(Keita, Alexa)
We moved IM2 in pitch to correct for the 60urad deviation that Kiwamu and Keita saw on Friday (alog 15081). Originally, IM2 P, Y = 17000, 5154 with M1_DAMP P, Y = 580, -51. This was adjusted to IM2 P, Y = 19200, 5154 with M1_DAMP_ P,Y = 637, -45.
We then repeated an IM4 scan on PR2. The new good alignment values are: IM4 P, Y = 6670.5, -2735.0
The scan procedure:
We moved IM4 in pitch until we saw the beam on the PR2 baffle. This allowed us to center the beam in yaw; we found that the good center position in yaw was -881.8 -- this was consistent for both top and bottom of the baffle. Then we found the pitch values for which the beam was just barely clipping the baffle:
| IM4 Pitch | IM4 Yaw | |
| Barely Top of PR2 Baffle | -24329.5 ± 2000 | -881.8 |
| Barely Bottom of PR2 Baffle | 37670.5 ± 1000 | -881.8 |
This average gave us the pitch position of 6670.5.
It turned out that yaw was bit more tricky. For whatever reason, the "barely clipping" procedure in yaw did not work; it gave us a center value of -3881. So instead we looked at the PR3 camera (with ITMs very misaligned), and determined when the beam disppeared in yaw:
| IM4 Pitch | IM4 Yaw | |
| Left on PR2 baffle, No beam on PR3 | 6670.5 | 6418.2 ± 100 |
| Right on PR2 baffle, No beam on PR3 | 6670.5 | -11681.8 ± 500 |
This difference amounted to 18,100 counts. We then looked at the PR2 baffle lower left and lower right beam positions, and found that this yaw seperation for the PR2 baffle diameter made sense.
As noted in Keita's alog 15063, the diameter of the baffle is 65.4mm, and the beam must be aligned to 26mm from the right edge (or equivalently 6.7mm from the center). So we used
yaw = center + radius in counts/ radius in mm * distance from center
yaw = -881.8 + (6.7 mm / 32.7 mm) * (-9050) = -2735.0
Keita pointed out to me that as we move the beam in yaw to clip on the left side of the PR2 baffle we will actually first see a back reflected beam from PR2. This probably explains why our yaw measurements for the "barely clipping" scheme was incorrect; we were probably measuring the back reflected beam from PR2 and not the beam from IM4.