
isotopic composition of cadmium and the trace contamination of the crystal were
estimated by High Resolution Inductively Coupled Plasma Mass-Spectrometry. The
crystal scintillators produced from the boule were subjected to
characterization that included measurements of transmittance and energy
resolution. A low background scintillation detector with two CdWO
crystal scintillators (586 g and 589 g) was developed. The detector was running
over 1727 h deep underground at the Gran Sasso National Laboratories of the
INFN (Italy), which allowed to estimate the radioactive contamination of the
enriched crystal scintillators. The radiopurity of a third CdWO
sample (326 g) was tested with the help of ultra-low background high purity
germanium detector. Monte Carlo simulations of double
processes in Cd were used to estimate the sensitivity of an experiment
to search for double decay of Cd.Comment: 24 pages, 13 figures, 3 tables, accepted for publication on Journal
of Instrumentatio
Searches for neutrinoless resonant double electron captures at LNGS
Several experiments were performed during last years at underground (3600 m
w.e.) Laboratori Nazionali del Gran Sasso (LNGS) of the INFN (Italy) to search
for resonant 2 captures in 96Ru, 106Cd, 136Ce, 156Dy, 158Dy,
180W, 184Os, 190Pt with the help of HP Ge semiconductor detectors, and ZnWO4
and 106CdWO4 crystal scintillators. No evidence for r-2 decays
was found, and only T_{1/2} limits were established in the range of
10^{14}-10^{21} yr.Comment: Proceedings of TAUP 2011 Conferenc
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