Calorimeter Electronic Cell Structure in BRAHMS

ECAL barrel:

Electronic cells in ECAL do not exist as the separate GEANT volumes, they are fictitious, and they are the simple divisions of each Silicon plates into the 1 x 1 centimeter cell starting from the Silicon plate corner. The address of the ECAL-barrel electronic cell in barrel is calculated in subroutine CELLMAP, supported by Ecole Polytechnique.

ECAL end-cap:

Volumes ECA1 and ECA2 are divided artificially into the quadrants in subroutine
Find_ECAL_cell and each quadrant has its own coordinate system. The Silicon plates are divided into the 1 x 1 cm electronic cells in this coordinate system.

Hadron tile-scintillator calorimeter of TESLA TDR has a rather complicated scintillator light read-out, several output fibers from different tiles in depth of the sampling calorimeter structure are joined into one photodetector (so called electronic cell)..

BRAHMS calorimeter model follows this geometry/conditions, see Figure 8.

HCAL barrel: (see Figure 7 and Figure 9 for detail)

Electronic cells in HCAL have complicated shape due to the joining of a different number of scintillation tiles cited in the different sampling layers into one electronic channel.

Scintillator tiles and electronic cells are not exist as a GEANT volume in BRAHMS, they are created artificially.

Each scintillator volume (SCi) has the are size of about 3 x 1 meter, they are varied depends on the HCAL depth. It divided into tiles (from 5 x 5 cm to 20 x 20 cm), then the tiles from different sampling layers are joined in depth into one electronic cell. Sketch of one electronic cell volume is shown at Figure 8.

The database of electronic cell centers for one HCAL barrel module are calculated in subroutine HBAGEOM, it can be found in common /HBARGEOM/.

HCAL end-cap:

Volumes HCA0 - HCA4 are divided artificially into the quadrants in subroutine
Find_HCAP_cell and each quadrant has it own coordinate system. Inside this coordinate system the scintillator plates divided into tiles of differ size and then few tiles in depth are joined into one electronic cell (see Figure 10 and Figure 11 as an example).

The database of electronic cell centers for one HCAL end-cap quadrant are calculated in subroutine HCAP_CELL_DB, it can be found in common /HCAPDB/.

The parameters for databases of electronic cells are shown in the Appendix.

Figure 4: Sampling structures ECAL and HCAL

$\parbox{0.47\textwidth}{\caption{X--Y cut of calorimeter for TESLA detector }}$ $\parbox{0.47\textwidth}{\caption{Quote of Y--Z cut of calorimeter for TESLA detector. }}$

$\parbox{0.48\textwidth}{\caption{3--D view of electromagnetic calorimeter }}$ $\parbox{0.48\textwidth}{\caption{Sampli... ...ner). Tungsten is in blue, Si--detector is in green, alveolus are in yellow. }}$

$\parbox{0.48\textwidth}{\caption{3--D view of HCAL--barrel electronic cell structure for one barrel module }}$ $\parbox{0.48\textwidth}{\caption{Sketch... ...lume are in red. Sizes of tile are different in different sampling layers. }}$

Figure 9: Engineering drawing of barrel module cell structure

$\parbox{0.48\textwidth}{\caption{3--D view of HCAL--End--Cap electronic cell structure }}$ $\parbox{0.48\textwidth}{\caption{Structure of tiles in the HCAL--End--Cap module 1 (two quadrants). }}$