Fast algorithm for track segment and hit reconstruction in the CMS Cathode Strip Chambers

In this note, we propose an algorithm for fast and efficient track segment reconstruction in Cathode Strip Chambers used by CMS experiment for muon detection in the forward direction. The algorithm is designed to be CPU-efficient and is targeted for High Level Trigger (HLT, online reconstructed events pre-selection) purposes. The segment finding efficiency and the spatial resolution attainable with the proposed algorithm as well as the required CPU time are benchmarked using the MTCC data and found to surpass the HLT requirements

Efficiency of Finding Muon Track Trigger Primitives in CMS Cathode Strip Chambers

In the CMS Experiment, muon detection in the forward direction is accomplished by cathode strip chambers~(CSC). These detectors identify muons, provide a fast muon trigger, and give a precise measurement of the muon trajectory. There are 468 six-plane CSCs in the system. The efficiency of finding muon trigger primitives (muon track segments) was studied using~36 CMS CSCs and cosmic ray muons during the Magnet Test and Cosmic Challenge~(MTCC) exercise conducted by the~CMS experiment in~2006. In contrast to earlier studies that used muon beams to illuminate a very small chamber area ($< \! 0.01$~m$^2$), results presented in this paper were obtained by many installed CSCs operating {\em in situ} over an area of $\approx \! 23$~m$^2$ as a part of the~CMS experiment. The efficiency of finding 2-dimensional trigger primitives within 6-layer chambers was found to be~$99.93 \pm 0.03\%$. These segments, found by the CSC electronics within $800$~ns after the passing of a muon through the chambers, are the input information for the Level-1 muon trigger and, also, are a necessary condition for chambers to be read out by the Data Acquisition System

Effect of Gas Composition on the Performance of Cathode Strip Chambers for the CMS Endcap Muon System

The composition of the gas inside the cathode strip chambers (CSCs) defines many important performance parameters, including the gas gain and operational voltage range. Differences in these parameters were examined under variations in concentration of argon, carbon dioxide, and carbon tetrafluoride around the baseline mixture of Ar+CO2+CF4 = 40+50+10. The gas gain was found to be dependent primarily on the Ar concentration and nearly insensitive of the CF4/CO2 relative concentrations. The operational voltage range of ~370V had only a weak dependence on Ar concentration in the range of 40%-60% (-30 V for +20% change) at fixed amount of CF4, but showed about 3 times stronger dependence on the concentration of CF4 (+90 V for the concentration change from 0% to 20%) at fixed amount of Ar. We discuss 2 alternative gas mixtures Ar+CO2+CF4 = 60+30+10 and 60+35+5, which both offer performance (gas gain and plateau) very similar to that of the baseline mixture, but at 400 V lower absolute voltages

Batch Computing Facility based on PC (BCFpc)

. It is discussed the Linux PC cluster prototype at Petersburg Nuclear Physics Institute (Russia). It was enumerated the reasons why such a type of computing installation is profitable now and will be more attractive in nearest future for centralized general purpose computing in scientific applications. INTRODUCTION Last year (1997) we were faced the problem to upgrade centralized general purpose computing facility at HEP Division at PNPI. In looking for appropriate decision we took into account several hardware platforms, namely: Intel Pentium II as most wide spread microprocessor and DEC Alpha as most powerful microprocessor in a range of last years. For some comparison please see fig.1. The figure 1 shows that two microprocessor lines have almost same power: the close frequency the close power. That means we have to consider other microprocessor features. A binary program size for DEC Alpha is 1.5-3 times more than same binary program for Pentium due to RISC structure of Alpha mic..