325 research outputs found
Final results of an experiment to search for 2beta processes in zinc and tungsten with the help of radiopure ZnWO4 crystal scintillators
A search for the double beta decay of zinc and tungsten isotopes has been
performed with the help of radiopure ZnWO4 crystal scintillators (0.1-0.7 kg)
at the Gran Sasso National Laboratories of the INFN. The total exposure of the
low background measurements is 0.529 kg yr. New improved half-life limits on
the double beta decay modes of 64Zn, 70Zn, 180W, and 186W have been established
at the level of 10^{18}-10^{21} yr. In particular, limits on double electron
capture and electron capture with positron emission in 64Zn have been set:
T_{1/2}(2\nu 2K) > 1.1 10^{19} yr, T_{1/2} (0\nu 2\epsilon) > 3.2 10^{20} yr,
T_{1/2} (2\nu \epsilon \beta^+) > 9.4 10^{20} yr, and T_{1/2} (0\nu \epsilon
\beta^+) > 8.5 10^{20} yr, all at 90% C.L. Resonant neutrinoless double
electron capture in 180W has been restricted on the level of T_{1/2} (0\nu
2\epsilon) > 1.3 10^{18} yr. A new half-life limit on alpha transition of 183W
to the metastable excited level 1/2^- 375 keV of 179Hf has been established:
T_{1/2} > 6.7 10^{20} yr.Comment: This is an author-created, un-copyedited version of an article
published in J. Phys. G: Nucl. Part. Phys. IOP Publishing Ltd is not
responsible for any errors or omissions in this version of the manuscript or
any version derived from it. The definitive publisher authenticated version
is available online at doi: 10.1088/0954-3899/38/11/11510
Investigation of rare nuclear decays with BaF crystal scintillator contaminated by radium
The radioactive contamination of a BaF scintillation crystal with mass of
1.714 kg was measured over 101 hours in the low-background DAMA/R&D set-up deep
underground (3600 m w.e.) at the Gran Sasso National Laboratories of INFN
(LNGS, Italy). The half-life of Po (present in the crystal scintillator
due to contamination by radium) was measured as Po) =
298.80.8(stat.)1.4(syst.) ns by analysis of the events' pulse
profiles. The Rn nuclide is known as 100% decaying via emission of
particle with = 3.82 d; however, its decay is also
energetically allowed with keV. Search for decay chains of
events with specific pulse shapes characteristic for or for
signals and with known energies and time differences allowed us
to set, for the first time, the limit on the branching ratio of Rn
relatively to decay as % at 90% C.L. (equivalent to
limit on partial half-life y). Half-life limits of
Pb, Rn and Ra relatively to decays are also
improved in comparison with the earlier results.Comment: 10 pages, 9 figures, 2 table
Search for long-lived superheavy eka-tungsten with radiopure ZnWO crystal scintillator
The data collected with a radioactively pure ZnWO crystal scintillator
(699 g) in low background measurements during 2130 h at the underground (3600 m
w.e.) Laboratori Nazionali del Gran Sasso (INFN, Italy) were used to set a
limit on possible concentration of superheavy eka-W (seaborgium Sg, Z = 106) in
the crystal. Assuming that one of the daughters in a chain of decays of the
initial Sg nucleus decays with emission of high energy particle
( MeV) and analyzing the high energy part of the measured
spectrum, the limit N(Sg)/N(W) < 5.5 10 atoms/atom at
90% C.L. was obtained (for Sg half-life of 10 yr). In addition, a limit on
the concentration of eka-Bi was set by analysing the data collected with a
large BGO scintillation bolometer in an experiment performed by another group
[L. Cardani et al., JINST 7 (2012) P10022]: N(eka-Bi)/N(Bi) < 1.1
10 atoms/atom with 90% C.L. Both the limits are comparable with those
obtained in recent experiments which instead look for spontaneous fission of
superheavy elements or use the accelerator mass spectrometry.Comment: 9 pages, 2 figures; in press on Physica Script
New limits on , and decay of Ce and Ce with deeply purified cerium sample
A search for double electron capture (), electron capture with
positron emission (), and double positron emission
) in Ce and Ce was realized with a 465 cm
ultra-low background HP Ge spectrometer over 2299 h at the Gran Sasso
underground laboratory. A 627 g sample of cerium oxide deeply purified by
liquid-liquid extraction method was used as a source of quanta
expected in double decay of the cerium isotopes. New improved half-life
limits were set on different modes and channels of double decay of
Ce and Ce at the level of yr.Comment: 19 pages, 6 figures, 2 table
Search for double beta decay of Ce and Ce with HPGe gamma detector
Search for double decay of Ce and Ce was realized
with 732 g of deeply purified cerium oxide sample measured over 1900 h with the
help of an ultra-low background HPGe detector with a volume of 465
cm at the STELLA facility of the Gran Sasso National Laboratories of the
INFN (Italy). New improved half-life limits on double beta processes in the
cerium isotopes were set at the level of ~yr;
many of them are even two orders of magnitude larger than the best previous
results.Comment: 21 pages, 6 figures, 3 tables; version accepted for publication on
Nucl. Phys.
Improvement of radiopurity level of enriched CdWO and ZnWO crystal scintillators by recrystallization
As low as possible radioactive contamination of a detector plays a crucial
role to improve sensitivity of a double beta decay experiment. The radioactive
contamination of a sample of CdWO crystal scintillator by thorium
was reduced by a factor , down to the level 0.01 mBq/kg
(Th), by exploiting the recrystallization procedure. The total alpha
activity of uranium and thorium daughters was reduced by a factor ,
down to 1.6 mBq/kg. No change in the specific activity (the total
activity and Th) was observed in a sample of ZnWO crystal produced
by recrystallization after removing mm surface layer of the
crystal.Comment: 14 pages, 5 figures and 2 table
First search for double-beta decay of 184Os and 192Os
A search for double-beta decay of osmium has been realized for the first time
with the help of an ultra-low background HPGe gamma detector at the underground
Gran Sasso National Laboratories of the INFN (Italy). After 2741 h of data
taking with a 173 g ultra-pure osmium sample limits on double-beta processes in
184Os have been established at the level of T_{1/2} about 10^{14}-10^{17} yr.
Possible resonant double-electron captures in 184Os were searched for with a
sensitivity T_{1/2} about 10^{16} yr. A half-life limit T_{1/2} > 5.3 10^{19}
yr was set for the double-beta decay of 192Os to the first excited level of
192Pt. The radiopurity of the osmium sample has been investigated and
radionuclides 137Cs, 185Os and 207Bi were detected in the sample, while
activities of 40K, 60Co, 226Ra and 232Th were limited at the mBq/kg level.Comment: 12 pages, 7 figures, 2 table
Search for 2\beta\ decays of 96Ru and 104Ru by ultra-low background HPGe gamma spectrometry at LNGS: final results
An experiment to search for double beta decay processes in 96Ru and 104Ru,
which are accompanied by gamma rays, has been realized in the underground Gran
Sasso National Laboratories of the I.N.F.N. (Italy). Ruthenium samples with
masses of about (0.5-0.7) kg were measured with the help of ultra-low
background high purity Ge gamma ray spectrometry. After 2162 h of data taking
the samples were deeply purified to reduce the internal contamination of 40K.
The last part of the data has been accumulated over 5479 h. New improved half
life limits on 2\beta+/\epsilon \beta+/2\epsilon\ processes in 96Ru have been
established on the level of 10^{20} yr, in particular for decays to the ground
state of 96Mo: T1/2(2\nu 2\beta+) > 1.4 10^{20} yr, T1/2(2\nu \epsilon\beta+) >
8.0 10^{19} yr and T1/2(0\nu 2K) > 1.0 10^{21} yr (all limits are at 90% C.L.).
The resonant neutrinoless double electron captures to the 2700.2 keV and 2712.7
keV excited states of 96Mo are restricted as: T1/2(0\nu KL) > 2.0 10^{20} yr
and T1/2(0\nu 2L) > 3.6 10^{20} yr, respectively. Various two neutrino and
neutrinoless 2\beta\ half lives of 96Ru have been estimated in the framework of
the QRPA approach. In addition, the T1/2 limit for 0\nu 2\beta- transitions of
104Ru to the first excited state of 104Pd has been set as > 6.5 10^{20} yr.Comment: 14 pages, 5 figures, 2 tables; version accepted for publication on
Phys. Rev.
Using HoloLens Mixed Reality to research correlations between language and movement: a case study
Communication can be defined as the understanding and exchanging of meaningful messages. The role of communication is central to the lives of human beings as, everyday, we use language to interact with the world around us. Linguistic skills play a fundamental role in this scenario and Language Disorders (LD) are impairments that limit the processing of linguistic information. Early and accurate identification of LD is thus essential to promote lifelong learning and well-being. From an evolutionary perspective, some human language constructs evolved from an ancestral motor system and share the same neural pathways in the Broca’s area of the brain. This suggests a correlation between action and language. If such a relationship is well established and reliable, it would be possible to use the former as a marker of the latter. The hypothesis of our work, in a nutshell, is that movement can be a predictor of language. To study this correlation, we developed C(H)o(L)ordination, a Mixed Reality (MR) application for HoloLens 2. The application offers several activities based on visual stimuli involving motor movements, which tap on the same skills needed to perform some language tasks. We performed an exploratory study with N=22 users to test the application usability and user experience. The results suggest that C(H)o(L)ordination is a usable and powerful tool to gather insights on the ongoing debate about language evolution and language disorders
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