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

An ME234/2 EMU chamber with a prototype copper cooling plate mounted on frame. Cooling plate is fully instrumented with cathode front-end boards, ALCT and low-voltage distribution board. All cable harnesses and strain reliefs are in place.

Taken at Lab 7, Fermilab. CMS EMU on-chamber integration project

An ME234/2 EMU chamber with a laminated prototype cooling plate mounted. Dummy cathode boards and cathode board covers are installed.

Taken at Lab 7 at Fermilab, in August 2000. Part of EMU on-chamber integration

An Endcap Muon CSC with a prototype cooling plate mounted on the chamber frame. Visible are the aluminum cover supports that mount between the cathode front-end boards.

EMU CSC copper cooling plate mounted on chamber, no electronics installed

Modern high-availability multi-stage power distribution system for the CMS phase-2 upgrade

The operation of CMS at the HL-LHC requires an upgrade of the readout electronics. These new modern micro-electronics require power at precise voltages between 1.2 V and 2.5 V. We will deliver this power using a 3-stage system, comprising AC-DC conversion to 380 V DC followed by radiation-tolerant 12 V DC-DC power converters feeding radiation-hard point-of-load DC-DC converter. We have studied an industrial 380 V AC-DC conversion system, featuring hot-swappable 3 kW power modules, stackable up to ∼1 MW system. Such systems are candidates for the first conversion step, feeding custom power supplies accepting 400 V DC input voltage. Our tests on one of the commercially available systems purchased from Eltek demonstrated that the system complied with our requirements, most notably in terms of maintainability, availability and power quality. A few measurement plots perceived by authors as particularly interesting are discussed in this contribution.ISSN:1748-022