[Clas12_first_exp] [EXTERNAL] trigger bits

[Marco Mirazita]

Hello everyone,
I want to study the noise on the rich readout using random trigger 
events.
Can you please tell me what trigger bit should I select?
For the moment, I'm interested in the rg-a fall 2018 (eg run 5038) but I 
may want to extend the study to other run periods.
Looking at the data, it looks like bits 31,39,44 don't have any on-time 
signal, but there is no explanation for them in the trigger_version 
spreadsheet.
Thank you,
Marco