Speaker
Description
Summary
Before starting a physics run from early 2008, all sub-detectors including their
front-end electronics should be installed and tested synthetically in-situ.
The thin gap chamber (TGC) is used for the muon-endcap trigger system. The
muon-endcap system covers the both endcaps of the detector (1.05<abs(eta)<2.4) to
detect isolated muons and give the level-1 muon trigger signal with two ranges of the
transverse momentum (pt) of low-pt > 6 GeV/c and high-pt > 20 GeV/c.
As at least three measurement points per track is necessary to identify a muon with
even such coarse momentum estimation, there are three TGC wheels per endcap (one has
three layers with triplet chambers, and the other two wheels have two layers each
with doublet chambers).
Each wheel has the radius of about 10 meter, for example pivot doublet wheel has
the radius of 11m, and due to this huge detector size, the number of channels become
about 320,000 in total. Every wheel has commonly twelve sectors. This 1/12 sector is
a construction unit for the trigger muon-endcap system for both the chambers and
electronics. The sector is also the unit for the trigger and readout system.
The analog signals from the detector are fed into the ASD
(Amplifier-Shaper-Discriminator) ASIC. There are three chains for the TGC electronics
system. The first chain is the level-1 trigger decision logic. Candidate signals of
more than 6GeV/c muon are selected by three modules (timing adjustment, bunch ID and
coincidence ASICs). These modules are mounted on the sector. The muon candidates with
more than 20GeV/c are classified by high-pt decision ASIC mounted nearby the sector.
The r-phi coincidence and the 6 classifications of pt information are performed by
the FPGA mounted in the ATLAS counting room. The resulting trigger information is
sent to the Muon Central Trigger Processor Interface (MUCTPI) in a standard format.
The second chain is for the data readout. It consists of the pipeline buffers,
derandomizers and parallel/serial converters ICs. The third chain is used for the
initialization, monitoring and controlling of the modules. The functionality of all
on-detector modules and their cablings has been inspected at the surface building
before installing to the ATLAS cavern. So far, a half of TGC chambers with
on-detector electronics have been already installed to the cavern.
In order to integrate all sub-detectors before the physics run starting from early
2008, the ATLAS commissioning run will be performed from June 2007. The main goal of
the global commissioning run from the view point of Level-1 Endcap Muon Trigger
System is to confirm the functionality of the complete chain of the TGC trigger
electronics. Before the commissioning run, the trigger signal of the events with
cosmic ray will be generated by using standalone TGC system itself, and then provided
to the sub-systems during the ATLAS commissioning run.
The scope of this presentation is the result of the global commissioning run,
especially from the viewpoint of TGC system.
