Diapositive 1

1
Quality control depends on runs processing ?
How the surveillance of the ECAL is performed at
LHC ? Requirements on the System ?
Scalability
Laser Monitoring
2
Activity CMS-ECAL surveillance
nothing to do with physics events
processing Quality control Following the ECAL
behavior in real-time
Monitoring Tasks performed during data taking ?
Short term correction coefficients ? Electronics
calibration ? Detector check ? Supervision of the
monitoring system
Types of events needed ? MATACQ events ? Laser
events (Blue and Infrared) ? Pedestal events ? PN
diodes test pulse events ? APD test pulse events
Laser Monitoring
3
Full scan of ECAL performed with the events
needed for the monitoring tasks
Monitoring sequence
Time to perform a monitoring sequence ? 30
minutes at low luminosity ? 20 minutes at high
luminosity
After each sequence, all the information is
available to perform the quality control of the
ECAL. After each wavelength and TP on a SM,
enough information is available to perform the
quality control of the SM and the Laser source.
Laser Monitoring
4
Defines a system which perform the Quality
control 1) Build the history of the ECAL
(Follows up the behavior of ECAL) 2)
Detect the Events occurring in ECAL 3)
Execute identification, validation and correction
procedures 4) Conditional data treatment
5) GUI ? Results of the Quality Control of
ECAL at the end of each
monitoring sequence ? Provide warning and alarm
messages send as soon as
possible to shift crews This system process
events in quasi real time ? Data
treatment is sequential ?
Computation of parameters is iterative
Powerful and efficient surveillance
system
Laser Monitoring
5
Processing laser runs must be rather fast
40 seconds the time needed to have the result
of the APD, PN, APD/PN0, APD/PN1 responses to
blue laser of a full SM. Time dominated by I/O
? Read the configuration files
? Read data file ? Write
reduced data
5 minutes the time needed to perform the Quality
Control of one SM ? Computation of all Pulse
Shape parameters for 2 wavelengths ? Computation
of APD,PN, APD/PN0,APD/PN1 and APD/½(PN0PN1)
responses to Laser at 2 wavelengths ?
Computation TP responses for APDs and PNs
These times are measured on a public PC with a
benchmark ROOT 150
Laser Monitoring
6
In the real world
? 36 SMs in the Barrel
? Monitoring sequence takes 30 minutes
The defined system must be scalable
We must follow the ECAL behavior in quasi real
time
3-4 minutes is the time we kept to perform the
Quality Control of one SM
The monitoring farm must be composed by 12 PCs at
least A Master PC located
in the counting room
Laser Monitoring