The ISS ref signal was changed from -2.01 V to -2.09 V which in turn changed the refracted power from 15% to about 5 %.
Leonid.Prokhorov, Jeffrey.Kissel Results of OPLEV charge measurements (June, 24 - July, 06): Charge at the ETMX and ETMY is less then +/-10V. ETMY seems slightly negatively charged (about -3..-5V). We haven't see charge growing or significant changing of charge at ETMs over this time. Plots in attachment: a) ETMX, ETMY - all measured charge data points (include today's measurements) b) ETMX, ETMY mean value of charge for each the day and it's standard deviation + and weighted mean and weighted variance of measured charge for each day.
Sheila, Evan
The in-vac REFL9 phase shifter is now controllable from the control room.
The REFLAIR9 phase shifter already had a dsub cable running to the Beckhoff concentrator (cable 68, running into concentrator 3), but the REFL9 shifter did not. So we moved this cable over so that it controls the REFL9 shifter. We also moved the cable over by one slot on the concentrator. We flipped control of the REFL9 shifter from internal to external, and then moved the digital delay slider to match the delay given by the toggle switches (23.4 ns). So the LSC-REFL_A_RF9_PHASE channels now control the delay.
Then we locked PRX, drove a line in the PRM, and then verified that the delay shifting works from the control room.
The variable pitch actuators on all of the supply fans in each of the out buildings were exercised this afternoon. S.F. 01 at Mid X and S.F. 02 at Mid Y were found to be faulty. We are only operating 1 fan at each mid station so these can be repaired with no impact to the cooling of the buildings. I will look into ordering parts tomorrow.
~0930 hrs. local -> Valved-in HAM6 ion pump -> Experimented with MidiVac vs. LPC controllers -> Leaving on LPC for now -> Will valve-out HAM6 turbo tomorrow
The vacuum gauges for the NEG pumps were added to the EtherCAT system. They are now available in EPICS (but not dataviewer until tomorrows DAQ reboot).
All times in UTC.
15:00 Morning Checklist:
15:45 Leo doing Charge measurements
15:57 Kyle out to HAM6 to disconnect uneccesary equipment.
16:26 Sudarshan out to LVEA to set up ISS second loop measurement. (called back due to Jim taking measurements on IMCs
16:33 Fil to EX to take meauerements for P-Cal cables.
16:50 ITMY RMS watchdog tripped. Reset.
16:53 Kyle back from HAM6
17:00 - 18:00 Luca's training class
18:15 Sudarsh and Kiwamu out to LVEA to set up ISS Second loop measurements
19:24 Leo finished doing charge measurements.
20:00-21:00 Luca's training class
20:36 Bubba and John to both end station mechanical rooms
21:21 Jordan and Katie to EX. PEM Install and Calibration.
22:30 Sudarsh and Kiwamu into LVEA.
It appears that this tripped at ~ 10:15PDT on July 3?
For the record, this is the L2/PUM analog coil driver RMS watchdog.
In this analysis we used 1 minute FFTs of H1:LSC-DARM_IN1_DQ for derr.
Channels H1:CAL-PCALX_TX_PD_OUT_DQ, H1:CAL-PCALY_TX_PD_OUT_DQ and calibration factors from DCC T1500283 were used to calculate Xpcal.
The time delay of 125 us between Pcal and DARM signals (see LHO aLOG 19186) should cause phase delay of high frequency lines of about 24.3 degrees, but not over 140 degrees as we saw in our analysis. The question, why phases of high frequency lines are rotated by 140 degrees compared to phases of low frequency lines, needs to be studied.
Changes in actuation function, A, can confuse results produces by this method. This issue can be avoided by applying a time dependent A in calculation of Cifo.
An estimation of how much changes in CC pole frequency can increase uncertainty in calculation of external length strain need to be studied.
We plan to repeat this analysis with LLO data.
Picking up where Arnaud left off nearly 2 weeks ago, alog 19208 post vent, I am looking at the health of the TMSX suspension. Basically, we reinvented what he stated - the TMSX LF and RT BOSEMs are less sensitive than they were "before". The TFs show a DC offset from the Model and the TFs taken a year ago. We're not sure why this is - Kiwamu suggests that a change in the stiffness of the suspension made during the June cable strain relieving likely would have caused the resonance peaks to shift as well as the DC offset... We don't think this DC shift is too serious - the loop gain in V and P need to be retuned.
I can drive the TMSX with PIT alignment bias and see the Left and Right (suspect) BOSEMs respond, so they are not "out of range" and are actuating.
I reran the TMSX TFS for PIT and VERT - Both look healthy to me, so whatever bad measurement was posted in the middle of the 19208 alog is still gone.
I agree with Betsy -- a change in stiffness would only affect the magnitude of the transfer function at low-frequencies. An overall scale factor discrepancy like what is shown here is typically a problem with an electronics gain being different (say, if a satellite pre-amp's circuits have much less gain than before), or an incorrect digital gain (say, if the EUL2OSEM / OSEM2EUL matrices were systematically incorrect). It might be that the diodes have a new, worse, open light current, and what is being used for digital compensation / normalization is now in correct. It would be difficult to believe / quite the coincidence that would a problem from *both* LF and RT at the same time. Recall that this is FRS Ticket #3246. ------ For reference, I also quote Keita who had replied on this over a small-email-list: "" Seems like TMSX RT and LF are bigger than before by maybe 5000 counts or so, which I didn't catch when we came out of chamber. We added small masses (strain relief parts) to TMS, so this makes sense qualitatively. These numbers were already big-ish before vent in a retrospect, and RT is now about 4000 counts away from the open value which is supposed to be -2*H1:SUS-TMSX_M1_OSEMINF_RT_OFFSET~26000 cts. No idea if 4000 counts is too small a margine there, nor if the BOSEM height is the cause of the poor measurement results. Anyway, my questions are, 1. Were the suspension bias sliders on or off during the measurement? If not, measure with nominal offset even though we don't know the right alignment for now. 2. Is the S/N of the PIT sensing considerably smaller than before? If it is, TMS should be noisier than before due to noisier PIT damping, which in principle compromise ASC performance for ITMs (DSOFT, CSOFT). Regardless of the answers, my gut feeling is that it's possible to run H1 without fixing the BOSEM height for O1 (unless TMSX is shaking too much due to this and the IFO wouldn't lock). ""
The PIT and VERT TFs that I ran this morning were with the bias sliders enabled.
VAC : pumping going fine. Y-arm to be opened tomorrow. X-Arm on Wednesday. Sloww process to valve-in new getter type pumps.
SUS: FE model changes to be done tomorrow. Betsy picking pu TMS investigations from two weeks ago.
SEI: Evals of FF. HAM6 HEPI Still locked. FE models update for Tues / sensor correction.
CDS: P-Cal cabling at both end stations. Richard/Fil will have a look at the TMS PDs. GPS cabling scheduled for rooftop on Tues.
COMM: Continued working on MICH FREEZE (silmultaneous DRMI locking)
FAC: X-Arm cleaning complete, Y-Arm cleaning ton commense tomorrow. Extra person, Rodney, added to cre to expedite.
1440 hrs. local -> In and out of X-end VEA, 1450 hrs. local -> In and out of LVEA and 1500 hrs. local -> In and out of Y-end VEA. 1515 hrs. local -> Kyle leaving site now.
Previously we have seen that moving to in-vac REFL9I for control of CARM has led to worse DARM noise at high frequencies. So as a first step in diagnosing the issue, I wanted to check the phasing of REFL9.
With DRMI locked, I drove a line in PRCL at 212 Hz and then adjusted the in-vac REFL9 LO phase shifter in order to minimize the appearance of the line in REFL9Q. (Since we don't have CARM at the moment, PRCL is the next best thing. Of course, the phasing should be rechecked for CARM once we are back to full locking.)
Originally the phase shifter had 16+4+1/4+1/8+1/16 = 20.44 ns delay, with REFL9Q/REFL9I = 0.15/0.85 = 0.18 at 212 Hz. Now the phase shifter has 26+4+2+1+1/4+1/8 = 23.38 ns delay, with REFL9Q/REFL9I = 0.005/1.08 = 0.008.
Nic, Evan, Jenne We tried looking at the efficacy of MICH freeze with DRMI today. First, we looked at the MICH fringe velocity in Michelson-only: With the MICH freeze engaged, the fringe velocity seems to slow down by a factor of about 2 versus without the freeze. Then we aligned the DRMI and tried to get some locking statistics (length of time waiting for lock) with the freeze on vs. off, but we aren't really getting any locks at all. We waited more than 15 minutes without a lock with the freeze off, so we went to trying with the freeze engaged. With MICH freeze engaged, we had 2 wait times of 2 or 3 minutes, but all other times have been more than 15 minutes. (We tried changing trigger threshold settings a few times, which is what defined the ends of these 15 minute wait stretches). So far, it's not clear to us whether the MICH freeze is having a significant effect at all. We think we'll try again later.
Nic, Jenne, Evan
In spite of the bad POPAIR situation, we were able to get DRMI to lock by increasing the whitening gain of POP18 (from 12 dB to 45 dB), and by lowering the trigger thresholds for MICH by a factor of 10, and SRCL by a factor of 5.
After DRMI locked, we were able to optimize the buildups of POP18 and AS90, mostly by moving PR3 positive in pitch, and then compensating by moving PR2 negative in yaw. In this way we increased the buildup of POP18 by a factor of 45. (We then undid the extra analog whitening gain.) So this seems to support the idea that our issues are caused (at least partially) by misalignment of the power recycling cavity.
We went onto the table and again tried to resteer onto POPAIR_B, but we got only 10 % more power on the PD. POP18 is now at about 6 ct (normalized), whereas we expect about 300 ct for DRMI without arms. So there is still a missing factor of 50 somewhere.
We measured the OLTFs of PRCL, MICH, and SRCL, and they seem fine. So the DRMI LSC seems healthy as far as we can tell; there's just some problem with the POP path.
(evan jenne nic)
Evan said that the Q of the BS butterfly hadn’t yet been measured.
We let the system alone for 10 minutes in DRMI and analyzed the ringdown. The biggest SNR was in the PRCL error signal.
The resonance frequency is 2449Hz, the Q factor is . This means a time constant of 12 minutes.
Ringdown with fit is atached.
(script attached)
