Pcal Team,
Calibration:
We calibrated the Photon calibrator readback photodiodes at EndX and the new displacement calibration factors for TxPD and RxPD compared to the last calibration are reported below. The difference in the calibration factors are within our reported uncertainty. These number are also uploaded to DCC document T1500252. A detail report of the calibration factors, optical efficiency and other intermediate calculations is attached to this alog.
2015/08/04 |
2015/05/20 |
|
TxPD(m/V) |
8.428E-13/f^2 +/- 0.59% |
8.464E-13/f^2 +/- 0.59% |
RxPD(m/V) |
6.730E-13/f^2 +/- 0.68% |
6.722E-13E-13 +/- 0.68% |
Other Details:
Beam Clipping:
We had a beam clipping issue at ENDX (alog #19899) and fixed it after aligning the beam using the steering mirror on transmitter module last week. (alog #20054). We checked if this alignment was still good by measuring the power at the transmitter side and the receiver side and alignment seems to be good. In addition, we also measured the output power of the laser before the AOM. The measured value (1.6 W) was consistent with what we measured last time on 04/10/2015.
AA Chassis:
PCAL AA chassis had 3 channels which were either railing or dead and this issue has been reported in a separate alog (LHO alog #20259) and a fix is underway.
BNC-DB9 Chassis:
We had installed a DB9-BNC chassis to route the working standard signal (for calibration) and AOM drive signal (monitoring) to the AA chassis few weeks ago. These chassis were not tested after installation so we used a calibrated voltage source to test the chassis before proceeding with the calibration. 1 V of calibrated source gave us ~1637 cts on our readback channel.
OFS Transfer Function:
As a part of calibration we also measured the transfer function of the Optical Follower Servo and a plot is attached. OFS has a unity gain of 100 KHz with a phase margin of about 62 degrees.
