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.
Abstract
After the forthcoming upgrade of the LHC accelerator at CERN, its luminosity will increase up to 7.5 × 10
34
cm
−2
s
−1
. That will raise the readout rates and the background data to ...unmanageable levels for the existing ATLAS muon spectrometer. The ATLAS collaboration has proposed to replace the present small wheel muon detector with the New Small Wheel (NSW) to surpass those limitations. The new wheels consist of Micromegas (MM) and small-strip Thin Gap Chambers (sTGC). The first technology aims for precision tracking, and the last one for trigger purposes. Each wheel will be equipped with eight small and eight large sectors, while each sector will have a double MM wedge surrounded by sTGC wedges. The MM detectors for the NSW will be the largest developed Micro Pattern Gaseous Detector (MPGD) as they will cover an area up to 1280 m
2
. During detectors’ manufacture have been used various custom materials (PCBs, mesh) and innovative construction techniques. This paper describes the MM drift panels production at Aristotle University of Thessaloniki laboratory. Then will be presented resolution results of the MM detectors with cosmic-ray tests at CERN facilities.
A simulation model is developed to train Artificial Neural Networks (ANN), for precise timing of PICOSEC Micromegas detector signals. The aim is to develop fast, online timing algorithms as well as ...minimising the information to be saved during data acquisition. PICOSEC waveforms were collected and digitised by a fast oscilloscope during a femptosecond-laser test beam run. A data set comprising waveforms collected with attenuated laser beam intensity, eradicating the emission of more than one photoelectron per light pulse from the PICOSEC photocathode, was utilised by a simulation algorithm to generate waveforms to train an ANN. A second data set of multi-photoelectron waveforms was used to evaluate the ANN performance in determining the PICOSEC Signal Arrival Time, relative to a fast photodiode time-reference. The ANN timing performance is the same as the results of a full offline signal processing, achieving a timing precision of 18.3\(\pm\)0.6 ps.
The MicroMegas technology was selected by the ATLAS experiment at CERN to be adopted for the Small Wheel upgrade of the Muon Spectrometer, dedicated to precision tracking, in order to meet the ...requirements of the upcoming luminosity upgrade of the Large Hadron Collider. A large surface of the forward regions of the Muon Spectrometer will be equipped with 8 layers of MicroMegas modules forming a total active area of \(1200\,m^{2}\). The New Small Wheel is scheduled to be installed in the forward region of \(1.3<\vert \eta \vert <2.7\) of the ATLAS detector during the second long shutdown of the Large Hadron Collider. The New Small Wheel will have to operate in a high background radiation environment, while reconstructing muon tracks as well as furnishing information for the Level-1 trigger. The project requires fully efficient MicroMegas chambers with spatial resolution down to \(100\,{\mu}m\), a rate capability up to about \(15\,kHz/cm^{2}\) and operation in a moderate (highly inhomogeneous) magnetic field up to \(B=0.3\,T\). The required tracking is linked to the intrinsic spatial resolution in combination with the demanding mechanical accuracy. An overview of the design, construction and assembly procedures of the MicroMegas modules will be reported.
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