30 research outputs found
Ultra low background Micromegas detectors for BabyIAXO solar axion search
The International AXion Observatory (IAXO) is a large scale axion helioscope
that will look for axions and axion-like particles produced in the Sun with
unprecedented sensitivity. BabyIAXO is an intermediate experimental stage that
will be hosted at DESY (Germany) and that will test all IAXO subsystems serving
as a prototype for IAXO but at the same time as a fully-fledged helioscope with
potential for discovery.
One of the crucial components of the project is the ultra-low background
X-ray detectors that will image the X-ray photons produced by axion conversion
in the experiment. The baseline detection technology for this purpose are
Micromegas (Microbulk) detectors. We will show the quest and the strategy to
attain the very challenging levels of background targeted for BabyIAXO that
need a multi-approach strategy coming from ground measurements, screening
campaigns of components of the detector, underground measurements, background
models, in-situ background measurements as well as powerful rejection
algorithms. First results from the commissioning of the BabyIAXO prototype will
be shown.Comment: 4 pages, 2 figures, submitted for the proceedings of the
International Conference on Micro Pattern Gaseous Detectors, December 2022,
Israe
Search for Dark Matter Axions with CAST-CAPP
The CAST-CAPP axion haloscope, operating at CERN inside the CAST dipole
magnet, has searched for axions in the 19.74 eV to 22.47 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
at the 90% confidence
level. The here implemented phase-matching technique also allows for future
large-scale upgrades.Comment: 24 pages, 5 figures, Published version available with Open Access at
https://www.nature.com/articles/s41467-022-33913-
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Shaping the future of probiotics and prebiotics
Recent and ongoing developments in microbiome science are enabling new frontiers of research for probiotics and prebiotics. Novel types, mechanisms, and applications currently under study have the potential to change scientific understanding as well as nutritional and healthcare applications of these interventions. The expansion of related fields of microbiome-targeted interventions, and an evolving landscape for implementation across regulatory, policy, prescriber, and consumer spheres, portends an era of significant change. In this review we examine recent, emerging, and anticipated trends in probiotic and prebiotic science, and create a vision for broad areas of developing influence in the field
Towards a macroscope: Leveraging technology to transform the breadth, scale and resolution of macroecological data
Static species distribution models in the marine realm: The case of baleen whales in the Southern Ocean
Aim
Information on the spatio-temporal distribution of marine species is essential for developing proactive management strategies. However, sufficient information is seldom available at large spatial scales, particularly in polar areas. The Southern Ocean (SO) represents a critical habitat for various species, particularly migratory baleen whales. Still, the SO’s remoteness and sea ice coverage disallow obtaining sufficient information on baleen whale distribution and niche preference. Here, we used presence-only species distribution models to predict the circumantarctic habitat suitability of baleen whales and identify important predictors affecting their distribution.
Location
The Southern Ocean (SO).
Methods
We used Maxent to model habitat suitability for Antarctic minke, Antarctic blue, fin and humpback whales. Our models employ extensive circumantarctic data and carefully prepared predictors describing the SO’s environment and two spatial sampling bias correction options. Species-specific spatial-block cross-validation was used to optimize model complexity and for spatially independent model evaluation.
Results
Model performance was high on cross-validation, with generally little predicted uncertainty. The most important predictors were derived from sea ice, particularly seasonal mean and variability of sea ice concentration and distance to the sea ice edge.
Main conclusions
Our models support the usefulness of presence-only models as a cost-effective tool in the marine realm, particularly for studying the migratory whales’ distribution. However, we found discrepancies between our results and (within) results of similar studies, mainly due to using different species data quality and quantity, different study area extent and methodological reasons. We further highlight the limitations of implementing static distribution models in the highly dynamic marine realm. Dynamic models, which relate species information to environmental conditions contemporaneous to species occurrences, can predict near-real-time habitat suitability, necessary for dynamic management. Nevertheless, obtaining sufficient species and environmental predictors at high spatio-temporal resolution, necessary for dynamic models, can be challenging from polar regions
Using Micromegas detectors for direct dark matter searches: challenges and perspectives
International audienceGas time projection chambers (TPCs) with Micromegas pixelated readouts are being used in dark matter searches and other rare event searches, due to their potential in terms of low background levels, energy and spatial resolution, gain, and operational stability. Moreover, these detectors can provide precious features,such as topological information, allowing for event directionality and powerful signal-background discrimination. The Micromegas technology of the microbulk type is particularly suited to low-background applications and is being exploited by detectors for CAST and IAXO (solar axions) and TREX-DM (low-mass WIMPs) experiments. Challenges for the future include reducing intrinsic background levels, reaching lower energy detection levels, and technical issues such as robustness of detector, new design choices, novel gas mixtures and operation points, scaling up to larger detector sizes, handling large readout granularity, etc. We report on the status and prospects of the development ongoing in the context of IAXO and TREX-DM experiments, pointing to promising perspectives for the use of Micromegas detectors in directdark matter searche
Background discrimination with a Micromegas detector prototype and veto system for BabyIAXO
International audienceIn this paper we present measurements performed with a Micromegas X-ray detector setup. The detector is a prototype in the context of the BabyIAXO helioscope, which is under construction to search for an emission of the hypothetical axion particle from the sun. An important component of such a helioscope is a low background X-ray detector with a high efficiency in the 1-10 keV energy range. The goal of the measurement was to study techniques for background discrimination. In addition to common techniques we used a multi-layer veto system designed to tag cosmogenic neutron background. Over an effective time of 52 days, a background level of was reached in a laboratory at above ground level. This is the lowest background level achieved at surface level. In this paper we present the experimental setup, show simulations of the neutron-induced background, and demonstrate the process to identify background signals in the data. Finally, prospects to reach lower background levels down to will be discussed
X-ray detectors for the BabyIAXO solar axion search
International audienceBabyIAXO is a helioscope under construction to search for an emission of the axion particle from the Sun. At the same time it serves as an intermediate stage towards the International Axion Observatory (IAXO). An integral component of this experiment is a low background X-ray detector with a high efficiency in the 1–10 keV energy range. Micromegas detectors are considered as baseline technology for BabyIAXO thanks to the relatively high efficiency and very low background level. Other detector technologies developed to reach better energy resolution while maintaining high efficiency and low background level are also under study. In this paper, we review the BabyIAXO design and present the analysis of data taken with the prototype of an IAXO Micromegas detector. A background level of 8.8×10−7counts keV−1cm−2s−1 was reached
X-ray detectors for the BabyIAXO solar axion search
BabyIAXO is a helioscope under construction to search for an emission of the axion particle from the Sun. At the same time it serves as an intermediate stage towards the International Axion Observatory (IAXO). An integral component of this experiment is a low background X-ray detector with a high efficiency in the 1–10 keV energy range. Micromegas detectors are considered as baseline technology for BabyIAXO thanks to the relatively high efficiency and very low background level. Other detector technologies developed to reach better energy resolution while maintaining high efficiency and low background level are also under study. Inthis paper, we review the BabyIAXO design and present the analysis of data taken with he prototype of an IAXO Micromegas detector. A background level of 8.8 × 10−7 counts keV−1 cm−2 s−1 was reached
Bicycle-sharing systems in an alternative/diverse economy perspective: a sympathetic critique
This contribution puts bicycle-sharing systems (BSSs) as a rather recent, environmentally friendly form of urban mobility in the context of broader societal changes. More specifically, we discuss to what extent BSS and their various modes of organisation can be regarded as an “alternative” consumption practice, explicitly designed to deliver more social just outcomes, taking the diverse economy framework of Gibson-Graham as a key tool of analysis. Our examination unfolds a range of limitations of BSSs for (strong) sustainable development, but also a number of obvious and less obvious prospects and opportunities