Synchronization methods for the PAC RPC trigger system in the CMS experiment

The PAC (pattern comparator) is a dedicated muon trigger for the CMS (Compact Muon Solenoid) experiment at the LHC (Large Hadron Collider). The PAC trigger processes signals provided by RPC (resistive plate chambers), a part of the CMS muon system. The goal of the PAC RPC trigger is to identify muons, measure their transverse momenta and select the best muon candidates for each proton bunch collision occurring every 25 ns. To perform this task it is necessary to deliver the information concerning each bunch crossing from many RPC chambers to the trigger logic at the same moment. Since the CMS detector is large (the muon hits are spread over 40 ns), and the data are transmitted through thousands of channels, special techniques are needed to assure proper synchronization of the data. In this paper methods developed for the RPC signal synchronization and synchronous transmission are presented. The methods were tested during the MTCC (magnet test and cosmic challenge). The performance of the synchronization methods is illustrated by the results of the tests

An RPC-based Technical Trigger for the CMS Experiment

In the CMS experiment, sub-detectors may send special trigger signals, called "Technical Triggers", for special purposes like test and calibration. The Resistive Plate Chambers are part of the Muon Trigger System of the experiment, but might also produce a cosmic muon trigger as Technical Trigger to be used during the commissioning to the detectors, the CMS magnet Test Cosmic Challenge and the later running of CMS. The proposed implementation is based on the development of a new board, the RBC Balcony Collector (RBC); the test results on prototypes and their performance during the recent CMS Cosmic Challenge are presented

JTAG Test System for RPC Muon Trigger at CMS experiment

Theoretical and practical realisation of the JTAG testing system for the RPC Muon Trigger of the CMS experiment at the LHC accelerator at CERN laboratory (Geneva) is presented. The paper covers issues related to tests of connections of the printed circuit boards (PCB) of the RPC Trigger. Functionality tests of devices and modules were performed. Special tests were designed for large PLD FPGA. Testing environment for the JTAG model is discussed. The model is based on some existing and some newly developed testing algorithms. Practical system realisation is presented. The system consists of the hardware interface and the software layer. Software was built using C++ object oriented language and databases. Exemplary tests of the RPC Muon Trigger electronics was performed and the results were given

Radiation tolerant design of RLBCS system for RPC detector in LHC experiment

This paper describes the design of the Link Box Control System for the RPC Detector (RLBCS), emphasizing the features needed to assure reliable operation in the irradiated environment of the RPC detector and its neighbourhood. The development process required to balance different factors- radiation hardness, reliability, flexibility, firmware upgrade possibilities, diagnostic features. The final design presented in the paper is a result of compromise between the above requirements

RPC Link Box Control System for RPC Detector in LHC

This paper describes the RPC Link Box Control System (RLBCS) developed for the RPC muon trigger 1 in the CMS experiment on LHC collider under construction in CERN (Geneva). RLBCS subsystem is responsible for relatively slow, bidirectional communication between the link electronics placed on detector and devices of CMSDetector Control System (DCS) located in the control room. The RLBCS is used for diagnostic and control purposes, and therefore it is essential for the RPC muon trigger. The RLBCS is also responsible for configuration of the FPGAs in the RPC link electronics, working in the harsh, irradiated environment. Additionally most part of the RLBCS itself works in the irradiated area, so assuring its reliable operation required some special solutions. All the above factors make this subsystem an important and non-trivial task in the CMS RPC muon trigger development