RPC cosmic ray tests in the ATLAS experiment Chiodini, G.; Aielli, G.; Aloisio, A. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2007, Letnik:
581, Številka:
1
Journal Article
Recenzirano
Extensive tests with cosmic rays were performed with Resistive Plate Chamber (RPC) trigger chambers belonging to 6 muon stations of sector 13 installed in the ATLAS muon spectrometer. We illustrate ...the results of this pre-commissioning phase, which represents a test bench for the final commissioning of the ATLAS RPC system with cosmic rays.
The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton–proton collisions from beams crossing at 40
MHz. At the design luminosity of
10
34
cm
-
2
s
-
1
there are on average ...23 collisions per bunch crossing. A three-level trigger system will select potentially interesting events in order to reduce the readout rate to about 200
Hz. The first trigger level is implemented in custom-built electronics and makes an initial fast selection based on detector data of coarse granularity. It has to reduce the rate by a factor of
10
4
to less than 100
kHz. The other two consecutive trigger levels are in software and run on PC farms. We present an overview of the first-level trigger system and report on the current installation status. Moreover, we show analysis results of cosmic-ray data recorded in situ at the ATLAS experimental site with final or close-to-final hardware.
The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting ...events in order to reduce the read-out rate to about 200 Hz. The first trigger level is implemented in custom-built electronics and makes an initial fast selection based on detector data of coarse granularity. It has to reduce the rate by a factor of to less than 100 kHz. The other two consecutive trigger levels are in software and run on PC farms. We present an overview of the first-level central trigger and the muon barrel trigger system and report on the current installation status. Moreover, we show analysis results of cosmic-ray data recorded in situ at the ATLAS experimental site with final or close-to-final hardware.
The detector at CERN's large hadron collider (LHC) was exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting events in ...order to reduce this rate to 100- 200 Hz. A trigger decision is made by the Level-1 central trigger processor (CTP) reducing the incoming rate to less than 100 kHz. The Level-1 decision is based on calorimeter information and hits in dedicated muon trigger detectors. The final Level-1 trigger system is currently being installed in the experiment with completion expected in autumn 2007. Cosmic ray data are regularly recorded as an increasing fraction of the trigger system comes online. We present an overview of the Level-1 trigger system architecture and report on the installation and commissioning process at the ATLAS experimental site. Emphasis is put on the integration of the CTP with the calorimeter and muon trigger systems. We show results from analyses of cosmic ray data recorded in situ and verify, where possible, that the Level-1 trigger meets the requirements and will be ready for data taking.
The ATLAS Muon Spectrometer, currently in the installation phase, uses dedicated detectors to be able to trigger on high transverse momentum muons in the range 6 - 20 GeV/c Resistive Plate Chambers ...(RPC) are equipping the Barrel region in the middle and outer station, while precision chambers (Monitored Drift Tubes, MDT) are present also in the inner layer. The RPCs have the required timing and spatial resolution of about 2ns × 1 cm, to be able to associate the muon to the correct bunch crossing and provide the second coordinate measurements to the MDTs. In order to successfully commission the chambers, cosmic runs are taken to check and validate the readout and trigger chain, and cosmic rates are measured and compared against values obtained with a cosmic ray Montecarlo generator and full detector simulation. The first part of the detector under commission is the set of horizontal chambers positioned between the feet of the detector. The first results obtained in the ATLAS cavern will be presented. The first cosmic data taking collects signals from chambers arranged in six trigger towers, covering about one quarter of the full detector lenght. The experience gained on this small part of the detector will be very useful to define the commissioning work for the whole detector.
The first commissioning test of three muon towers of the ATLAS Muon Spectrometer, installed in the cavern, was carried out. The stations under test belong to the barrel sector 13, which is a large ...sector. A muon tower consists of three stations: the Inner, the Middle and the Outer, starting from the interaction point. The Barrel Inner Large (BIL) stations are constituted by MDT chambers; the Barrel Middle Large (BML) stations by MDTs assembled between two RPC chambers; and the Barrel Outer Large (BOL) stations by MDTs with only one RPC mounted downstream. Specific Level-1 trigger algorithms have been studied to trigger on cosmic rays and implemented to commission the muon stations. Comparison between the measured trigger rate and the simulated results will be presented. Moreover, the RPC performances have been studied by comparing the MDT track extrapolations with the firing RPC readout strips. The RPC detection efficiency is evaluated in the eta measuring view, resulting as a combination of gas volume efficiency and Front-End efficiency.
The ATLAS first level trigger is designed to reduce the LHC interaction rate from 1 GHz to 75–100 kHz. The first level muon trigger in the barrel is described together with test beam results and ...current commissioning and integration status at CERN.
The ATLAS detector at CERN's Large Hadron Collider (LHC) will be exposed to proton-proton collisions from beams crossing at 40 MHz. A three-level trigger system will select potentially interesting ...events in order to reduce the readout rate to about 200 Hz. The first trigger level is implemented in custom-built electronics and makes an initial fast selection based on detector data of coarse granularity. It has to reduce the rate by a factor of 104 to less than 100 kHz. The other two consecutive trigger levels are in software and run on PC farms. We present an overview of the first-level central trigger and the muon barrel trigger system and report on the current installation status. Moreover, we show analysis results of cosmic-ray data recorded in situ at the ATLAS experimental site with final or close-to-final hardware.
COVID-19 case fatality rate in hospitalized patients varies across countries and studies. Reliable estimates, specific for age, sex, and comorbidities, are needed to monitor the epidemic, to compare ...the outcome in different settings, and to correctly design trials for COVID-19 interventions. The aim of this study was to provide population-based survival curves of hospitalized COVID-19 patients.
A cohort study was conducted in three areas of Northern Italy, heavily affected by SARS-CoV-2 infection (Lombardy and Veneto Regions, and Reggio Emilia province), using a loco-regional COVID-19 surveillance system, linked to hospital discharge databases. We included all patients testing positive for SARS-CoV-2 RNA by RT-PCR on nasopharyngeal/throat swab samples who were hospitalized from 21 February to 21 April 2020. Kaplan-Meier survival estimates were calculated at 14 and 30 days for death in any setting, stratifying by age, sex, and the Charlson Index.
Overall, 42,926 hospitalized COVID-19 patients were identified. Patients' median age was 69 years (IQR: 57-79), 62.6% were males, and 6.0% had a Charlson Index ≥3. Survival curves showed that 22.0% (95% CI 21.6-22.4) of patients died within 14 days and 27.6% (95% CI 27.2-28.1) within 30 days from hospitalization. Survival was higher in younger patients and in females. The negative impact of comorbidities on survival was more pronounced in younger age groups.
The high fatality rate observed in the study (28% at 30 days) suggests that studies should focus on death as primary endpoint during a follow-up of at least one month.
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