The new generation of particle physics experiments at current and future colliders demands more and more robust detectors. A proposed solution to the stringent requirements are the Small-pad ...Resistive Micormegas. This technology is being developed during recent years, in the framework of the new R&D project RHUM. Different resistive schemes have been implemented. The different behaviours of the embedded resistor layout and the Diamond-Like Carbon (DLC) uniform layers scheme have been studied. Results at very high rate are shown. HV stability studies with two different gases are reported.
Pixelated resistive Micromegas detector for high-rate environment Alviggi, M.; Camerlingo, M.T.; Pietra, M. Della ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2022, Letnik:
1041
Journal Article
Recenzirano
The R&D work reported in this paper has been devoted to the production and test of pixelated resistive micromegas detectors able to track particles in a high-rate environment, up to 10MHz/cm2, ...keeping a stable gain and a good spatial resolution. To pursue our goal, we had to reduce the occupancy by increasing the detector granularity and this has been done by changing the read-out anodes from the usual strips to pads. This minor change in the electrodes layout drastically increased the difficulty of implementing a resistive structure to protect the anodes from sparking. We present the results of the tests performed on four prototypes, with different protection schemes, showing it is possible to reach the desired rate with high gain, high efficiency and good position resolution. The response to X-rays from low (55Fe source) to high (X-rays generator) rates, as well as to beams of ionizing particles is reported.
During the LHC Run-1, Grid resources in ATLAS have been managed by the PanDA and DQ2 systems. In order to meet the needs for the LHC Run-2, Prodsys2 and Rucio are used as the new ATLAS Workload and ...Data Management systems. The data are stored under various formats in ROOT files and end-user physicists have the choice to use either the ATHENA framework or directly ROOT. Within the ROOT data analysis framework it is possible to perform analysis of huge sets of ROOT files in parallel with PROOF on clusters of computers (usually organised in analysis facilities) or multi-core machines. In addition, PROOF-on-Demand (PoD) can be used to enable PROOF on top of an existing resource management system. In this work, we present the first performance obtained enabling PROOF-based analysis at CERN and in some of the Italian ATLAS Tier-2 sites within the new ATLAS workload system. Benchmark tests of data access with the httpd protocol, using also the httpd redirector, will be shown. We also present results on the startup latency tests using the new PROOF functionality of dynamic workers addition, which improves the performance of PoD using Grid resources. These new results will be compared with the expected improvements discussed in a previous work.
Muon beams are customarily obtained via K/πdecays produced in proton interaction on target. In this paper we investigate the possibility to produce low emittance muon beams from electron–positron ...collisions at centre-of-mass energy just above the μ+μ− production threshold with maximal beam energy asymmetry, corresponding to a positron beam of about 45GeV interacting on electrons on target. We present the main features of this scheme with an outline of the possible applications.
In the ATLAS computing model Grid resources are managed by PanDA, the system designed for production and distributed analysis, and data are stored under various formats in ROOT files. End-user ...physicists have the choice to use either the ATHENA framework or directly ROOT, that provides users the possibility to use PROOF to exploit the computing power of multi-core machines or to dynamically manage analysis facilities. Since analysis facilities are, in general, not dedicated to PROOF only, PROOF-on-Demand (PoD) is used to enable PROOF on top of an existing resource management system. In a previous work we investigated the usage of PoD to enable PROOF-based analysis on Tier-2 facilities using the PoD/gLite plug-in interface. In this paper we present the status of our investigations using the recently developed PoD/PanDA plug-in to enable PROOF and a real end-user ATLAS physics analysis as payload. For this work, data were accessed using two different protocols: XRootD and file protocol. The former in the site where the SRM interface is Disk Pool Manager (DPM) and the latter where the SRM interface is StoRM with GPFS file system. We will first describe the results of some benchmark tests we run on the ATLAS Italian Tier-1 and Tier-2s sites and at CERN. Then, we will compare the results of different types of analysis, comparing performances accessing data in relation to different types of SRM interfaces and accessing data with XRootD in the LAN and in the WAN using the ATLAS XROOTD storage federation infrastructure.
In the present fMRI study the issue of the specific cortices activation during imagery generation in different sensory modalities is addressed. In particular, we tested whether the vividness ...variability of imagery was reflected in the BOLD signal within specific sensory cortices. Subjects were asked to generate a mental image for each auditory presented sentence. Each imagery modality was contrasted with an abstract sentence condition. In addition, subjects were asked to fill the Italian version of the Questionnaire Upon Mental Imagery (QMI) prior to each neuroimaging session. In general, greater involvement of sensory specific cortices in high-vivid versus low-vivid subjects was found for visual (occipital), gustatory (anterior insula), kinaesthetic (pre-motor), and tactile and for somatic (post-central parietal) imagery modalities. These results support the hypothesis that vividness is related to image format: high-vivid subjects would create more analogical representations relying on the same specific neural substrates active during perception with respect to low-vivid subjects. Results are also discussed according to the simulation perspective.
In 2012, 14 Italian institutions participating in LHC Experiments won a grant from the Italian Ministry of Research (MIUR), with the aim of optimising analysis activities, and in general the Tier2 ...Tier3 infrastructure. We report on the activities being researched upon, on the considerable improvement in the ease of access to resources by physicists, also those with no specific computing interests. We focused on items like distributed storage federations, access to batch-like facilities, provisioning of user interfaces on demand and cloud systems. R&D on next-generation databases, distributed analysis interfaces, and new computing architectures was also carried on. The project, ending in the first months of 2016, will produce a white paper with recommendations on best practices for data-analysis support by computing centers.
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