CMS DT Electronics (CMSDTE)
- CIEMAT activities
- CMS DT Electronics description
- Useful links
- Old material repository
- CMSDTE Publications
CIEMAT group has participated in the CMS DT electronics since its conception. Our responsibilities were focused in the readout electronics, although it expanded into other electronics activities since we have been in charge of the DT electronics group coordination for a large fraction of the CMS lifetime.
The CMS DT readout electronics is in charge of the time digitization of the DT chambers signals and consequente data transmission. It is divided in several stages that aggregate the information from lower layers up to the central CMS data acquisition system. The first two levels of the DT electronics chain are the ROB (Read Out Board) and the ROS (Read Out Server) and they have been designed and produced at CIEMAT.
ROB (Read Out Board)
ROS25 (Read Out Server 25 channels board)
The Drift Tube electronics receives the signals from the anode wires through the Front End Boards (FEB) which are located inside the chamber gas volume. The FEB amplifies, shapes and discriminates the chamber signals and forwards them to the two electronic chains, the DT readout and the DT trigger.
DT read-out electronics is designed to perform time measurement of the chamber signals that will allow the reconstruction of charged particle tracks and precise momentum measurement. There are several levels of data merging in order to achieve a read-out of the full detector at a Level-1 trigger rate of 100 kHz.
Schematich view of the DT detector readout chain.
First elements are the ROBs (Read Out Boards), based on the ASIC HPTDC (High Performance Time to Digital Converter), that perform the time digitization of the hits and assign them to the Level 1 trigger. They transmit their data through a ~30 meter copper link to the 60 ROS (Read Out Server) boards located in the tower racks in the cavern. ROS boards are in charge of merging the information from one sector and perform several tasks of data reduction and data quality monitoring. Each sector event is retransmitted through an optical link to the DDU (Device Dependent Unit) boards located in the counting room. The DDU boards merge data from up to 12 ROS to build an event fragment and send it to the global CMS data acquisition system through an output at 320 MBps.
One of the key features of the DT system is its robust and reliable trigger system, with precise bunch crossing assignment. (BX stands for bunch crossing, and refers to each 25 ns unit time in which collisions may occur in CMS.) This trigger system is based on the Mean-timer algorithm and allows reconstructing tracks from the drift time measurements. For each BX the DT local trigger system provides up to two trigger segments per chamber in the Ф view, and one in the q view. In the Ф view, each trigger segment is associated with the following quantities: the BX, at which the corresponding muon candidate was produced; the position and direction in the local coordinate system of the chamber; a quality word describing how many aligned DT hits were found; and a bit flagging the segment as a first or second candidate, ordered according to their assigned quality. One set of such quantities is called a “trigger primitive”.
The trigger algorithm that provides the trigger primitives in the Ф view works in three logical steps that are sketched below. The Bunch and Track Identifiers (BTIs) search for track segment candidates made of three or four aligned DT hits within a SL in every BX. Each candidate is processed by the Track Correlators (TRACOs), which search for a proper angular matching between the candidates from the two SLs in each chamber. TRACO candidates are then sent to the Trigger Server, which performs a ghost-suppression mechanism and then selects the two trigger primitives with the highest quality.
These two trigger primitives are sent to the Sector collector boards located in the CMS tower racks. They perform trigger synchronization and send the encoded information of position, transverse momentum and track quality through high-speed optical links to the DT Regional Trigger in the counting room. The Regional Trigger builds full muon tracks and forwards the best four muon candidates to the CMS Global Muon Trigger where information is combined with that of the other muon detectors.
The main components of the DT local trigger in the Ф view of a muon chamber. The BTIs detect hit alignments within each Superlayer, the TRACOs search for proper matching between SLs and the Trigger Server selects the best two candidates in the chamber and applies a ghost-suppression algorithm.
The electronics described here is the original design from CMS with which we have been taking data during LHC physics production program called Run 1 (from 2009 to 2013). Successive upgrades in the following years are modifying this system and this are described in the DT upgrade pages.
- CMS external home page.
- iCMS page.
- CMSDOC web page.
- CMS DOCDB.
- CMS Hypernews.
- CMS CENTRE MANAGEMENT.
- CMS ONLINE.
- Padova Electronics home page.
- MAD home page.
- Martinelli's documents.
- Martinelli's files mirror.
- L. Castellani home page.
- Bologna Minicrates Assembly Site.
- Bologna Muon Trigger Group.
- Electronics for CMS Drift Tubes in Torino OLD??.
- CMS Drift Tubes in Torino.
- HEPHY Vienna Trigger web page.
- TTC System at CERN.
- CERN Digital Microelectronics Group. HPTDC Documentation.
- CERN Digital Microelectronics Group. QPLL Documentation.
- CERN Digital Microelectronics Group. GOL Documentation.
- Versatile Link Project.
- F. Montecassiano. Integration documentation web page.
- EMDB. CMS traceability.
- Bally CMS Cabling Database.
- CERN EDMS.
- PH-ESS Group. LHC rack monitoring.
- CMS RACK WIZARD.
- PH-ESE CAEN, Wiener,etc
- DT Chamber Commissioning OLD.
- DT Chamber Commissioning NEW!!!.
Since long time all the presentations and meetings information is accesible at CERN through the Indico web site.
Additionally there is an indico from CIEMAT.
CMS calendar web page also contains useful information.
- ZIP WITH VARIOUS INFO MEETINGS
- Electronics meeting summary - Padova - December 11-15, 2000.
- Electronics meeting summary - Padova - January 23, 2001
- Electronics meeting summary - Padova - March 20, 2002.
- Electronics meeting summary (Minicrate) - Bolonia - June 28, 2002
- Electronics meeting summary (Balconies and Cables) - Padova - October 16, 2002
- CMS Electronics Week - May 14 2001 (transparencies file 2 Mb)
- Muon week - "DT Electronics status" - November 5, 2001, file 1 - file 2
- Muon week - "HPTDC functional tests" - November 2001
- CMS Electronics Week - "Readout system status" - May 13, 2002
- CMS Week - "ROB operation beyond normal conditions" - June 2002
- Electronics meeting (Minicrate) - "RO System and MC operation" - Bolonia - June 28, 2002
- CMS Week - "RO status and MC production plans" - December 3, 2002
- Muon Week - "RO status" - April 10, 2003
- HPTDC Workshop - "CMS-DT Chambers Read-Out" - May 13, 2003
- Muon Week (Aachen) - "Read-Out Status" - April, 2004
- CMS Week - "Minicrate Status" - March 16, 2004
- CMS Week - "Minicrate Status" - June 8, 2004
ESR Muon DT Minicrate System (November, 3rd. 2003)
- System Overview (C. Willmott)
- Read Out System (C. Fernández)
- Trigger System Overview and Status (P. Zotto)
- Trigger Server (A. Montanari)
- Trigger Links and Synchronization (F. Odorici)
- Control System (M. Bellato)
- Test Beam Results (R. Travaglini)
- Production Plans, Reliability and Integration (C. Willmott)
Magnet Test and Cosmic Challenge (MTCC) 2006
Publications related with the activities of the CIEMAT group working in CMS electronics and upgrade can be found here: