[Solid_tof] solid mrpc trigger response

[Zhiwen Zhao]

hi, Yi and Mickey

As you may know, we plan to use MRPC as part of SoLID SIDIS trigger to 
reject photons
To do the study, I simulated how particle deposit energies in mrpc gas 
layers
and assumes the MRPC response is something like below
==========================================================================================
1. at least a single particle having energy deposition > 16eV for 
ionization in one layer of Freon gas will fire this layer	
2. the mrpc fires when the number of layers fires is at least n
3. I am guessing we can start the study with n=5 for trigger threshold. 
We could use other value for charge particle detection.
==========================================================================================
Do you have any comment or suggestion?

Another thing is about mrpc segmentation
Because of low energy photons could be dominant background for mrpc, the 
number and direction of segmentation may affect
how high the occupancy by background is and how trigger performs.
I see PreCDR has the design 50 supermodule and 3 modules per super 
module, total 150 modules
I assume the supermodules is segmented along azimuthal direction and 3 
modules in each supermodule is along radial direction?
Is there any freedom of changing the segmentation if trigger demands?
Will that impact charge particle detection?

Thanks

Zhiwen