308 research outputs found
An innovative technique for the investigation of the 4-fold forbidden beta-decay of V
For the first time a Vanadium-based crystal was operated as cryogenic
particle detector. The scintillating low temperature calorimetric technique was
used for the characterization of a 22 g YVO crystal aiming at the
investigation of the 4-fold forbidden non-unique decay of V.
The excellent bolometric performance of the compound together with high light
output of the crystal makes it an outstanding technique for the study of such
elusive rate process. The internal radioactive contaminations of the crystal
are also investigated showing that an improvement on the current status of
material selection and purification are needed, U and Th
are measured at the level of 28 mBq/kg, 1.3 Bq/kg and 28 mBq/kg, respectively.
In this work, we also discuss a future upgrade of the experimental set-up which
may pave the road for the detection of the rare V decay
First array of enriched ZnSe bolometers to search for double beta decay
The R&D activity performed during the last years proved the potential of ZnSe
scintillating bolometers to the search for neutrino-less double beta decay,
motivating the realization of the first large-mass experiment based on this
technology: CUPID-0. The isotopic enrichment in Se, the ZnSe
crystals growth, as well as the light detectors production have been
accomplished, and the experiment is now in construction at Laboratori Nazionali
del Gran Sasso (Italy). In this paper we present the results obtained testing
the first three ZnSe crystals operated as scintillating bolometers, and
we prove that their performance in terms of energy resolution, background
rejection capability and intrinsic radio-purity complies with the requirements
of CUPID-0
Inflammation and erythropoiesis-stimulating agent response in hemodialysis patients : a self-matched longitudinal study of anemia management in the Dialysis Outcomes and Practice Patterns Study (DOPPS)
Rationale & objective: Previous studies of inflammation and anemia management in hemodialysis (HD) patients may be biased due to patient differences. We used a self-matched longitudinal design to test whether new inflammation, defined as an acute increase in C-reactive protein (CRP) level, reduces hemoglobin response to erythropoiesis-stimulating agent (ESA) treatment.
Study design: Self-matched longitudinal design.
Setting & participants: 3,568 new inflammation events, defined as CRP level > 10 mg/L following a 3-month period with CRP level ≤ 5 mg/L, were identified from 12,389 HD patients in the Dialysis Outcomes and Practice Patterns Study (DOPPS) phases 4 to 6 (2009-2018) in 10 countries in which CRP is routinely measured.
Predictor: "After" (vs "before") observing a high CRP level.
Outcomes: Within-patient changes in hemoglobin level, ESA dose, and ESA hyporesponsiveness (hemoglobin 6,000 [Japan] or >8,000 [Europe] U/wk).
Analytical approach: Linear mixed models and modified Poisson regression.
Results: Comparing before with after periods, mean hemoglobin level decreased from 11.2 to 10.9 g/dL (adjusted mean change, -0.26 g/dL), while mean ESA dose increased from 6,320 to 6,960 U/wk (adjusted relative change, 8.4%). The prevalence of ESA hyporesponsiveness increased from 7.6% to 12.3%. Both the unadjusted and adjusted prevalence ratios of ESA hyporesponsiveness were 1.68 (95% CI, 1.48-1.91). These associations were consistent in sensitivity analyses varying CRP thresholds and were stronger when the CRP level increase was sustained over the 3-month after period.
Limitations: Residual confounding by unmeasured time-varying risk factors for ESA hyporesponsiveness.
Conclusions: In the 3 months after HD patients experienced an increase in CRP levels, hemoglobin levels declined quickly, ESA doses increased, and the prevalence of ESA hyporesponsiveness increased appreciably. Routine CRP measurement could identify inflammation as a cause of worsened anemia. In turn, these findings speak to a potentially important role for anemia therapies that are less susceptible to the effects of inflammation
COSINUS: Cryogenic Calorimeters for the Direct Dark Matter Search with NaI Crystals
COSINUS (Cryogenic Observatory for SIgnatures seen in Next-generation Underground Searches) is an experiment employing cryogenic calorimeters, dedicated to direct dark matter search in underground laboratories. Its goal is to cross-check the annual modulation signal the DAMA collaboration has been detecting for about 20 years (Bernabei et al. in Nucl Part Phys Proc 303-305:74-79, 2018. 10.1016/j.nuclphysbps.2019.03.015) and which has been ruled out by other experiments in certain dark matter scenarios. COSINUS can provide a model-independent test by the use of the same target material (NaI), with the additional chance of discriminating beta/gamma events from nuclear recoils on an event-by-event basis, by the application of a well-established temperature sensor technology developed within the CRESST collaboration. Each module is constituted by two detectors: the light detector, that is a silicon beaker equipped with a transition edge sensor (TES), and the phonon detector, a small cubic NaI crystal interfaced with a carrier of a harder material (e.g. CdWO4), also instrumented with a TES. This technology had so far never been applied to NaI crystals because of several well-known obstacles, and COSINUS is the first experiment which succeeded in operating NaI crystals as cryogenic calorimeters. Here, we present the COSINUS project, describe the achievements and the challenges of the COSINUS prototype development and discuss the status and the perspectives of this NaI-based cryogenic frontier
Возможность использования высокочастотного CuBr-лазера для создания скоростного лазерного монитора
Представлены оценки максимальных температур источников как внешней, так и собственной засветки, при которых будут иметь место искажения изображений, формируемых посредствам активных оптических систем. Показана возможность использования высокочастотного CuBr-лазера в качестве усилителя яркости лазерного монитора
Deep-underground dark matter search with a COSINUS detector prototype
Sodium iodide (NaI) based cryogenic scintillating calorimeters using quantum
sensors for signal read out have shown promising first results towards a
model-independent test of the annually modulating signal detected by the
DAMA/LIBRA dark matter experiment. The COSINUS collaboration has previously
reported on the first above-ground measurements using a dual channel readout of
phonons and light based on transition edge sensors (TESs) that allows for
particle discrimination on an event-by-event basis. In this letter, we outline
the first underground measurement of a NaI cryogenic calorimeter read out via
the novel remoTES scheme. A 3.67 g NaI absorber with an improved silicon light
detector design was operated at the Laboratori Nazionali del Gran Sasso, Italy.
A significant improvement in the discrimination power of /-events
to nuclear recoils was observed with a five-fold improvement in the nuclear
recoil baseline resolution, achieving = 441 eV. Furthermore, we
present a limit on the spin-independent dark-matter nucleon elastic scattering
cross-section achieving a sensitivity of (pb) with an exposure of
only 11.6 g d.Comment: 11 pages, 14 figure
- …