With the upgraded beam luminosity in LHC Run 3, the detector technology for the innermost end-cap muon station (small wheel) of the ATLAS detector needs to be upgraded. The new technology should be ...able to meet the demands of spatial resolution, high efficiency as well as fast response of the present system at the expected higher background rate, up to 20 kHz/cm
2
. The detectors which perform precision tracking and triggering in the New Small Wheel (NSW) are Micromegas (MM) and small-strip Thin Gas Chamber (sTGC) respectively. The detectors are also complementary to each other. The Micromegas quadruplets are delivered to CERN from the different construction sites. Two Micromegas quadruplets are integrated to build a double wedge. After the electronic integration, the double wedges are tested with cosmic muons at the cosmic stand at CERN. The final high voltage configuration is verified and various parameters like the efficiency, cluster size, strip multiplicity per readout layer are measured. The double wedge of the Micromegas sector is qualified for the final integration with the sTGC wedges before mounting on the NSW. The procedure and the cosmic test results of the final validation of Micromegas double wedges is presented.
Abstract
The experimental requirements in current and near-future accelerators and experiments have stimulated intense interest in R&D of detectors with high precision timing capabilities, resulting ...in novel instrumentation. During the R&D phase, the timing information is usually extracted from the signal using the full waveform collected with fast oscilloscopes; this method produces a large amount of data and it becomes impractical when the detector has many channels. Towards practical applications, the data acquisition should be undertaken by dedicated front-end electronic units. The selected technology should retain the signal timing characteristics and consequently the timing resolution on the particle’s arrival time. We investigate the adequacy of the Leading-edge discrimination timing technique to achieve timing with a precision in the order of tens of picosecond with novel gaseous detectors. The method under investigation introduces a “time-walk” which impinges on the timing resolution. We mitigate the effect of time-walk using three different approaches; the first based on multiple Time-over-Threshold, the second based on multiple Charge-over-Threshold information and the third uses artificial Neural Network techniques. The results of this study prove the feasibility of the methods and their ability to achieve a timing resolution comparable to that obtained using the full waveforms.
The dimorphic fungus
is the causal agent of peach leaf curl disease, which affects leaves, flowers, and fruits. An RNA-seq approach was employed to gain insights into the transcriptional ...reprogramming of a peach cultivar during leaf inoculation with the yeast phase of the fungus across a compatible interaction. The results uncovered modulations of specific peach differentially expressed genes (DEGs) in peaches and pathways related to either the induction of host defense responses or pathogen colonization and disease spread. Expression profiles of DEGs were shown to be highly time-dependent and related to the presence of the two forms of the fungal growth, the inoculated yeast form and the later biotrophic phase during mycelial development. In parallel, this differential reprogramming was consistent with a diphasic detection of fungal load in the challenged leaves over the 120 h after inoculation (HAI) period. Leaf defense responses either occurred during the early yeast phase inoculation at 24 HAI, mediated primarily by cell wall modification processes, or more pronouncedly during the biotrophic phase at 72 HAI, as revealed by the activation of DEGs related to pathogen perception, signaling transduction, and secondary metabolism towards restraining further hypha proliferation. On the contrary, the expression patterns of specific DEGs at 120 HAI might further contribute to host susceptibility. These findings will further allow us to elucidate the molecular responses beyond the peach-
interaction.
We investigate the impact of wind and solar power generation on the level and volatility of wholesale electricity prices in the Greek electricity market from August 2012 to December 2018. In the ...context of a GARCH-in-Mean model the empirical findings suggest the existence of the merit-order effect which is stronger in the case of wind power. Controlling for regulatory mechanisms that may affect price volatility, we find that while overall renewables have decreased price volatility, wind power tends to increase it and solar power tends to decrease it. Furthermore, during peak hours, wind and solar power generation tend to decrease price volatility, supporting the hypothesis that renewables’ output reduces the volatility of wholesale electricity prices when it is positively correlated with the electricity load. Finally, we find that the increase in the price-cap of the Greek wholesale electricity market was associated with a reduction in the volatility of wholesale electricity prices. This finding highlights the importance of the market structure and the degree of vertical integration of participants in liberalized electricity markets, which determines their behavior while also affecting market price volatility.
•The merit-order effect exists and is stronger in the case of wind power.•Wind power increases price volatility and solar power decreases it.•Depending on the penetration mix of wind and solar capacity, price volatility may, increase, decrease or not change.•Regulatory mechanisms, such as price caps, have an impact on wholesale electricity price volatility.•Wind and solar power systems should be developed in balance to achieve desired effects on electricity price and volatility.
This contribution describes the PICOSEC-Micromegas detector which achieves a time resolution below 25ps. In this device the passage of a charged particle produces Cherenkov photons in a radiator, ...which then generate electrons in a photocathode and these photoelectrons enter a two-stage Micromegas with a reduced drift region and a typical anode region. The results from single-channel prototypes (demonstrating a time resolution of 24ps for minimum ionizing particles, and 76ps for single photoelectrons), the understanding of the detector in terms of detailed simulations and a phenomenological model, the issues of robustness and how they are tackled, and preliminary results from a multi-channel prototype are presented (demonstrating that a timing resolution similar to that of the single-channel device is feasible for all points across the area covered by a multi-channel device).
The PICOSEC-Micromegas detector was developed for precise timing of the arrival of charged particles with a resolution bellow 30 ps. This contribution, after a brief introduction presents results ...concerning the PICOSEC-Micromegas response to single photoelectrons, estimation of the photoelectron yield of various photocathode types, as well as its performance to time the arrival of test beam muons. In addition, results based on detailed simulation studies and a stochastic model developed for the understanding of the detector are presented. Finally, results of studies related to the development of large scale PICOSEC-Micromegas detector for practical applications are also presented, in particular, the timing performance of a multi-channel PICOSEC prototype.
The steadily increasing luminosity of LHC requires an upgrade to high rate capability and high resolution detector technologies, for the innermost station of the muon spectrometer of the ATLAS ...experiment. For precision tracking 4 types of 2 and 3 m2 large Micromegas quadruplets will provide 8 consecutive active layers, each with 100 μm spatial resolution per individual plane. Data taken at the 120 GeV SPS muon and pion beam in August 2017 on one 2 m2 quadruplet prototype (SM2 built by the German colleagues). The full active area of the SM2 prototype quadruplet has been calibrated in the Munich Cosmic Ray Facility (CRF).
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