Jennie W, Jeff K, Jim Warner

Jeff noted the QPD B pitch alignment is off. 

As part of checking this I did some checks on the QPD alignments since Jeff re-aligned both QPDs on the 23rd July.

Between the 23rd and 27th July (when the shutter was closed unknowingly for a period after swapping in the permament shutter controller) QPD A was well-algined and QPD B drifted slowly down in pitch, showing some oscillation (maybe diurnal).

For context the M_M1 (located on HAM3 ISIK assembly) controls are on the left. This picomotor aligns the beam onto QPDA which sits on the HAM2 ISIJ assembly. The picomotor motor X and Y position channels H1:SYS-MOTION_C_PICO_G_MOTOR_5_X_POSITION and H1:SYS-MOTION_C_PICO_G_MOTOR_5_Y_POSITION give the relative change in the X and Y position of the mirror. Similarly on the right are the pitch and yaw of QPD B which is located on ISIK assembly in HAM3 and can be aligned using the M_C1 pico controlled mirror located in the ISIJ assembly in HAM2. This has the X and Y position readouts H1:SYS-MOTION_C_PICO_B_MOTOR_7_X_POSITION and H1:SYS-MOTION_C_PICO_B_MOTOR_7_Y_POSITION.

The channels in the image show we did not re-align the picomotors in this period (I also checked the M_B4 and M_M2 picomotors on ISIK). The temperature does not seem to change appreciably during this time and the HAM2/3 ISI and HEPI stayed isolated during this period also.

The vacuum pressure gauge I chose maybe could correlate with the beam position going down so maybe this was some bouyancy effect?

Seems unlikely though since by July 23rd the gauge was already at 6e-7 torr which is well within high vacuum pressure region.

I also took a trend of the time during which the shutter was closed here. This can be used for dark noise measurements.

Looking at the trend between when we unshuttered the laser on August 11th and today, There was some kind of drop in QPD B pitch from -0.1 to -0.4 that seemed to start on August 17th. Not sure why this happened as doesn't seem to correlate with ISIs, HEPI or picomotor changes.

We will probably need to retake any measurements we did of HAM2 after August 11th.

I have now recentred both QPD A and B using M_M1 and M_C1 respectively.