I've set up the script co2X_delayed_start.sh to turn on about 650mW of CO2 central heating on ITMX at 12:05AM. It will turn off after 4 hours.
Aidan. Alastair. Greg.
We started heating ITMX with the central heating beam while running the HWSX sensor. We observed the gradient field of the HWS sensor (created from the difference between before and after 1W of heat applied for 100-200s). The sharp edge of the heating pattern was clearly visible in the gradient field.
We iteratively adjusted the upper periscope mirror on TCS CO2X (PICO_F_3) to adjust the alignment to ITMX. As a roughly calibration we measured 42 mm of motion for 7000 counts applied to the picomotors, or with the signs included:
I'm not 100% confident that the calibration of the center of the optic is correct. However, the HWS gradient field displayed here is adjusted to the coordinates of the test mass using this morning's RH measurement.
Also, note that we're measuring the position of the CO2 laser beam using the transient thermal lens which provides a strong signal at the edge of the heating beam during the initial stages of heating. The measurements below do not represent the steady-state thermal lens which will look significantly different.
However, the bottom line is that the CO2X central heating beam that was not correctly aligned to the center of the test mass is not much closer to being aligned. We will continue to fine tune this tomorrow.
The plot below shows the iterative alignment of the CO2 heating beam. The first and second panels are the original alignment. The second panel is zoomed in around the HWS measurement. The green circle represents the edge of the test mass. The red circle represents the diameter of the TEM00 mode of the IFO. The blue arrows are the HWS gradient field. The strong arc visible in the bottom left corner is the edge of the CO2 heating beam thermal lens. The PICO motor counts for the upper periscope mirror are shown in the titles for the plots.
Aidan.
I upgraded the HWS code to v1.1.5 on H1HWSMSR. This change saves the centroid data as a MATLAB workspace with GPS time in the filename in the FRAMEARCHIVE directory.
Something about the installation on H1HWSMSR is preventing the centroid data being saved in the nominal GWF file format in v1.1.4 of the code, so the v1.1.5 addition is a work around until we fix that installation issue.
Aidan. Alastair.
Around 10:40AM Alastair and I were looking at the ITMX HWS EPICS channels (spherical power, prism, etc) and noticed them getting very noisy. After some discussion with people in the control room, it turned out that there were some white noise injections going into the ETMX suspension.
We started streaming the image from the HWSX camera to the control room - it's peak intensity was around 1500 counts. We misaligned ITMX by several hundred micro-radians, until the return probe beam disappeared from the HWSX stream. There was a residual beam in the image, with a peak intensity of around 300 counts, that was swinging around. We confirmed this was ETMX by changing the pitch of ETMX from 403 to 360 micro-radians and observing the residual beam disappear.
Once the IFO alignment is settled, we will likely need to adjust the HWS alignment so we don't get any return beams from the ETMs.
Alastair, Aidan.
We tracked down the source of the cross-coupling between the HWSY probe beam and the HWSX sensor. The offending beam was coming from the HWSY BS (we think). By blocking the Y-beam at various points we were able to figure out where it was coupling across the HWSX and we subsequently placed a dump in front of it before that point (between M8 and M9 in the Y-arm optical layout - see the attached photo).
One more thing, I checked the following configurations to look for any other stray beams:
Optical Lever Whitening Chassis Rack Locations and Chassis Locations and Current Binary Output Module Status at LHO: D.Cook 10/29/2014 Rack SUS H1-R1: Chassis cabled - Board 1- HAM 2 = No BOM installed Chassis cabled - Board 2- HAM 3 = No BOM installed Rack SUS H1-R2: Chassis cabled - Board 1- HAM 2 = No BOM installed Chassis cabled - Board 2- PR3 = BOM installed B1, B2, B4, B9, B10, B12, 17, B18, B20, B25, 26, B28 set HIGH (the rest set LOW) Rack SUS H1-R3: Chassis cabled - Board 1- HAM 5 = No BOM installed Board 2- SR3 = BOM installed B4, B12, B20, B28 set HIGH Rack SUS H1-R4: Chassis cabled - Board 1- HAM 4 = No BOM installed Chassis not cabled - Board 2- Empty Rack SUS H1-R5: Chassis cabled - Board 1- BSC 8 Pier (temp ?) = No BOM installed (jumpered connecter) Chassis cabled - Board 2- BS = BOM installed B1, B3, B4, B9, B11, B12, 17, B19, B20, B25, 27, B28 set HIGH (the rest set LOW) Rack SUS H1-R6: Chassis cabled - Board 1- ITMx = BOM installed B4, B5, B12, 13, B20, B21, B28, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty Rack SUS H1-R1 ETMy: Chassis cabled - Board 1- ETMy = BOM installed B4, B5, B12, 13, B20, B21, B28, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty Rack SUS H1-R1 ETMx: Chassis cabled - Board 1- ETMx = BOM installed B2, B3, B5, B10, B11, B13, B18, B19, B21, B26, B27, B29 set HIGH (the rest set LOW) Chassis not cabled - Board 2- Empty
This entry has several bugs making the data incorrect. A corrected status chart can be found in LHO aLOG 14749
08:55 Karen cleaning at mid and end Y 09:03 Ed reinstalling UIM driver for quad test stand 09:05 Hugh bringing HAM2 ISI down to make a safe.snap file 09:24 Gerardo and Alexa transitioning end Y to laser safe (WP 4923) 09:32 Alastair to install FLIR imaging camera on TCS Y table (WP 4924) ... not done, parts need to be made 09:45 Gerardo and Alexa done transitioning end Y to laser safe 10:03 Hugh taking HAM3 down to upgrade matrices and make a safe.snap file 10:12 Truck at gate here to pump septic tank 10:45 Hugh removing malfunctioning HEPI pressure sensor box at BSC2 10:47 Doug cataloguing the status of the switches on the optical lever whitening boards in the LVEA 11:02 Hugh done at BSC2 11:18 Travis moving suspension upper structure into clean room in West bay (heavy) 11:33 Travis done 12:08 Doug done 12:31 Betsy to West bay for 3IFO quad work 12:57 Doug cataloguing the status of the switches on the optical lever whitening boards at the end stations 13:26 Karen done cleaning at mid and end Y 13:48 Hugh to BSC2 to reinstall HEPI pressure sensor box 14:05 Hugh done at BSC2 14:38 Doug in LVEA recording locations of optical lever equipment 14:45 Delivery for Richard 14:45 Doug done
See the attached for some manipulated data.
There are now pressure signals coming from the End Station VEAs just before the BSCs fluid distribution manifolds. So the pressure before the actuators and the pressure just after the actuators (before and after the distribution manifolds.) See the first attachment--you can see that there is some 6psi pressure drop from the last transducer on the Pump Station Manifold to the Transducer just before the supply distribution manifold at the chamber. This is a distance of some 80 or 90 feet of 1" tube.
The idea is that the Actuators are meant to operate at a consistent pressure drop and having the sensors in the area of operation and where we have tighter temperature regulation would be a better thing. While these epics channels can be conditioned (smoothed, averaged,...) the second attachment shows how much noisier these raw signals would be to produce the differential pressure signal for the servo. I've subtracted the Return Pressure from the Supply to get the Differential; the vertical scales are the same for the two EX signals,and the same for the two EY signals. All plots are in PSI.
Why are they so much noisier? Let me see, maybe the 80 or 90 feet of cable? We do have an at chamber active signal amplifier, don't know the DCC off hand but later.
Anyway, I may be a little reluctant to switch HEPI to these signals. I don't think any one has complained about HEPI because we are running on the direct supply pressure rather than the differential.
As RichM pointed out to me, in the second plot, the lower traces of Output Pressure are in loop and the True Differential plotted above are out of loop. I would expect these situations to reverse whence the servo switches to the latter. Additioinally, the first plot which has the max & mins, show the overall noise on the three channels are really the same at the stations; there is certainly more noise on the EY sensors by something like a factor of 2. But you can see how much quieter the mean is on the servo'd channel.
So, I don't think there is sensor noise issue here to worry about.
Yeah, that's right HAM1. Safe.snap committed to SVN.
With the optical levers now well calibrated, we re-assessed the benefits/drawbacks of blending low on Stage 1 Z. In the plot attached, ETMX Stage 1 Z was in high blend (T750), while all others were in low blend mode. Data was taken this morning from 3am to 4am PT.
- The first plot attached shows that the ETMX optical lever pitch motion is four times higher than the other test masses (second line, third row). This vertical to pitch coupling justify the need for blending low on Stage 1 Z.
- The Yaw motion (second line, third row) shows that the low blends on Stage 1 Z amplify the Yaw motion by a factor of two, through the "Z to RZ coupling" problem that we are trying to solve.
- Just for info, the second attachment shows the Pitch to Pitch transfer functions (second line, second row), from top to bottom mass. ETMX is pretty clean in this configuration as the picth modes are well excited by the Stage 1 vertical motion.
Dave made these read only in the autoBurt.req file and I rescanned the channel list: H1:HPI-PUMP_EX_BSCRET_PRESS H1:HPI-PUMP_EX_BSCSUP_PRESS H1:HPI-PUMP_EY_BSCRET_PRESS H1:HPI-PUMP_EY_BSCSUP_PRESS
K. Venkateswara
I have attached ASD plots from 30k second-data from the BRS and the ground T240 seismometer x channel measured last night, when wind-speeds were fairly low. The first plot is in angle units and the third is in meters. I have also shown the tilt-subtracted ground super_sensor in red.
Both BRS and T240 look similar, but have no coherence. The amplitude of BRS looks lower between 8-20 mHz than the T240X, while it looks higher below that. Note that I have corrected for the transfer function of the T240 (double pole at 4.3 mHz).
The noise level between the two instruments also seems to vary with ground motion. Last Friday, Brian Latnz had suggested that it might be cross-coupling between different axes. This made me wonder if it was due to down-conversion from higher order modes of the beam-balance. I had seen similar issues with it in the lab at UW, which were mitigated when I added some vibration isolation in the form of rubber pads under the platform. So, I tried the same thing under the BRS platform on Monday morning. However, there was no change in the "noise" level as seen in the plots. It may still be cross-coupling in BRS or T240, but it doesn't seem to be the same type of down-conversion that I observed in the lab.
Changed the Local to Cartesian to Actuator matrices on HAM2 ISI to as per T1000388. Unlike HAM2, Guardian had no problem reisolating. Repeated several times, all good.
Committed to SVN. New Local to Cartesian to Actuator Matrices (Changed Monday but I didn't get snapped) saved.
The UIM coil driver S0900300 was modified as per E1400164. It was retested for noise and transfer function. The new, raw data will be zipped and posted to it's DCC record. Please inform me of any malfunction due to the removal/replacement of this chassis.
While preparing to revisit tilt decoupling at ETMX, I used the opportunity to correct the input and output matrices for the ISI. A new safe dot snap has been made and committed to the SVN. I will also be changing the guardian configuration and changing the blends, it will take a couple minutes to revert if anyone needs it back.
Aidan to check coupling between ITMX and ITMY Hartmann sensors Aidan to check alignment of the X arm CO2 laser on the compensation plate Richard checking Beckhoff for illuminators at the end stations Cable work in the LVEA Jim W. and Krishna to run tilt/decoupling measurements for ETMX SEI Doug to look at optical levers Jeff B. to bring in table from staging building on pallet jack 3IFO quad suspension assembly work continuing Rai W. running purge air and scrollpumps at ETMY for ionizer test end Y to be transitioned to laser safe
The heating test of the ITMX with the RH and coincident HWS measurement was successful. The usual negative thermal lens was observed to form in ITMX in response to 4.035W total electrical power into the RH.
t = 0 is defined as when the RH was turned on. tmax is defined as when the value of spherical power peaks.
The center of the lens is located at -[+2.1, -0.25]/(-135) m = [+16, -2]mm
Alexa, Kiwamu,
In response to Keita's alog about the PR2 baffle, we took a peek at the PR2 baffle by opening some of the viewports on HAM3 and HAM2 spool.
Conclusions:
(PR2 baffle check out)
We opened up a viewport on the East side of HAM3 which the leftmost one with an illuminator attached on. This was the only available viewport to open up. We removed the illuminator and looked at the baffle through the viewport. We confirmed that there was no cross bar structure on the side of the baffle unit as shown in the DCC document (D1000328). We could not see the top part of the baffle where it supposed to have a cross bar structure. We took some pictures and I attach them to this entry.
(Peek at the aperture position)
Then we tried a different zooming in the PR2 digital camera in order to have a better view so that we can determine if the aperture hole is in the middle of the baffle unit or not. With a help of flash light illuminating the PR2 baffle from the HAM2 East side viewport, we could clearly see the edge on both right and left sides of the unit as well as the edge of the aperture. It looked like the hole is centered with respect to the right and left edges of the unit. We took several pictures of it via the digital camera so that one can evaluate the position later if necessary.
(MC2 scraper baffle check out)
Then we opened up another viewport on the West side of HAM3 in order to see both MC2 and PR2 baffles. Though, the MC2 baffle was completely occulting the PR2 baffle and therefore we could not see it. We could still confirm that the MC2 baffle has a cross bar structure on the side as shown in the design document (D1000327).
The baffle hole seems to be centered in the baffle frame within 3mm from the picture. Good.
The distance from the left baffle hole edge to the left inner edge of the baffle frame is about 52 pixels, it's 56 pixels for the right, i.e. about 2 pixels offset to the left, which corresponds to 2 or 3mm.
Keita
The hole diameter is also good (i.e. the ratio of baffle frame width to the hole diameter on the picture reasonably agrees with the spec).
Switch between the first attachment and the second to see if you agree with my assessment of the edges.
| Nominal | Image | |
| Baffle diameter | 2.756" | 53px |
| Baffle height | 8.34" | 160px |
| Baffle width | 8.74" | 165px |
| Diam/Width | 0.315 | 0.321 |
| Height/Width | 0.954 | 0.970 |
| Center offset | none | 2px to the left ~ 3mm |
