[Dsg-rich] RICH airflow tests?

[Valery Kubarovsky]

Hello Tyler, 

For a moment right now the maximum FPGA temperature is 65F. HV is OFF. Expect higher t when HV will be ON. 
The limit is coming not only from the electronics itself but from the melting temperature of the fiber-optics cable that just touches 
the FPGA chip. The temperature that we have now is almost at the limit. I am not in favor to make any test that will increase the electronics panel t. 

I suggest another study that will help us to understand setting for the high limit temperature of your sensors. 
For a moment the difference between current t and high limit is around 5 degrees. If we will study the 
t fluctuation with time of all 16 sensors we can decrease probably this limit and get more safe run conditions. 
We can study this behavior using spring data or take new one right now with HV ON. 

Best regards, 
Valery 

> From: "Tyler Lemon" <tlemon at jlab.org>
> To: "dsg-rich" <dsg-rich at jlab.org>
> Sent: Wednesday, September 5, 2018 2:42:17 PM
> Subject: [Dsg-rich] RICH airflow tests?

> Hello Marco and Valery,

> A few months ago, you mentioned that it'd be good to figure out more precisely
> what airflow is needed to keep RICH electronics cool.

> Since there will not be beam and Hall B will be open until next week, would we
> be able to run tests this week to determine how changes in cooling airflow
> affect RICH FPGA temperatures and hardware interlock RTDs?

> The general procedure in the study would be:
> 1.) turn on HV/LV and let the EP reach its normal running temperature.
> 2..) decrease airflow to set values (decrease in ~50 slm increments?).
> 3.) Allow RICH to reach a steady temperature after change.
> 4.) Repeat steps 2 and 3 until FPGA temperatures reach some upper limit (maybe
> 75 deg C?)

> The tests would also allow better limits on the hardware interlock to be set
> because we would have data supporting at what airflow RICH electronics
> temperatures start to get too high.

> Please let us know.

> Best regards,
> Tyler

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