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| The ISS measures the power fluctuations on a photodiode placed after the [[Mach Zender]], but before the [[Mode Cleaner]], and tries to servo that signal to zero. | ## page was renamed from PSLIntensity Stabilization Servo ## page was renamed from Intensity Stabilization Servo The ISS measures the power fluctuations on a photodiode placed after the [[Mach Zender]], but before the [[Mode_Cleaner]], and tries to servo that signal to zero. |
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| == Schematic == * [[http://www.ligo.caltech.edu/~fnocera/files/ISS%20rev%20D%20nov04.pdf|Schematic of 40m ISS servo]] - Beware that there are various "Revision D" ISS's floating around; this link is to the 40m version. There is a paper version of this at the 40m that is marked up with further modifications to the 40m ISS. * [[http://www.ligo.caltech.edu/~fnocera/files/PD%20Head.pdf|Photodiode schematic]] - This is from Flavio's website, though the direct link from his ISS page is broken due to a misspelling. |
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| || C1:PSL-ISS_INSENSPD_F || || || C1:PSL-ISS_INSENSPD_FW || || || C1:PSL-ISS_INMONPD_F || || || C1:PSL-ISS_INSENPD_FW || || || C1:PSL-ISS_CSDRIVE_F || || || C1:PSL-ISS_CSDRIVE_FW || || |
|| C1:PSL-ISS_INSENSPD_F || In-loop photodiode || || C1:PSL-ISS_INSENSPD_FW || In-loop photodiode, whitened || || C1:PSL-ISS_INMONPD_F || Out-of-loop photodiode || || C1:PSL-ISS_INMONPD_FW || Out-of-loop photodiode, whitened || || C1:PSL-ISS_CSDRIVE_F || || || C1:PSL-ISS_CSDRIVE_FW || || |
The ISS measures the power fluctuations on a photodiode placed after the Mach Zender, but before the Mode_Cleaner, and tries to servo that signal to zero.
The ISS is AC-coupled, so its purpose is not to control long-term drift. In its nominal configuration, it has gain from 1-100,000 Hz. This is to suppress the intensity noise in our measurement band.
The ISS servo sits on the PSL table; its a beige box with black front and back panels. All of the hooks for doing fast loop measurements are on that box.
The ISS actuator is the Current Shunt in the MOPA box.
Schematic
Schematic of 40m ISS servo - Beware that there are various "Revision D" ISS's floating around; this link is to the 40m version. There is a paper version of this at the 40m that is marked up with further modifications to the 40m ISS.
Photodiode schematic - This is from Flavio's website, though the direct link from his ISS page is broken due to a misspelling.
DAQ channels
C1:PSL-ISS_INSENSPD_F |
In-loop photodiode |
C1:PSL-ISS_INSENSPD_FW |
In-loop photodiode, whitened |
C1:PSL-ISS_INMONPD_F |
Out-of-loop photodiode |
C1:PSL-ISS_INMONPD_FW |
Out-of-loop photodiode, whitened |
C1:PSL-ISS_CSDRIVE_F |
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C1:PSL-ISS_CSDRIVE_FW |
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