Has been for about 20 min.

Per work permit 4479.

Output power is ~ 28 W (should be 30 W)
Watchdog is active
'check Xtal chiller' status is red

PMC
PMC has been locked for 19 hours
Reflected power is 11% of transmitted power (should be 10% or less)

FSS
Reference cavity has been locked for 10 hours
Trans PD threshold is set to .5 V (should be at least .9 V)

ISS
Last ISS saturation event was 10 hours ago
Diffracted power is about 4% (should be 10%)

(Jax, Keita)

Today Keita and I marked out the rough position of the back corners of ISCTEY at BSC10 to facilitate its move to its final location next to the BSC. The nominal position of the table is 18" away from the ALS viewport in the -X direction, with the left edge of the table 22" in the +Y direction from the ALS viewport (lower left viewport on BSC10). The numbers are given in inches because none of the measuring tapes we found had metric markings. Here is the information and calculations used to determine this position. 

The beam angles from the TMS were taken from sheet 7 of D0902163. Since this is the layout for EX, we need to consider the mirror image of this layout. Therefore, the horizontal angle is not in the -X direction, but in the -Y direction. The horizontal angle phi is determined from the alignment angles as outlined in the attached pdf. 

For the ALS beam angle of 12.4 degrees, the horizontal shift per meter is 22cm. The table is placed approximately half a meter from the viewport, corresponding to a shift of 11 cm/~4.25". The center of the table opening for the ALS beam is 27.5" from the edge of the table enclosure, so add this displacement to 27.5" to determine the shift in position. This gives our layout position of 22" in the +Y direction from the ALS viewport.

The only question we have remaining is the position of the table in the X direction. We have laid out and calculated a position consistent with the table installed at EX, but there is some possibility the mode-matching on the table was set with a distance of 1 m in mind. If the table has to come back half a meter, this would add 11 cm to the horizontal displacement. The clearance on either side of the ALS table after moving the E-module will be 9" (ref. Bubba), so if the position has to be modified to address this, the additional 11 cm/4.25" will be attainable with our available space. Alternatively, the mode-matching telescope on the table can be adjusted to be optimal for this position, which is more consistent with the table as installed at EX. 

(Edited because the equations were exported as PDFs instead of PNGs and didn't show up... and AGAIN because despite showing up just fine in the previews, the equations refuse to show up. Attached the work as a pdf.)

Sometime between leaving the cartridge test stand and yesterday inside of BSC10, the optics in the suspension got really dirty.  The barrels of the ETM test mass, ERM optic, and PUM have accumulated alot of particulate.  I wiped these clean just prior to welding in Jan and recall them looking much better than they do in the pictures below when they were hanging on the test stand.  So, between the last bit of cartridge work, the cartridge flight and the in-chamber work over the last week lots of particulate has swirled around the in-vac hardware (about a 2 week duration).  Here's the sequence of cleaning in case Calum wants to know:

On test stand, just prior to flight:

- I wiped and vacuumed SUS, bagged both SUS and TMS

- Hugh wiped all of the ISI above, then bagged ISI

Cartridge flight Feb 24th

~2 days after in-chamber I wiped entire floor and viewport surfaces of BSC10 chamber, I did NOT inspect optics

- cabling, TMS payloading, SEI float/balance

- yesterday, I see this gross particulate accumulation, some on the suspension structure too, harder to see since it's metal surfaces though

- I wipe the entire floor of chamber again

More cleaning to follow, obviously.

Alexa, Daniel, Sheila

RED TEAM: We are exciting ETMX, ITMY Pit and Yaw over night.

I have excited ETMX, ITMX Pit and Yaw, L2 test filters at various frequencies. The oplevs move from around .2urad to .5urad. In this configuration the green lock transmission ranges from 760 counts to 400 counts. Increasing the drive caused the arm to lose lock (and we assumed Keita wanted to make his measurement with the arm locked), and caused ITMX suspension to trip. Hopefully, this set up is enough for Keita's measurement. The start time was around: 8:34:52 UTC time. The excitations are being run by four awggui's on opsws7. I have attached the awggui configuration and a picture of the oplev motion on dataviewer.

We had a lot of trouble early in the evening isolating ETMX, we kept tripping the watchdog on stage 2.  We tried reseting the CPS offsets, and eventually were able to get it to isolate with Tcrappy and level 2 controllers, but the motion was rather large (~ten fringes per second).  We left stage 2 with damping only. 

Alexa, Daniel, Sheila

We normalized the refl PDH error signal, and saw that we can stay in the linear range of this signal with only ALS COMM locked. 

We first normalized LSC-X_TR_A_LF by adding a gain of 0.000154 so that the tranmission peak is at roughly 1.  We set LSC-REFLBIAS to  REFL_A_RF9_I over the transmitted power (LSC-X_TR_A_LF).  The first screen shot is the PDH, the transmitted power, and the normalized error signal as we move the COMM VCO set frequency.  In the red trace we moved the frequency by 2kHz; meanwhile, in the blue trace we moved half as fast over 1kHz.  We used Alexa's equation from alog 7054  to roughly calibrate the signal: 80Hz cavity pole/150 counts pp of the PDH signal=0.533Hz/count.

We put this gain into the REFL_BIAS filter, we will do a more carefull calculation in the morning. With this calibrated error signal we were able to measure an out of loop spectrum of the noise between the arm cavity and the PSL.  Attached are some of the spectra that we took. In the top panel the green trace is a reference with the cleanroom over HAM1 on, in the red trace we turned the cleanroom off and Alexa tried to tune up the arm cavity alignment by maximizing the green transmitted power.  This realingment clearly helped at low frequecies, and reduced the coherence with the ETMX PIT oplev. 

The RMS we measured is completely dominated by low frequency noise that changed, probably because the alignment was drifting.  The RMS down to 0.1 Hz varied from 30Hz-70Hz, we also measured an RMS of 58Hz down to 0.01 Hz.

We saw coherence with the end station PDH reflected signal above 1kHz,  coherence with the PIT oplevs (mostly ETMX, which currently has level 2 controlers on Stage 1 and damping only on stage 2) around the PIT resonances (0.4-0.5 Hz), and coherence with YAW OpLevs from 0.04-0.5 Hz.  We also looked for coherence with some of Robert's PEM sensors, we have coherence from the periscope on ISCT1 from about 50-100Hz, as we kind of expected.

Tonight the noise is much worse than it was on saturday, the transmitted power was not stable at all over time.  This might be because we don't have as good of an alignment, or be because the arm cavity motion is larger because of the problems with ETMX ISI.  We also measured the spectrum with higher and lower gains in the COMM board, higher gain did not seem to help, which is different from the situation on saturday alog 10439 . 

We completed the changes in the lsc model to include the ALS-C_REFL_DC_BIAS path. It is split off the input matrix and now has power normalization, an extra LSC filter module (LSC-REFL_BIAS), and triggers. It bypasses the output matrix and directly links to the ALS filter module which is outputed to the DAC. The DAC channel is available at the DB9 breakout panel at the ISC-R4 rack. It is intended to be wired into the CM summing node. Currently, it is wired to the second input of the common mode board. Medm screens have been updated to add the extra matrix row where needed. The new filter modules are only available from the ALS_CORNER overview screen. Model and medm screens have been submitted to svn.

PLC3 on h1ecatx1 can't be activated and run using the install srcipts.  If you open PLC control and try to login it asks you which run time system to use, if you select run time 3 it can login and seems to be running OK.

[Ed, Yuta, Stefan, Arnaud, Sebastien, Jeff, Evan]

Temperature loop

On Sunday, Stefan helped me get a stable temperature loop going for the auxiliary laser PLL. The lasers now stay frequency-locked for about 5 minutes. We take the fast control signal, feed it into an SR560 for gain/rolloff control, then attenuate a bunch, and feed it into another SR560 which sums this signal with a trimpot-controlled DC offset signal. This signal then goes into the slow control of the laser. I suspect the short lock time is due to the fact that the SR560 has no integrating feature; right now I've just set it to have a DC gain; the pole of the temperature loop is set by the thermal pole of the laser. A diagram of the loop topology will be uploaded soon.

PRMI FSR sensing: no success

On Monday, the EE shop made me a 60-ft BNC cable with LMR-195. I used this to take the raw RF signal from REFLAIR_B and bring it over to the IOT2R setup. This signal is demodulated using the PLL offset frequency as the LO, and the resulting DC trace is monitored on a scope.

This afternoon, Yuta and I stole time from the green team in order to lock PRMI and try to see if the demodulated REFLAIR_B signal would show any kind of error signal in response sto the PLL offset being swept across an FSR of the PRC. We swept from 58 MHz to 62 MHz, but did not see a clear DC response from this error signal; the DC was between -1 mV and 0 mV, with an rms noise of a few hundred millivolts. If the offset frequency was set to be near a harmonic of 9.1 MHz, the error signal would become dominated by the beat of the harmonic against the offset frequency (as one would expect).

Next, we tried looking at POPAIR_B_LF to see if we could see a DC power buildup as a function of PLL offset. We didn't see anything; the DC power fluctuated between 70 and 90 counts at all times, and showed no change in response to the PLL offset.

Addendum on PRMI Iocking

Yuta tried for some time this afternoon to get PRMI locked. The biggest stumbling block was that PRY showed no fringes. Eventually, with the help of Arnaud, Sebastien, and Jeff, it was realized that

1. ISI target values (e.g. H1:ISI-BS_ST1_CPS_RZ_TARGET) change after each CDS reboot; they must be corrected by hand. BS ISI stage 2 Rz was particularly bad.
2. Changing the signal blending from 'Start' to 'TCrappy' for BS ISI stage 1 and turning stage 2 off helps locking PRMI. When ISI settings were wrong, power recycling gain showed large fluctuations at ~0.5 Hz (presumably from the microseism), with a modulation depth of about 50%.