Returned laser power to 2.4W, see alog 28931. Jenne set the guardian LASER_PWR node to 2.0 W. Note, the PSL rotation stage is operational and not locked out.
Krishna
The low-frequency (<0.1 Hz) noise in c-BRS looked much higher (~10X) than normal and we also noticed that the frequency and Q of the system were lower than that measured at UW. We suspected that the flexures suspending the beam-balance might have been damaged. Therefore, today I replaced them with spares that are fairly close to the original ones in size.
As a consequence of the flexure replacement, the mass distribution of the beam-balance has changed, hence the 'd' value is likely to be much larger than the previous value (~ 3 micrometers). The balance has currently been tuned to ~50 mHz frequency, which is close to the original resonance frequency. As is normal after a new flexure replacement, the mean angular position is drifting in one direction and will likely settle in 1-2 days.
If the low-frequency noise improves, I will likley measure a tilt transfer function tomorrow and try to improve the 'd' value, if needed.
ECR E1600230-v1
WP 6053
We analyzed the transfer function through the ETM ESD Driver before and after the capacitor and TVS were applied (see ECR). Using the Dynamic Signal Analyzer (SR785) set to sweep from 1kHz to 100kHz at 1000mV, the driver performs as expected when the waveform is applied to the PI input. I have attached a plot of the transfer function displaying modified HV, modified LV, and pre-mod HV values.
For future reference, this transfer function was taken from the differential PI input (pins 1/9 or 2/10 of the DB15 connector on the bottom of pg 1 in D1500016) on the front of the chassis to the BNC output inside the chassis itself (P5, P6, P9, or P10 in the middle of pg 1 in D1500016). The AC gain of this path is nominally 2.0, or +6 dB (G = 1 + R28/R30 on pg 6 of D1500016), but what mark shows here is that the gain changes by ~2 dB when the high voltage path is engaged. Also, the capacitor is 1 [nF] as quoted from the ECR. However, given the components surrounding this cap, I can't really figure out why the pole frequency is at 10 kHz. The input impedance to the relay (pg 8 of D1500016) is 200 [Ohm] from the summing node (pg 9 of D1500016). Thus, I would guess that the pole frequency would be at 1/(2 * pi * 200 [Ohm] * 1e-9 [F]) = 0.79 [MHz], not 10 [kHz]. One would need a resistance of ~15 [kOhm] to bring the pole frequency down to 1/(2 * pi * 1.5e4 [Ohm] * 1e-9 [F]) = 10.6 [kHz]. Because the pole frequency doesn't change, regardless of the relay state, it implies some other resistance to ground some where... Eh well. Measurements don't lie -- 10 [kHz] it is!
Checking/adjusting RGA temps
SInce the ETMs were available, I carefully tuned the PUM to TOP mas offloading gain for PIT and YAW. To do this, I drove the PUM at 0.1Hz with 20000cts on the L2_LOCK_[P/Y]_EXC, and set the gain on the TOP mass to exactly cancel the signal in the optical lever.
For YAW this can easily be done with sub-percent precision. The PIT TOP/PUM ratio features a lag filter with a complex pole zero douple-pair at 0.52Hz and 0.56Hz, which can be seen in the QUAD model. I designed a lead filter with those frequencies, but Qs low enough to match the phase at 0.1Hz exactly. The corresponding lead filter is in the M0_LOCK_P FM7 module:
zpk([0.325+i*0.405925;0.325-i*0.405925],[0.349999+i*0.437149;0.349999-i*0.437149],0.999999,"n")
The regquired gains in the M0_LOCK filter modules were:
ETMX PIT 898 *1e-6
ETMX YAW 1428.7 *1e-6
ETMY PIT 1294 *1e-6
ETMY YAW 1650 *1e-6
I put gain of 898, 1428.7, 1294 and 1650 into the M0_LOCK FM6 modules. By selecting FM4, FM5, FM6 (and FM7 for PIT) this implements a xross-over at exactly 0.1Hz. (pictues).
The same has to be done for the ITMs, and the guardian has to be updated to use those filters.
Also set the PUM to TOP cross-over to 0.1Hz for the ITMs, following the same procedure as for the ETMs. The gains were tweaked in the OFFLOADED configuration. The required gains were:
ITMX PIT 1147 *1e-6
ITMX YAW 1547 *1e-6
ITMY PIT 1155 *1e-6
ITMY YAW 1573 *1e-6
I also moved the gain filters to FM3 (removing the old +10dB filter), so it can be switched before the integrator. This was done for all 4 test masses, pit and yaw. With these filters, the settings shown in the attached screen shot result in a 0.1Hz x-over.
The guardian was updated to set this x-over just before engaging the soft loops. I havent switched the guardian to use the offloaded design for the ITMs though.
Title: 08/08/2016, Day Shift 15:00 – 23:00 (08:00 –16:00) All times in UTC (PT) State of H1: IFO is unlocked. HAM6 Vent Commissioning: Commissioners are commissioning as HAM6/IFO condition allow. Outgoing Operator: N/A Activity Log: All Times in UTC (PT) 13:55 (06:55) Chris S – Going to End-X to check wind fence 14:30 (07:30) Chris S – Back from End-X 15:00 (08:00) Start of shift 16:08 (09:08) Filiberto & Ed – In LVEA to prep for power and cabling work at HAM4 16:15 (09:15) Enable the Rotational Stage for Koji – Needed 10W of laser power for alignment 16:32 (09:32) Koji & TJ – Going to HAM6 16:36 (09:36) Betsy & Calum – Going to HAM6 16:38 (09:38) Hugh – Going to End-Y 16:40 (09:40) Filiberto & Ed – Out of LVEA 16:41 (09:41) Kyle – Going to End-Y 16:55 (09:55) Richard – Going to HAM6 17:01 (10:01) Hugh – Back from End-Y 17:08 (10:08) Richard – Out of LVEA 17:11 (10:11) Gerardo – Staging for Ion Pump work at GV3 17:16 (10:16) Jonathan – Going to H2 Enclosure to reboot computer on test stand 17:22 (10:22) Chandra & Gerardo – Going to GV3 to change Ion Pump (WP #6064) 17:28 (10:28) Kyle – Back from back from End-Y 17:20 (10:20) Jonathan – Out of H2 Enclosure 17:45 (10:45) Chandra & Gerardo – Out of LVEA 18:14 (11:14) Jim W & Ian – Going into LVEA to look at HAM6 18:16 (11:16) Kyle – Going into LVEA to look for controllers 18:50 (11:50) Richard – Going to HAM6 19:00 (12:00) Filiberto – Shutter controller work at HAM6 (WP #6065) 19:02 (12:02) Richard – Out of LVEA 19:07 (12:07) Koji, TJ, & Betsy – Out of the LVEA 19:31 (12:31) Krishna – Going into the LVEA (Biergarten) to work on BRS 20:07 (13:07) Chris – Going to Mid-X Fan room to change filters 20:08 (13:08) Richard – Going to HAM6 20:15 (13:15) Richard – Out of the LVEA 20:15 (13:15) Koji, TJ, Betsy – Going to HAM6 20:18 (13:18) Gerardo – Going into LVEA to move AUX cart 20:20 (13:20) Chandra – Going into LVEA to the measure piping for annulus pump 20:38 (13:38) Richard & Filiberto – Out of the LVEA 20:53 (13:53) Chris – Leaving Mid-X – Going to Mid-Y 21:02 (14:04) Kyle – Going to the Vertex RGA 21:07 (14:07) Filiberto – Going into LVEA for shutter controller work (WP #6065) 21:14 (14:14) Richard – Going into LVEA 21: 25 (14:25) Richard – Out of LVEA 21:26 (14:26) Gerardo – Out of LVEA 21:33 (14:33) Richard – Going into the CER 21:37 (14:37) Richard – Out of the CER 21:45 (14:45) Chris – Back from Mid-Y 22:04 (15:04) Chandra – Going to Mid-Y to fill CP3 22:14 (15:14) Ed – Going to Mid-X to look for a power supply 22:36 (15:36) Ed – Finished at Mid-X – Coming back to CS 22:56 (15:56) Chandra – Going into the LVEA to make measurements 22:57 (15:57) Krishna – Out of the LVEA Title: 08/08/2016, Day Shift 15:00 – 23:00 (08:00 – 16:00) All times in UTC (PT) Support: Cheryl Incoming Operator: N/A Shift Detail Summary: IFO is unlocked due to HAM6 vent for OMC repairs. Koji requested 10W of PSL power. Unlocked and re-enabled the Rotational Stage. Cheryl checked and aligned IMs. OMC alignment and HAM6 closeout work continues.
3:10 pm local Took 39 seconds to manually overfill CP3 with 1/2 turn open on LLCV bypass valve and bypass exhaust valve open.
Peter pointed out to me that the L2_LOCK filter bank for ETMX had FM8 (EvanR) engaged for both pitch and yaw, while for the other 3 test masses it was FM3 (EvanBR). All 4 test masses should be the same, so I've fixed ETMX and accepted it in SDF so that it'll come back correctly upon reboots. It looks like we've had the wrong filters engaged for ETMX since July 5th. I didn't check the ITMs, but ETMY has been correct since before July 5th.
Recall that we have the option between roll-only or both bounce and roll notches so that we could try running with the roll-only filters, which would give us more phase in the ASC loops so that we could make harder cutoffs. However, we've pretty consistently found that we ring up the bounce modes if we don't have the notches on, so we (should) have been using the combo EvanBR filters for all test masses.
Also, for some reason the decimation filters for the OUT16s on all of the ETMX L2 LOCK filter banks were off, and have been off for more than 100 days (that's how long I looked back for the bounce / roll filters). Evan, Peter and I agree that there's no reason for them to be off, so we've turned them back on.
PSL: SysStat: All Green, except VB program offline Frontend Output power: 34.1W Frontend Watch: Green HPO Watch: Green PMC: Locked: 0 days, 1 hours, 56 minutes Reflected power: 25.0W Transmitted power: 128.7W Total Power: 154.3W ISS: Diffracted power: 2.8% Last saturation event: 0 days, 1 hours, 57 minutes FSS: Locked: 0 days, 1 hours, 57 minutes Trans PD: 4.802V
Koji requested 10W of laser power for HAM6 alignment work. Set Guardian LASER_PWR node to 10W and re-enabled the rotational stage.
Recall the rotation stage has been disabled since Monday Aug 1 at the start of the HAM6 vent -- see LHO aLOG 28786.
SEI: No Issues SUS: Model restarts. HAM6 Vent work ELE: Cabling in LVEA, working on binary I/O card for PSL PSL: No Issues. TCS needs ITMY to finalize replacement of RF Driver VAC: Replace Annulus Ion Pump at GV3. Replace gauge at HAM6 when OMC work is finished. The HAM6 doors will go on either late Monday or Tuesday morning. There will be a film crew on site Tuesday, Wednesday, and Thursday. Ops will start evening shifts when HAM6 work is finished. Did work permit review.
J. Kissel, E. Hall, E. Goetz I'm reconciling the SDF system for PCALY, and I've found a difference in the amplitude of the 331.9 Hz line. After speaking with Evan Hall, he had been commissioning with the line a month or so ago with an abnormally large amplitude of 30000 [ct] (see LHO aLOG 28702), and accidentally left it in place. Since then, someone had blindly accepted this value in the SDF system. I've now reverted it to the O1 amplitude of 2900 [ct] (see e.g. LHO aLOG 27981). For future reference, all calibration lines that are on and present in the system: Channel Names _FREQ (Hz) _SINGAIN (ct) H1:CAL-PCALY_PCALOSC1_OSC 36.7 125 O1-scheme kappa_TST / kappa_PU H1:CAL-PCALY_PCALOSC2_OSC 331.9 2900 O1-scheme kappa_C / f_CC H1:CAL-PCALY_PCALOSC3_OSC 1083.7 15000 high-frequency calibration check ("bonus" line) H1:CAL-PCALY_PCALOSC1_OSC 3501.3 39322 high-frequency sensing function characterization ("mobile" line) _FREQ (Hz) _CLKGAIN (ct) H1:SUS-ETMY_L1_CAL_LINE 33.7 11 O2-scheme synched oscillator for kappa_U H1:SUS-ETMY_L2_CAL_LINE 34.7 1.1 O2-scheme synched oscillator for kappa_P H1:SUS-ETMY_L3_CAL_LINE 35.3 0.11 O2-scheme synched oscillator for kappa_T H1:SUS-ETMY_LKIN_P_OSC 35.9 0.11 O1-scheme kappa_TST / kappa_PU
Surveyed all viewports at LVEA, EX, EY. Several viewport lexan housings in LVEA are missing tabs. FRS report filed. Vacuum group will order more tabs from machine shop and install these.
Results of degassing PT170 & PT180 nude ion gauges in corner station are attached. Total pressure reading dropped slightly. Note: the corner was/is currently isolated from two cryopumps with GV 5 & 7 closed.
VBOB bake good, Corner Station vent/purge air supply normal for current conditions of 38F chilled water supply and 1/8th turn closed (from nominal 1/4 turn open) manual coolant valve (1 of 2 - not the after cooler valve), 1st STAGE AIR DISCHARGE 296F 2ND STAGE AIR SUCTION 82F 2ND STAGE AIR DISCHARGE 280F LUBE OIL 126F Did not measure dew point at HAM6 but observed drying tower switching. No alarms. Y-end RGA bake good > 160C everywhere on RGA side and tapering off to 70C @ the turbo inlet and the 4.5"-10" CFF BSC6 interface, 1610 hrs. local -> Leaving site now.
Thanks for checking on the purge air, Kyle.
1415 - 1425 hrs. local -> To and from Y-end checking RGA bake that was started Thursday morning (discovered that I don't have a WP for this! Will initiate one today and ask for forgiveness later - its easier than getting permission!) GV3 AIP died -> will address during the week. Will make comment to this entry when leaving site.
Added 3rd variac to Y-end RGA bake so as to enable control of Cal-Gas bottle zone independent of other parallel heated zones. Also added a fan for the scroll pump. VBOB bake good. Corner Station vent/purge air supply also good. Temps, pressures same as yesterday but dew point a little higher at -30C. 1745 hrs. local -> Leaving site now.
Ansel and I put the end station CPS timing fan outs on separate +/-18V power this evening in hopes of eliminating the comb of odd harmonics of 1 Hz in DARM. A similar comb had been evident in the magnetometer that I set up at the EY ESD to look for blip glitches, and it went away when we powered the fan out with a separate supply. We think that this is because the magnetometer was detecting ripple in the field radiated from the +/-18V connector on the low V ESD drive and that we eliminated the ripple on ESD power by powering the CPS timing fan out on a separate supply. For this reason we varied from the work permit and didnt put them in a different rack. Ansel will fill in details of the studies he did that made us think that this is the source of the comb (especially if it really does go away in DARM), but we think that the comb isn’t GPS synched because it is driven by a clock on the PSoC board of the CPS timing fan out. Isolation of BSCs 9 and 10 has been restored to nominal.
Ansel Neunzert, Robert Schofield
This shouldn't be right. The PSoC board is supposedly clocked by half of the provided 71 MHz signal. However, looking at the photos on E1400155 I see that the 2 crystal oscillators of the development are still soldered in. Please tell me this is not true for the units installed in the field.
Tagging SEI and CDS.
Our understanding of the electronics is based on the same DCC document/photos that Daniel linked to.
Some background info on what led us here: the comb was first reported in May by Brynley Pearlstone (alog), and again by Keith Riles in his ER9 narrow lines report (alog). Per Keith's report, the spacing is 1.999951-Hz, visible on approximate odd-integer-Hz frequencies. Robert and I looked back in older data for its appearance, and isolated the date range between February 26 and April 2, but there was not enough good DARM data in that window to track it further. Turning to magnetometer data, we found the comb in a channel at EX (H1:PEM-EX_MAG_VEA_FLOOR_X_DQ), and tracked its appearance down to March 14th using data from that channel (with help from one of Keith's students, Eilam Morag, who has written code for tracking the strength of known combs). We initially suspected the computer system restart on that date, but have not found evidence to support this hypothesis by examining data around subsequent restarts. As a second guess, we looked into the changes to the CPS timing system made on that date (alog) (both end stations). Coincidentally, Robert had placed a magnetometer in the CPS rack at EY to search for blip glitches, and this magnetometer showed the comb strongly, which motivated us to look into the CPS timing fan out.
In the PSoC software, you can select where its clock comes from. They are clocked from 1/2 the site 71MHz. The oscillators are not removed from the board, just de-selected from the clock menu in software.
