BMT_HitProcess
The barrel micromegas hit process routine includes:
- determination of the sector: the tile number is calculated using the phi coordinate of the hit
- conversion of the deposited energy into a number of electrons: the deposited energy provided by Geant4 is used to estimate the average number of electrons created in the MM sensitive volume (knowing the mean ionization potential of the gas). If the deposited energy is smaller than the ionization potential (roughly 25 eV), then the hit is discarded
- generation of a transverse diffusion: for each electron created at the previous step, a transverse diffusion is generated on a Gaussian. The width of this Gaussian is obtained by the standard formula for diffusion, i.e. proportional to the square root of the distance between the interaction point and the micro-mesh.
- shift of the position due to the Lorentz angle: for "z" detectors, the presence of the longitudinal magnetic field induces a Lorentz angle which shifts the position of the signal. This shift is calculated for each electron, and added to the transverse diffusion estimated at the previous step. Here again, the shift due to the Lorentz angle depends on the distance between the interaction point and the micro-mesh. The Lorentz angle has been estimated to 20 degrees using a Garfield simulation.
- determination of the strip: the final transverse position of each electron (after transverse diffusion and potential Lorentz angle) is converted into a strip number (the closest one).
- determination of the energy collected on the closest strip: if N electrons have been created for the deposited energy Edep, the energy associated to the current strip is Edep/N. Note that this assumes no gain fluctuation. A more realistic treatment (not yet implemented) would be to generate a gain for each electron, using a Polya distribution.
- check of the acceptance: if the strip number is negative or larger than the total number of strips, it is discarded (associated value is -1).
- Author
S. Procureur, G. Charles, M. Ungaro -
mail: sebas.nosp@m.tien.nosp@m..proc.nosp@m.ureu.nosp@m.r@cea.nosp@m..fr, gabri.nosp@m.el.c.nosp@m.harle.nosp@m.s@ce.nosp@m.a.fr, ungar.nosp@m.o@jl.nosp@m.ab.or.nosp@m.g
Definition at line 42 of file BMT_hitprocess.h.
Inheritance diagram for BMT_HitProcess:
1.8.11
