cheryl.vorvick@LIGO.ORG - posted 15:28, Thursday 02 March 2017 (34478)
IMC beam spot postion measurements:
IMC beam spot measurements - comparing 24 Feb 2017 to 10 Nov 2016:
| 24-Feb-17 | 10-Nov-16 | change | |||
| p2l or y2l gain | alpha | beam spot from center ,mm | previous measurement (cold) | mm | |
| MC1 P | -1.2 | -0.057 | +2.4 | +2.4 | 0 |
| MC1 Y | 1.695 | 0.081 | +3.4 | +3.0 | +0.4 |
| MC2 P | +7.6 | ||||
| MC2 Y | -0.80 | ||||
| MC3 P | -1.147 | -0.055 | +2.3 | +2.3 | 0 |
| MC3 Y | -2.87 | -0.137 | -5.8 | -5.1 | -0.7 |
| alog 31392, alog 31402 |
I incorrectly changed coil gains instead of pitch-2-length or yaw-2-length gains, and then made adjustments to my results.
MC1 and MC3 have two signal paths from excitation to coil output (that get summed before the coil input) are:
- EXC -> a2a_gain -> eul2osem_a_gain (summed with other path) -> coil_gain -> coil_output
- EXC -> a2l_gain -> eul2osem_l_gain (summed with other path) -> coil_gain -> coil_output
I created these signal paths and used them to calculated the p2l or y2l gain changes that produce the same coil output that I achieved by changing coil gains, and then used those p2l and y2l calculated values to get the beam spot position.
MC2 data was collected, results to be posted later.