Initial Simulation Details
The initial geometry involves only the calorimetry in approximate form: layers are
cylinders and there are no cracks in the barrel or endcap devices. Material data was
generated using the PEGS preprocessor for EGS. A sample geometry
file is shown here.
Strawman Detector Designs
Two reference ("strawman") geometries have been created to get the show on
the road: a small and a large
detector, with drawings.
These were changed in detail after the Dec '98 workshop. The ascii detector files are now
available for small, large.
Note: at the moment, the ascii files have the last word on what
gets simulated. They do not match in detail the tables above! Check the ascii files to
really know what's defined.
(The first descriptions of small and large and versions of the ascii detector in file
are still available for download for the small
and large detectors.
Readout Issues:
- I/O currently happens at the digization phase of simulation and is output as an ASCII file.The tracking systems and calorimeters all carry along the
MC truth history (which particle created tracker hits and which contributed how much
energy to each calorimeter hit).
- Calorimeter ID's are defined as binary:
-
| Field Size (bits) |
Bit location |
Meaning |
| 3 |
0-2 |
phi bin width |
| 9 |
3-11 |
theta bin |
| 9 |
12-20 |
phi bin |
| 7 |
21-27 |
layer (each system starts at zero) |
| 2 |
28-29 |
EM, HAD, MU, LUM |
| 1 |
30 |
north/south |
| 1 |
31 |
EC/barrel |
- Tag definitions:
- Subsystem Definitions:
- EM, HAD, MU, LUM = (0,1,2,3)
- South = 0 (-z), north = 1 (+z)
- barrel = 0, EC = 1
- Reconstructing positions of Calorimeter Tags
- the angular widths are now given only by one parameter and bins are calculated starting
at theta=0 and phi=0. Bins are in constant cos(theta).
- cos(theta) = 1 - Seg*(0.5 + bin)
- inner and outer tower radii are given by the starting radius and cell thickness
- Muon ID's are also defined as binary:
-
| Field Size (bits) |
Bit location |
Meaning |
| 12 |
0-11 |
theta (barrel) or x (EC) bin |
| 12 |
12-23 |
phi (barrrel) or y (EC) bin |
| 5 |
24-28 |
layer |
| 1 |
30 |
north/south |
| 1 |
31 |
EC/barrel |
- muon hits are currently defined as rectangles in (z,phi) or (x,y). All layers have both
readouts. It is up to the user to decide which layers have which style of readout
and to amalgamate into strips where needed.
- Reconstructing Muon strip positions
- the strip values have been offset by 1000 cm
- position = strip_width * value - 1000
- phi position is measured in cm running around the radius (ie must divide by the layer
radius to get the angle phi)
- Tracker/VXD hits are the space points on the layer cylinders plus deposited energy.
These also have binary tags:
-
| Field Size (bits) |
Bit location |
Meaning |
| 8 |
0-7 |
layer |
| 2 |
28-29 |
system: Tracker=0; VXD=1 |
| 1 |
30 |
north/south |
| 1 |
31 |
EC/barrel |
- These ASCII files are then translated to other output formats for analysis. At the time
of writing we have parsers for Java and Root. PAW coming soon.
R.Dubois Last Modified: 01/13/04 12:41