alexan.staley@LIGO.ORG - posted 10:06, Thursday 08 January 2015 - last comment - 10:10, Thursday 08 January 2015(15937)
Y arm IR low loss point and alignment repeated
Evan, Alexa, Thomas
We repeated the Y arm loss measurement that we did yesterday in alog 15919. We followed the same steps and found: green TR buildup was 1.018, IR TR buildup was 11.2(0.5), Poff = 1303(5), and Pon = 1251(5). This gives a loss of 155(19)ppm, which is still suffeciently low, and within uncertainity of yesterday's measurement. This confirms that we are aligned to a good spot, and there is no need to adjust the green QPD offsets.
Just for reference: when we run the ditherAlign TMSY script the maximum normalized PD1, PD4 values are 1.38(0.05), 1.09(0.05) respectively.
Attached is a script which gives the algorithm for computing the loss. The
uncertaintiespackage is required.