Sep 25 – 29, 2006
Valencia, Spain
Europe/Zurich timezone

Implementation of the Control System for the LHCb Muon Detector

Sep 27, 2006, 4:20 PM
1h 40m
Valencia, Spain

Valencia, Spain

IFIC – Instituto de Fisica Corpuscular Edificio Institutos de Investgación Apartado de Correos 22085 E-46071 València SPAIN


Rafael Antunes Nobrega (Universita di Roma I "La Sapienza")


The Muon Detector of LHCb will be equipped with about 1380 Multi-Wire Proportional Chambers. Within the Framework of the CERN Control System Project, using PVSS as the main tool, we are developing an instrument to manage such a system. Adjustment and monitoring of High and Low Voltage power supplies, on-line diagnostics and fine tuning of the Front-End read-out devices, data acquisition from the gas system and the monitoring of pressure and temperature of the experimental hall are being implemented. The system will also look after long term data archiving and alert handling. The Control System performance is currently under evaluation in a cosmic ray station. Built as a final quality control of the LHCb Multi-Wire Proportional Chambers, allowing acquisition of data from as many as 600 Front-End readout channels, the cosmic ray station is fully managed by means of a Control System prototype.


In order to manage and monitor the LHCb Muon Detector, a
Control System is now
being developed and tested. A Finite State Machine
architecture has been adopted,
following the CERN Joint Controls Project (JCOP)
recommendation: “The experiment
control systems are modelized as a hierarchy of Finite State
Machines (FSM). In
this model there is a state/command interface between a
parent and its children.
Commands are passed from a parent to its children and the
states/alarms of the
children are passed to the parent who derives its state from
those of its
children.”. Each item (Device Unit) is thought of as having a
set of stable states.
Items can move between their allowed states by making
transitions triggered either
by commands or state changes of a dependent FSM. After a
change of state the Device
Unit generates a signal to inform the Control Unit about its
state. The main
Control Unit is called Muon System. It sends commands and
receives States and
Alarms to and from a set of children Control Units (called
High Voltage, Low
Voltage, Environment Sensors, Electronics and Gas System)
which interact with the
hardware Device Units.
A first down scaled implementation of the Control System is
now being used and
tested to fully manage a cosmic ray station built for the
studies of the LHCb MWPC.
The cosmic ray stand is able to house 6 MWP chambers and
allows the acquisition of
as much as 600 Front-End channels. PVSS programs are
now being used to manage high
voltage power supplies, front-end readout devices and to
monitor the environmental
parameters. This system is giving a unique possibility to
study in details the
different features of the Control System and is an useful tool
to test its
robustness. In this document it will be described the
software tools together some
example of the studies performed with the cosmic ray stand.
Usage of the tools
developed to manage a Cosmic Ray Station, already in use
for tests and performance
valuation of the LHCb Muon Chambers, makes possible to
have a fast feedback on the
usefulness of the implemented features and to test for
robustness of the Control
System itself. Routines for calibration and diagnostics of the
electronics and for high voltage setting and monitoring have
already shown to work
very well and result of great importance for the automation
of the Muon Detector
Control System.

Primary author

Dr Davide Pinci (INFN - Sez. Roma)


Mr Francesco Iacoangeli (INFN - Sez. Roma) Mr Giacomo Chiodi (INFN - Sez. Roma) Rafael Antunes Nobrega (Universita di Roma I "La Sapienza") Mr Valerio Bocci (INFN - Sez. Roma) Mr Walter Rinaldi (INFN - Sez. Roma)

Presentation materials