[Dsg-rich] Nitrogen test in the RICH

[Marco Mirazita]

Hi all,
the N2 system in the RICH run for most of the weekend.
The system was started at 13:50 on Friday with two lines feeding 24 slm 
each.
The initial humidity was about 37%, then started to drop quite rapidly.
We reached a minimum level of about 2% at 4:30 am on Saturday night, 
then started to slowly increase because of the reduction in the N2 flow 
due to the dewar that was almost empty.
At 10 am on Sunday the flow was about 1.5 slm and the humidity was about 
9%.
See the elog entry https://logbooks.jlab.org/entry/3490201 and 
https://logbooks.jlab.org/entry/3490246 for more details.

The plan for next week is to restore the system as soon as possible, 
then fill again the RICH and run for some time at the nominal flow level 
of about 20 slm total.
To do this a new dewar is necessary.

Best regards,
Marco