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Entry   long run to test the appearance of high frequency noise, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics long_run_with_different_FPC_power.png
    Reply   long run to test the appearance of high frequency noise, posted by Ronic Chiche at ThomX igloo about lasers and optics | detectors and electronics 2025-07-10_-_long_run.png
Message ID: 439     Entry time: Wed Jul 9 18:11:59 2025     Reply to this: 440
 Author: Ronic Chiche 
 Status: Fixed 
 Type: info 
 Category: lasers and optics | detectors and electronics 
 Location: ThomX igloo 
 Title: long run to test the appearance of high frequency noise 

Today with Daniele, we did 6 long runs at different power (23kW, 46kW, 66kW, 73kW, 92kW, 92kW)

All the lock loss in between these several runs are due to FPC locking parameters change.
most of the few lock losses during the stable power duration, are due to 20Hz oscillation noise or because we forgot to center properly the PZT in its range (operator faults).

the 4 first runs (23kW, 46kW, 66kW, 73kW) are using the PID : (P=0.1 / I=0.0015 / D=1.5) without the additionnal optical attenuator placed after the diffuser.

the 5th run (92kW) is using the PID : (P=0.1 / I=0.0015 / D=1.5) with the additionnal optical attenuator placed after the diffuser.

the 6th run (92kW) is using the PID : (P=0.05 / I=0.0005 / D=0.6) and obviously a different diffuser position) with the additionnal optical attenuator placed after the diffuser.

surprisingly, we never saw any high frequency noise during the day !

to be noticed : the electron machine was OFF / the day was sunny without wind / almost nobody was working in the bunker.

Attachment 1: long_run_with_different_FPC_power.png  61 kB  | Show | Show all
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