Sensitivities of current directional dark matter search detectors using gas time projection chambers are now constrained by target mass. A ton-scale gas TPC detector will require large charge readout ...areas. We present a first demonstration of a novel ThGEM-Multiwire hybrid charge readout technology which combines the robust nature and high gas gain of Thick Gaseous Electron Multipliers with lower capacitive noise of a one-plane multiwire charge readout in SF6 target gas. Measurements performed with this hybrid detector show an ion drift velocity of 138±10 ms−1 in a reduced drift field E/N of 93 ×10−17 Vcm2 with an effective gas gain of 2470±160 in 20 Torr of pure SF6 target gas.
The CYGNO project aims to study rare events, as low-mass (few GeV) Dark Matter (DM) particle or solar neutrino interactions, exploiting the approach of the optical readout of the scintillation light ...produced in the amplification in a multiple Gas Electron Multiplier (GEM) structure, of the primary ionization originated in large volume Time Projection Chamber (TPCs).
The volume is filled with an He:CF4 gas mixture at atmospheric pressure. The 3D topology, and therefore direction of the recoils, is reconstructed thanks to the combined use of high-granularity, high sensitivity sCMOS cameras, for the precise tracking of the projection of the recoils on the GEM plane, and of fast light sensors in order to obtain the coordinate perpendicular to the camera plane.
To conclude the R&D phase, the 50 L prototype, called Long Imaging ModulE (LIME), was moved underground at the Laboratori Nazionali del Gran Sasso (LNGS) in order to study the performance of the CYGNO experimental approach in a low background environment and to assess the contributions to the background from different sources, also comparing with Monte Carlo simulations.
Stability studies and the effects of environmental condition on the light yield will be discussed, focusing on the effect of humidity on the detector response and stability amount and rate of self-sustaining micro-discharges. This is a crucial step towards the development of a large demonstrator.
•A TPC filled with a gas mixture based on light atoms as target.•The combined usage of PMTs and sCMOS camera enables the 3D tracks reconstruction.•Studies on the effects of environmental condition on the light yield.
50 litres TPC with sCMOS-based optical readout for the CYGNO project Mazzitelli, G.; Domingues, F. Amaro; Baracchini, E. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
01/2023, Letnik:
1045
Journal Article
Recenzirano
The CYGNO project aims at realizing a one cubic meter gaseous Time Projection Chamber (TPC) equipped with Scientific CMOS (sCMOS) commercial cameras to optically readout Gas Electron Multiplier (GEM) ...to be operated at the underground of Gran Sasso National Laboratory (LNGS).
The purpose of the project is to study the technology needed for a large size gaseous TPC (30–100 m3) operated at atmospheric pressure for the directional search of low mass O(GeV) dark matter and low energy (eg solar) neutrinos astronomy. The roadmap of the project foresees the underground operation of a 50 litres TPC prototype, called LIME, the largest TPC realized with this technology, fully equipped with copper and water shielding. LIME is equivalent to about a 1/20 of the CYGNO demonstrator and aims to validate: The construction materials, the Monte Carlo simulations, the data reconstruction and the particle identification performances at low energy threshold. LIME is under installation at the LNGS and it is supposed to start data taking at the beginning of 2022. The detector description and installation will be presented, as well as the overground performance and limitations that require underground characterization.
Snoring is extremely common in the general population and may indicate OSA. However, snoring is not objectively measured during polysomnography, and no standard treatment is available for primary ...snoring or when snoring is associated with mild forms of OSA. This study determined the effects of oropharyngeal exercises on snoring in minimally symptomatic patients with a primary complaint of snoring and diagnosis of primary snoring or mild to moderate OSA.
Patients were randomized for 3 months of treatment with nasal dilator strips plus respiratory exercises (control) or daily oropharyngeal exercises (therapy). Patients were evaluated at study entry and end by sleep questionnaires (Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index) and full polysomnography with objective measurements of snoring.
We studied 39 patients (age, 46 ± 13 years; BMI, 28.2 ± 3.1 kg/m2; apnea-hypopnea index (AHI), 15.3 ± 9.3 events/h; Epworth Sleepiness Scale, 9.2 ± 4.9; Pittsburgh Sleep Quality Index, 6.4 ± 3.3). Control (n = 20) and therapy (n = 19) groups were similar at study entry. One patient from each group dropped out. Intention-to-treat analysis was used. No significant changes occurred in the control group. In contrast, patients randomized to therapy experienced a significant decrease in the snore index (snores > 36 dB/h), 99.5 (49.6-221.3) vs 48.2 (25.5-219.2); P = .017 and total snore index (total power of snore/h), 60.4 (21.8-220.6) vs 31.0 (10.1-146.5); P = .033.
Oropharyngeal exercises are effective in reducing objectively measured snoring and are a possible treatment of a large population suffering from snoring.
ClinicalTrials.gov; No.: NCT01636856; URL: www.clinicaltrials.gov.
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