R. Short, J. Oberling, M. Nakano (remote)

This morning Masayuki ran an assessment of the JAC mode matching after our EOM swap yesterday and came up with new lens positions for the mobile JAC mode matching lenses (IO_MB_L1 and IO_MB_L2).  The result we were given:

SITE INSTRUCTION -- two-lens solution (IO_MB_L1 + IO_MB_L2):

move IO_MB_L1 by 2.0 mm DOWNSTREAM (toward JAC) (dz_L1 = +2.0 mm)

move IO_MB_L2 by 34.6 mm UPSTREAM (toward the PMC) (dz_L2 = -34.6 mm)

(decomposition: common -16.3 mm = waist position, differential +18.3 mm = waist size)

L1-L2 gap: 60 mm -> 23 mm

Moving IO_MB_L1 went smoothly with no change to the beam alignment.  However, we were not able to move IO_MB_L2 the full requested amount due to interference between the lens mounts.  Instead of the requested 23mm separation between the lenses, the best we could get was ~26.5 mm.  To get any better than this we would have to completely change the mounting setup for the lenses.  After moving IO_MB_L2 we had to yaw it a little to recover the beam alignment onto our irises.  While the irises looked good in the PSL enclosure, when we tried to lock JAC it wouldn't lock; Masayuki had to do some alignment tweaks to get the JAC to lock.  This isn't entirely surprising given that our alignment irises are several meters away from the JAC in HAM1, so what looks good on the irises isn't necessarily good enough to lock the cavity.  Once the cavity was locked, Masayuki began tuning things up and we left the enclosure.  He's running his mode matching assessment code now, so we'll see what the results show (preliminary report: "The mode matching seems better." -M. Nakano).