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"Dafni, T."
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Search for Dark Matter Axions with CAST-CAPP
2022
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole magnet, has searched for axions in the 19.74
μ
eV to 22.47
μ
eV mass range. The detection concept follows the Sikivie haloscope principle, where Dark Matter axions convert into photons within a resonator immersed in a magnetic field. The CAST-CAPP resonator is an array of four individual rectangular cavities inserted in a strong dipole magnet, phase-matched to maximize the detection sensitivity. Here we report on the data acquired for 4124 h from 2019 to 2021. Each cavity is equipped with a fast frequency tuning mechanism of 10 MHz/ min between 4.774 GHz and 5.434 GHz. In the present work, we exclude axion-photon couplings for virialized galactic axions down to
g
a
γ
γ
= 8 × 10
−14
GeV
−1
at the 90% confidence level. The here implemented phase-matching technique also allows for future large-scale upgrades.
Haloscopes aim at detecting axions by converting them into photons using high-quality resonant cavities, where the cavity resonance should be tuned with the unknown axion mass. Here, the authors improve exclusion limits using four phase-matched resonant cavities and a fast frequency scanning technique.
Journal Article
First results of the CAST-RADES haloscope search for axions at 34.67 μeV
by
Widmann, E.
,
Golm, J.
,
Bräuninger, H.
in
Classical and Quantum Gravitation
,
Cosmology
,
Dark matter
2021
A
bstract
We present results of the Relic Axion Dark-Matter Exploratory Setup (RADES), a detector which is part of the CERN Axion Solar Telescope (CAST), searching for axion dark matter in the 34.67
μ
eV mass range. A radio frequency cavity consisting of 5 sub-cavities coupled by inductive irises took physics data inside the CAST dipole magnet for the first time using this filter-like haloscope geometry. An exclusion limit with a 95% credibility level on the axion-photon coupling constant of g
aγ
≳ 4 × 10
−
13
GeV
−
1
over a mass range of 34
.
6738
μ
eV
< m
a
<
34
.
6771
μ
eV is set. This constitutes a significant improvement over the current strongest limit set by CAST at this mass and is at the same time one of the most sensitive direct searches for an axion dark matter candidate above the mass of 25
μ
eV. The results also demonstrate the feasibility of exploring a wider mass range around the value probed by CAST-RADES in this work using similar coherent resonant cavities.
Journal Article
Background assessment for the TREX dark matter experiment
2019
TREX-DM is conceived to look for low-mass Weakly Interacting Massive Particles (WIMPs) using a gas Time Projection Chamber equipped with Micromegas readout planes at the Canfranc Underground Laboratory. The detector can hold in the active volume \\[\\sim 20~l\\] of pressurized gas up to 10 bar, corresponding to 0.30 kg of Ar or 0.16 kg of Ne. The Micromegas are read with a self-triggered acquisition, being thresholds below 0.4 keV (electron equivalent) at reach. A low background level in the lowest energy region is another essential requirement. To assess the expected background, all the relevant sources have been considered, including the measured fluxes of gamma radiation, muons and neutrons at the Canfranc Laboratory, together with the activity of most of the components used in the detector and ancillary systems, obtained in a complete assay program. The background contributions have been simulated by means of a dedicated application based on Geant4 and a custom-made code for the detector response. The background model developed for the detector presently installed in Canfranc points to levels from 1 to 10 counts \\[\\hbox {keV}^{-1}\\ \\hbox {kg}^{-1}\\ \\hbox {day}^{-1}\\] in the region of interest, making TREX-DM competitive in the search for low-mass WIMPs. A roadmap to further decrease it down to 0.1 counts \\[\\hbox {keV}^{-1}\\ \\hbox {kg}^{-1}\\ \\hbox {day}^{-1}\\] is underway.
Journal Article
TREX-DM: a low-background Micromegas-based TPC for low-mass WIMP detection
2016
If Dark Matter is made of Weakly Interacting Massive Particles (WIMPs) with masses below
∼
20
GeV, the corresponding nuclear recoils in mainstream WIMP experiments are of energies too close, or below, the experimental threshold. Gas Time Projection Chambers (TPCs) can be operated with a variety of target elements, offer good tracking capabilities and, on account of the amplification in gas, very low thresholds are achievable. Recent advances in electronics and in novel radiopure TPC readouts, especially micro-mesh gas structure (Micromegas), are improving the scalability and low-background prospects of gaseous TPCs. Here we present TREX-DM, a prototype to test the concept of a Micromegas-based TPC to search for low-mass WIMPs. The detector is designed to host an active mass of
∼
0.300
kg of Ar at 10 bar, or alternatively
∼
0.160
kg of Ne at 10 bar, with an energy threshold below 0.4 keVee, and is fully built with radiopure materials. We will describe the detector in detail, the results from the commissioning phase on surface, as well as a preliminary background model. The anticipated sensitivity of this technique may go beyond current experimental limits for WIMPs of masses of 2–8 GeV.
Journal Article
Nationwide Investigation of Respiratory Problemsin Sheep Lambs and Goat Kids in Greece
by
Fthenakis, George C.
,
Vaitsi, Georgia A.
,
Katsarou, Eleni I.
in
Agriculture
,
Air pollution
,
Analysis
2025
This study, carried out as part of a large countrywide investigation into the sheep and goat industries in Greece, focused on respiratory problems of lambs and kids in Greece. The work was performed as part of a wider study performed in farms throughout the country with the participation of farmers, by means of an in-person questionnaire investigation. The specific objectives of the study were (a) the assessment of the presence of respiratory problems in lambs and kids and (b) the identification of variables associated with the presence of these problems in the farms. Data were collected from 325 sheep flocks and 119 goat herds. The annual incidence rate for respiratory problems in lambs was 1.4% (95% confidence intervals: 1.3–1.4%) and that in kids was 1.1% (1.0–1.2%). The annual incidence rate was significantly lower in farms that applied a semi-extensive or extensive management system (1.2% in sheep and 1.0% in goat farms) than in farms that applied an intensive or semi-intensive or extensive (1.5% and 1.3%, respectively) management system. In multivariable analysis, the lack of a barn for lambs, the proximity (<10 km) of the farm to industrial sites, and the experience of farmers emerged as significant predictors in sheep farms, and the proximity to industrial sites and the administration of antibiotics to newborns routinely emerged as significant predictors in goat farms. Sheep (27.4%) and goat (22.7%) farmers considered ‘pneumonia’ as the second most important health problem of lambs and kids. Respiratory problems were more often declared an important problem by farmers in proximity to industrial sites: 21.6% versus 12.5%. Overall, the study contributes information regarding the presence of respiratory problems in lambs and kids in Greece. A notable finding has been the association of proximity to industrial sites with a higher incidence rate of respiratory problems of lambs and kids in the farms. This has similarities to the results of relevant studies on people and potentially reflects that air pollution in the farm environment might be a factor to take into account in health management. One may also postulate that, possibly, data from farms can be employed to indicate potential risk from air pollution for humans, although further and more detailed work will be necessary to draw relevant conclusions.
Journal Article
A Note on Some Health-Related Outcomes in Small Ruminant Farms with Common Grazing with Wildlife Ruminants
by
Lianou, Dafni T
,
Michael, Charalambia K
,
Katsarou, Eleni I
in
abortion
,
Agriculture
,
Communication
2025
The specific objective of the current paper was the description of some health-related outcomes in sheep and goat farms in Greece with common grazing with wildlife ruminants. Faecal samples were collected and information regarding health management applied on farms was obtained from sheep and goat farms located throughout Greece (325 and 119 farms, respectively). Common grazing of livestock (sheep, goats) with wildlife ruminants (roe deer, red deer) was reported in 9.2% of farms. Faecal epg counts in farms with common grazing with wildlife ruminants were higher than in farms with no common grazing: respective median values were 270 epg versus 150 epg; also, there was a tendency for faecal counts >300 epg to be recorded more frequently among the former farms (36.1% versus 23.1% of farms). Median annual incidence of cases of abortion and of cases of diarrhoea in lambs/kids was significantly higher in farms with common grazing with wildlife ruminants: 1.7% and 9.0%, respectively, versus 0.0% and 1.7%, respectively, in farms with no common grazing. The findings have revealed associations of common grazing with wildlife ruminants with the health of sheep and goats. These can have implications in the health management of farms, for example, in the administration of anthelmintic treatments and in the development of vaccination programmes in livestock farms.
Journal Article
Micromegas planes for the neutrinoless double beta decay search with NEXT
2011
NEXT is a project to look for the neutrinoless double beta decay of 136Xe in the Canfranc Underground Laboratory (LSC) in the Spanish Pyrenees. The goal of the project is to construct NEXT-100, which will hold 100kg of pressurized Xe gas, planned to run in late 2013. The project is currently progressing through its R&D phase: the first big (1 kg) prototypes will be taking data during 2011, exploring different options for the readout. One of them is reading the charge with the help of microbulk Micromegas planes. This option is discussed here.
Journal Article
Clinical Characterization of Pediatric Erythromelalgia: A Single-Center Case Series
by
Halpin, Meghan
,
Brownstein, Catherine A.
,
Berde, Charles B.
in
Analgesics
,
Arthritis
,
Case reports
2023
Erythromelalgia is a descriptive term for severe burning pain and erythema in the distal extremities relieved by cold and exacerbated by heat. Pediatric case series to date are relatively small. We extracted and analyzed medical record data for 42 pediatric patients to describe clinical characteristics, associated conditions, and responses to treatments. Informed consent was obtained according to an IRB-approved protocol that included gene discovery. Three patients had confirmed Nav1.7 sodium channelopathies, with six additional patients under investigation with novel gene candidates. There was a female predominance (2.5:1), and the median onset age was 12 years (IQR = 3–14). Patients saw a median of three specialists (IQR = 2–3) for a diagnosis. The majority (90%) reported bilateral symptoms. Cooling methods usually provided partial relief, while heat and exercise exacerbated pain. No medication appeared to be consistently effective; commonly prescribed medications included sodium channel blockers (n = 37), topical analgesics (n = 26), gabapentin (n = 22), and aspirin (n = 15). Based on the currently published literature, we believe this cohort is the largest pediatric study of erythromelalgia to date. Many findings are consistent with those of previously published case series. Work is in progress to establish a prospective cohort and multi-center registry.
Journal Article
The TREX-DM experiment at the Canfranc Underground Laboratory
2020
TREX-DM (TPC Rare Event eXperiment for Dark Matter) is intended to look for low mass WIMPs in the Canfranc Underground Laboratory (LSC) in Spain, using light elements (Ne, Ar) as target in a high pressure TPC equipped with Micromegas readouts. Here, a description of the detector, the first results from commissioning data and the expected sensitivity from the developed background model are briefly presented.
Journal Article
Present Status and Future Perspectives of the NEXT Experiment
2014
NEXT is an experiment dedicated to neutrinoless double beta decay searches in xenon. The detector is a TPC, holding 100 kg of high-pressure xenon enriched in the 136Xe isotope. It is under construction in the Laboratorio Subterráneo de Canfranc in Spain, and it will begin operations in 2015. The NEXT detector concept provides an energy resolutionbetter than 1% FWHM and a topological signal that can be used to reduce the background. Furthermore, the NEXT technology can be extrapolated to a 1 ton-scale experiment.
Journal Article