NAOJ GW Elog Logbook 3.2
In order to check if the spiky noise decreases after placing the clean booth, long time acquisition of AC noise was performed (1 hour).
I couldn't find spikes, but we see a strange beaviour: the noise increase with time to a very high level (1mV std). Then another acquisition of 5 minutes was performed and it can be seen the noise suddenly decrease alone at a certain point. I'm trying to find a reason to this strange behaviour. The booth fan are ON, I think they never stop alone. Maybe some fan of the air conditioning or other noisy devices, I don't know.
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I used a vacuum cleaner to clean the floor inside the clean booth and around it. The floor is not smooth, it's not easy to remove all the dust.
Today (Monday 29th) I acquired an hour of noise in the exactly same condition and I found 18microV of noise and no spiky noise at all. The only thing that changed since last time is that the system has been at rest for the weekend, about 48 hours.