[Yokozawa, Yasui, Ushiba]

Abstract:
We rearanged PR3 OpLevs to avoid sticking.out QPDs form Optical tables on the pylon.
Rearangement was succeeded and new wind shield made by aluminum foils were constracted.

Detail:
<Motivation>
Since PR3 OpLev output beam was passing through the very edge of the viewport and QPDs for the tilt OpLev was installed sticking out from the optical table.
So, we moved injection beam position and rearaged optical layout to avoid protrusion.

<What we did>
We moved injection beam position and adjusted the injection angle in order not to clip the beam.
After that, we rearange the reciever side optical components.
To avoid changing calibration factors, we set a lens, mirror, and QPD for length sensing OpLev as follows:
*Distance between BS and lens: 25 mm
*Distance between lens and mirror: 215 mm
*Distance between mirror and QPD: 215 mm
According to the klog19613, total diatance from BS to QPD is 455 mm, which is the same as the current setup.

After that, we constracted wind shield for OpLevs.
In this time, we didn't make windshield between viewport flanges and pylons because we will soon have leak test of central area after vacuum evacuation.
So, we need to make it after cnfirming vacuum leak was not there.
In addition, we made aluminum foil wind shield so as to be easily open by only detaching white tapes.
So, please do not touch pink tapes on the windshield, otherwise the windshield will be broken and need to be repaired from the begining. 

After the work, I recovered the alignment and current setpoint of PR3 is a good enough to lock the X arm.