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Reports until 17:07, Wednesday 20 November 2024
H1 PSL
daniel.sigg@LIGO.ORG - posted 17:07, Wednesday 20 November 2024 - last comment - 17:15, Wednesday 20 November 2024(81390)
Fast time domain trace of the PMC glitches

The attached plots show the PMC mixer error signal and the ISS PDB readout. The later implements a fair amount of whitening so tends to fluctuate at a slow rate compared to the glitches.

The PMC error signal goes as high as 1.25Vpp during a PDH sweep. The channel recorded by the DAQ has a lot of gain and clips around +/-80mV, but it is calibrated correctly. So, the calibration is 1.25V/1.19MHz = 1.05V/MHz.

First plot shows a train of glitches, going as high as ~70mVpk (or ~70kHz).

The second plot shows a zoomed in version of a glitch of about the same size. The PMC servo drives the PZT with a 3.3K series resistor forming a ~1kHz low pass with the PZT capacitance of ~45nF. This yields a chracteristic time constant of ~150us. The glitches as seen by the PMC mixer are at least a few times faster than this.

The third plot shows a PDH scan.

The forth plot shows a typical trace when nothing happens.

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daniel.sigg@LIGO.ORG - 17:15, Wednesday 20 November 2024 (81392)

A tend plot of a glitch train together with some PEM channels.

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