Proton induced radiation damage studies on plastic scintillators for the Tile calorimeter of the atlas detector

Figure 2-4: Representation of a Tile Module and its various components 
2.2.2.
 
The Gap regions 
In the region between the central and extended Tile barrels, there is a 68 cm thick 
gap which contains the services to the inner detector systems, the read-out 
electronics crates and the Liquid Argon (LAr) cryostat flange. These result in a 
build-up of “dead material” within the detector where the reconstructed energy 
signal may be lost.
In order to correct for this energy loss across the gap, the Intermediate Tile 
Calorimeter (ITC) detector is employed which uses additional plastic scintillator 
plates to sample the energy across the gap. The scintillators are coupled to WLS 
fibers and are encased in aluminium cans. The fibers then lead to PMT’s and the 
signal is digitized using the same read-out electronics as those used in the Tile 
barrels.
The scintillators of the ITC are referred to as the Gap scintillators ( E1 and E2) 
and the Cryostat scintillators (E3 and E4). The Gap scintillators are located 
between the central and extended Tile Barrels, covering the η region from 1.0 to 
1.2, and are used to correct the hadronic energy response. The Cryostat, or Crack, 

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scintillators are located between the central and endcap electromagnetic 
calorimeter cryostats, covering the η region from 1.2 to 1.6, and are used for 
correcting the electromagnetic energy response.
[10]
Figure 2-5: Layout of the ITC scintillators relativ e to the cells of the Tile Calorimeter 
barrels 
In addition to the Tile Calorimeter and 
the ITC, the Minimum Bias Trigger 
system 
also 
employs 
plastic 
scintillators. The Minimum Bias 
Trigger Scintillators (MBTS) are 
located within the Gap, at a smaller 
radius from the beam pipe, near the 
inner pixel detector. They cover the η 
region from 2.09 to 3.84. These 
scintillators form part of the first level 
hardware trigger system and provide a 
trigger signal for when to record 
events which have potential for 
physics 
of 
interest. 
[9] 
The 
photograph in radial distribution of the MBTS and 
cryostat scintillators in the Gap region.