[Alice 3] Update TRK readme (#5416)

* [Alice 3] Update TRK readme

@qgp, also a test for codeownership

* Fix orthography

Author: mconcas

Detectors/Upgrades/ALICE3/TRK/README.md

@@ -10,12 +10,13 @@ Provided O2 has been compiled with upgrades enabled, it is possible to simulate
 
 ## Simulation
 TRK module is enabled via the `-m TRK` parameter.
-In case of `PIPE` to be enabled, the size of the beam pipe is automatically scaled to what is foreseen for the upgrades.
+New beampipe is currently represented by two cylindrical concentric beryllium pipes that cover by default the interaction point region.
+It is generally configurable in the code and can be activated passing `-m A3IP` to the `o2-sim` command.
 
 Typical command to generate MC data:
 ```bash
-o2-sim -m PIPE TRK [...]
+o2-sim -m A3IP TRK [...]
 ```
 
 ## Reconstruction
-Currently, the reconstruction is driven the `macro/run_trac_alice3.C`, which takes as input the hits generated by simulation. Hits can be smeared upon request (see `kUseSmearing`).
+Currently, the reconstruction is driven the `macro/run_trac_alice3.C`, which takes as input the hits generated by simulation. Hits can be smeared upon request (see `kUseSmearing`).