ENDY Station Measurement
During the Tuesday maintenace, the PCAL team(Julianna Lewis & Tony Sanchez) went to ENDY with Working Standard Hanford aka WSH(PS4) and took an End station measurement.
The ENDY Station Measurement was carried out according to the procedure outlined in Document LIGO-T1500062-v15, Pcal End Station Power Sensor Responsivity Ratio Measurements: Procedures and Log, and was completed by 11 am.
First thing we did is take a picture of the beam spot before anything is touched!
Martel:
We started by setting up a Martel Voltage source to apply some voltage into the PCAL Chassis's Input 1 channel and we record the times that a -4.000V, -2.000V and a 0.000V signal was sent to the Chassis. The analysis code that we run after we return uses the GPS times, grabs the data and created the Martel_Voltage_Test.png graph. We also did a measurement of the Martel's voltages in the PCAL lab to calculate the ADC conversion factor, which is included on the document.
After the Martel measurement the procedure walks us through the steps required to make a series of plots while the Working Standard(PS4) is in the Transmitter Module. These plots are shown in WS_at_TX.png.
Next steps include: The WS in the Receiver Module, These plots are shown in WS_at_RX.png.
Followed by TX_RX.png which are plots of the Tranmitter module and the receiver module operation without the WS in the beam path at all.
The last picture is of the Beam spot after we had finished the measurement.
All of this data is then used to generate LHO_ENDY_PD_ReportV2.pdf which is attached, and a work in progress in the form of a living document.
All data and Analysis has been commited to the SVN.
https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Projects/PhotonCalibrator/measurements/LHO_ENDY/
PCAL Lab Responsivity Ratio Measurement:
A WSH/GSHL (PS4/PS5)FrontBack Responsivity Ratio Measurement was ran, analyzed, and pushed to the SVN.
The analysis of this measurement produces 4 PDF files which we use to vet the data for problems.
raw_voltages.pdf
avg_voltages.pdf
raw_ratios.pdf
avg_ratios.pdf
All data and Analysis has been commited to the SVN.
https://svn.ligo.caltech.edu/svn/aligocalibration/trunk/Projects/PhotonCalibrator/measurements/LabData/PS4_PS5/
A surpise BackFront PS4/PS5 Responsivity Ratio appeared!!
PCAL Lab Responsivity Ratio Measurement:
A WSH/GSHL (PS4/PS5)BF Responsivity Ratio measurement was ran, analyzed, and pushed to the SVN.
The analysis of this measurement produces 4 PDF files which we use to vet the data for problems.
raw_voltages2.pdf
avg_voltages2.pdf
raw_ratios2.pdf
avg_ratios2.pdf
This adventure has been brought to you by Julianna Lewis & Tony Sanchez.
Post PCAL meeting update:
Rick Dripta and I have spoken at length about the recent End Station report's depiction of the RxPD Calibration in ct/W Plot which looks like there is a drop in the calibration and thus has changed.
This is not the case, even though we see this drop on both arms from the last 3 End Station measurements.
There is an observed change in the plots of the Working Standard(PS4)/ Gold Standard(PS5) responsivity ratio made in the PCAL lab as well. Which is why we make an in lab measurement of the Working Standard over the Gold Standard after every End Station measurement.
The timing of the change in May, the direction of the change, and the size of the change all indicate that there must be a change with either PS4 or PS5 which would have been seen on RxPD Calibration plots.
We have not seen the same change in the responsity ratio plots involving the Gold Standard (PS5) and any other integrating sphere.
This means that the observed changes in the RxPD Calibration is very likely due to a change associated with the Working Standard (PS4).
