I unlocked the PMC and swept over C1:PSL-PMC_RAMP's full range a couple of times this morning. The PMC should now be relocked and returned
Component Schematic Actual
--------- --------- ------
C140 10u open
C144 10u open
C149 open a gray Cap. value unknown
C141 10u open
C145 10u open
R97 1.58K 0
R99 open 1130
R103 open 1130
R100 open 0
R104 100 1130
R98 1.58K open
R109 367 365
Your PZT is broken.
Alberto and Koji
o We worked for the abs length measurement setup on Thursday night.
o At the last of the work Koji left the 40m lab at 2AM. "Last autoalignment" was restored. The flipper for the
inj beam was down. The shutter for the NPRO was closed.
o The alignment of the injection beam (NPRO) was re-adjusted.
o The laser crystal temp (LT) of the NPRO was scanned.
o After a long struggle the beat was found at about LT=61deg(!). I think this is almost at the maximum temp
for the NPRO. Note that this is not the diode temp, and therefore it will not damage the laser as far as the
TEC for the crystal works.
o Only the X arm was aligned.
o The alignment of the injection beam was adjusted such that the beating amplitude got maximum.
o At the faraday of the NPRO, we had 2.4V_DC and 1.8V_DC with and without the inj beam, respectively. The
beating amplitude was 200mVpp (at around 2.4V).
o With a simple calculation, the mode overlapping of tghe injection beam is only 0.0023. Ahhh. It is too weak.
In the modematching or something must be wrong.
o The position of the mode matching lens was tweaked a little. It did not help to increase the beat ampitude.
Even worse. (The lens was restored and the values above was obatined with the latest setting.)
o Then tried to build a PLL. It locks easily.
- Put the beat signal into the mixer RF input.
- Connect 10dBm @1MHz-10MHz from the marconi oscillator to the LO input. The supposed nominal LO level was
not checked so far. Just used 10dBm.
- The IF output was connected to an SR560 with 10Hz LPF (6dB/oct) with G=500 or so.We don't need to care
about the sign.
- The output of the SR560 was connected to FAST PZT input of the NPRO.
o The problem was that there was strong intermodulations because of 33MHz. No LPFwas used before the mixer.
Because of this spourious modulations, the PLL servo locks at the local zero crossings. These will be solved
o Eventually left the 40m lab at 2AM. "Last autoalignment" was restored. The flipper for the inj beam was
down. The shutter for the NPRO was closed.
1) Continue mode matching into the PMC. Its transmission now is around the same as the
2) Put a UHV foil covered lead brick onto the PMC to quiet it down.
3) Characterize the PMC loop and retune the body notch for the new body.
4) Tweak the MZ alignment to minimize the RFAM. We can use StochMon to do this as
long as we have the MC WFS turned off or we can put in a flipper to take the
beam before the MC and send it to the StochMon RFPD.
5) Re-align onto the ISS.
6) Install irises around the periscope for the beam. The old iris there is way off.
7) Fix PSL ANG and center both POS and ANG.