Alexa and Sheila have turned on the laser in the HAM 6 bay.

The ref cav power has been dropping over the last two weeks.  I lowered the resonant threshold so that we could lock the MC for work in HAM1, but we probaby need to look at the alignment. 

Attached are plots of dust counts requested from 4 PM October 6 to 4 PM October 7.

Will finish tomorrow

Currently RM1 and RM2 are still in acquire mode.

Attached is a coil output signal plot in cts, with a calibration that mimics the the anti-dewhitening filter is applied. The RMS will still be <200cts, and that's with the purge air running.

This will require putting jumpers in the RM1 and RM2 coil drivers (4 each).

At the same time the OM1,OM2 and OM3 coild drivers can also be jumper-ed for RUN mode and to permanently enable them (2x4 jumpers per coil driver).

930 SnoValley to EX

930 Sheila transistioning LVEA to laser safe

1000 Thomas working on ACB and MCB in LVEA

1038 Apollo begins removing extra piping along X-manifold (WP 4171)

1100 Jeff K restarting H1ASC

1250 Filiberto and Aaron to EX to work on cabling

1300 Cheryl to EX to make everything peachy in the TMS lab

1440 Rich and Alexa to EX to inspect cabling

1515 T-Vo and P-Tho restarting IO/PSL environmental chassis

on Friday Kiwamu and stefan moved the tip tilts according to the calculation. Yesterday Stefan and I both remeasured these positions, what we got is that the distance from RM1 to RM2 is sqrt((17*2)^2+1^2)=34 inches.  The distance from RM2 to M5 is sqrt((18*2)^2+6.5^2)=36.6 inches.  We moved the BS for the refl LSC detector to 31 inches from M5.  

When we first started making beam measurements we got some not repeatable results, because the beam was moving alot.  With no one in the chamber or on the platform and the tip tilts damped we got repeatable results.  With the mode master placed 22 inches from the beam splitter in this position we measured the beam using mode master ( we got a maximum gamma error).  The result is in the attached photo P1000690.png.  We also made measurements with the mode master 31 and 3/4 inches from the BS, this measurement is also attached as P1000689.png

This afternoon we also used the nanoscan to measure the beam waist (with the BS in the same position).  These are saved on the Nanoscan computer and I will add them to this post in the morning.  

I have also attached some plots to help compare our measurements to each other and to Paul's calculated beam (and the script).  Summary_Hor and Summary_Vert show Paul's calculation, our measurement before the TTs, and our two measurements after the TTs after we moved them to their current locations, with all of these beams propagated through the refl WFS path in HAM1.  The magenta and green curves are the two mode master measurements made about a foot apart after the tip tilts, the green line is almost not visible because these two measurements agreed with each other.  The plot shows each of these four beams propagated back to before any of the tip tilts, and compared to the nanoscan measurement we made before the tip tilts (the first tip tilt has been deleted to allow the comparison).  The last plot shows all four of these beams compared to the nano scan measurements we made after the tip tilts (with L101 deleted).  The nanoscan results are intermediate between Paul's calculation and our mode master measurement before the tip tilts.  

The gouy phase separations based on each of these beams is:

So, although the agreement between our measurements (and calculation) aren't great, at least it seems clear that the gouy phase separations were improved by moving the tip tilts.  

Following the SEI group sign-off on the BSC3 Cartridge, I started cleaning up the ISI today. So far, electronics are powered down, all cabling is disconnected (in-air and in-vac), CPS racks removed, ISI locked, test stand nuts removed, all the hidey-holes in St0 checked for loose tools and all in-vac cabling is stowed. There are still some loose parts on the ISI to be removed (keel mass and other masses that were used in testing), lift pads need added and the ISI needs covers. The cleanrooms also need to be re-arranged, non-cartridge clean items need to be stowed in the neighboring clean-room, and a path needs to be cleared to allow the cartridge cleanroom to be moved out of the way prior to flight. Shouldn't take more than a couple of hours to finish prep, though.

Jim and I cabled up the Beckhoff serial lines at EX last Friday. This afternoon Daniel completed the Beckhoff configuration to read out the timing diagnostics from the EX Timing Fanout Unit into EPICS. The diagnostics are available on an MEDM screen, from the SYS part of the site overview (see attached). I need to add these diag channels to the DAQ tomorrow.

I have attached pictures of HAM1 with everything installed.

Alexa, Rich

After dressing in all the in-vacuum cabling in HAM1, we took final RF transfer functions of all detectors at their respective operating frequencies.  These transfer functions are taken from the ISC-R2 rack (patch panel connector for LSC detectors, and terminated cable ends for ASC Detectors.

The cable (type LMR-195) has an RF loss of ~2.5dB per 100 feet and a velocity factor of 0.76.  The cable length from rack (as measured by time domain reflectometer (TDR) is 43 feet to flange, 57 feet to detector).  The in-vacuum cable is a flexible RG316 equivalent made by Gore Inc. The velocity factor is approximately 0.7 for this cable.  The measured loss of this cable (done at CIT) on a 10.5 foot section is: 
0.28dB at 9MHz
0.50dB at 36MHz
0.56dB at 50MHz
0.84dB at 100MHz

All transfer functions taken from test input to RF outputs.  Don't forget to enable the RF test switches for the LSC detectors, then disable them once you are done measuring to avoid an unnecessary noise introduction path into the LSC detection chain.

LSC POP-9MHz  17.0dB
LSC POP-45MHz  17.1dB

LSC REFL-9MHz  17.7dB
LSC REFL-45MHz  17.4dB

ASC REFL A-9MHz Quadrant1  5.7dB
ASC REFL A-9MHz Quadrant2  5.9dB
ASC REFL A-9MHz Quadrant3  7.5dB
ASC REFL A-9MHz Quadrant4  6.9dB
ASC REFL A-45MHz Quadrant1  5.5dB
ASC REFL A-45MHz Quadrant2  5.8dB
ASC REFL A-45MHz Quadrant3  5.6dB
ASC REFL A-45MHz Quadrant4  5.4dB

ASC REFL B-9MHz Quadrant1  4.0dB
ASC REFL B-9MHz Quadrant2  5.5dB
ASC REFL B-9MHz Quadrant3  4.1dB
ASC REFL B-9MHz Quadrant4  4.4dB
ASC REFL B-45MHz Quadrant1  5.4dB
ASC REFL B-45MHz Quadrant2  5.5dB
ASC REFL B-45MHz Quadrant3  5.9dB
ASC REFL B-45MHz Quadrant4  5.6dB

I used thenano scan to measure a beam profile on IOT2L.  near the periscope, the vertical waist diameter is 4411um.  The horizontal beam isnot gaussian, the waist diameter fit is 4007um.  (screen shot is first image attached to this report) This was taken 3 and 1/2" from the bottom periscope mirror, the periscope height is 23 and 1/2 ", and the top periscope mirror is approx 2'8 and1/2" from the viewport.  This data is saved as IOT2L1 on the nanoscan computer.  

I moved the scan head back to  14"  behind the botttom periscope mirror, and measured 4405 um diameter vertical , the horizontal beam still is non gaussian, but the diameter is 4070 um.  (screen shot is second image attached)

This data is now transfered to http://www.ligo-wa.caltech.edu/~sheila.dwyer/NanoScanData/IO/

J. Kissel, S. Ballmer, C. Wipf

After discussions with both Chris and Stefan, I have re-arranged how the IMC WFS' master switch, gain, and trigger bit are combined such that the implementation is a little less obfuscated and well-annotated in the Simulink model. I attach a new screenshot. In this new arrangement, each of the three variables -- all nominally 0 (zero) or 1 (one) for OFF and ON, respectively -- are simply multiplied together by one block, as opposed to feeding the trigger into a switch block that compares its value against the master switch (nominally 1 [one]) and a ground (equivalent 0 [zero]) [See identically named screenshot in LHO aLOG 7984 for previous implementation]. 

For historical purposes: Stefan had originally implemented the triggering with the comparator switch for philosophical reasons in that (at least with conventional c-code) it is bad practice to assume a trigger could only be 0 or 1 -- typically when programming in c, a flag is either zero or non-zero, where non-zero can be anything and should never be assumed to be one. However, the trigger library part used (from ${userapps}/release/isc/common/models/LSC_TRIGGER.mdl) is written to ONLY spit out a 0 or 1. Therefore this bad-practice failure-mode dos not apply, and we are free to make the output bit generation more clear.

As of this entry, the 
${userapps}/release/asc/h1/models/h1ascimc.mdl
has been re-compiled, re-installed, re-started, and re-stored. Since the mode cleaner is dead for the time being due to venting of the corner volume (light from the PSL has been shuttered), I cannot *confirm* all is still functional, but I'm 99% confident all is well.

Joe, Pablo, Cheryl, Sheila

We measured the beams coming out of the HAM2 viewport, with the nanoscan head 2 feet 6 inches from the viewport.  (in the first version of this alog I wrote the wrong distance)

For the brighter beam we measured beam diameters: 2549 um horizontal, 2632 um vertical.  after rorating the scan head 90 degrees we measured 2650um vertical, 2561 um horizontal.  

For the dim beam we measured 7160um vertical, 5972 um horizontal after rotating  by 90 degrees we got 6077um horizontal 5865um vertical. 

We also measured the beam in HAM1, in the same location as wensday (we move the BS for the RF PD to 16 inches after M2, we put the nanoscan 40 inches after the BS, there we got 4025 um vertical, 4126 horizontal.  After rotating the head 90 degrees we got 4045 um vertical 4020um horizontal.  

We placed Mode Master downstream of three-mirror Gouy phase matching telescope comprising two tip-tilts and one fixed mirror that is used for REFL WFS. (See the last picture for layout and distances.)

Note that the measured TT1-TT2 distance is about 1cm shorter than nominal described in Sam Waldman's document (http://dcc.ligo.org/T1000247), TT2-M5 distance is about 14mm longer than nominal, both of which should have been quite acceptable.

Anyway, we made this measurement and the beam was much smaller than what was expected. The first plot as well as the table below show the measured VS  the expected mode profile coming out of HAM1 propagated through the telescope with the measured mirror distances.

The total mode overlap between the actual beam and what is expected is somewhere between 0.75 and 0.87 (sort of tedious to do the real calculation so I leave it).

The 2nd plot shows that IF the incoming beam from HAM1 is as expected, in order to explain the measured mode the TT1-TT2 distance labeled as delta1 should be shorter by 4.5cm than was measured for X, or by 5.7cm for Y. This is a huge number, there's no way my distance measurement was that much off.

The 3rd plot  shows the Gouy shift between TTs (i.e. actuation orthogonality) and WFSs for the WFS sled (i.e. sensing), and it seems like both are quite poor for the measured mode, 26deg for actuation and 35 for sensing are sad though not a complete disaster.

Anyway, since it's hard to imagine that the ROC of TT1 (+1.7m), TT2 (-0.6m) and M5 (+1.7m) are grossly wrong, and since it's hard to imagine that the distance measurement has a 5 to 6cm error, this should mean either (or some) of the followings:

1. T1000247 is wrong about the mode coming out of HAM1.
2. IMC mode is not mode matched to the IFO well.
3. Astigmatism of curved optics at an angle (there are 3 such optics on HAM1, more on HAM2), each has small effect but maybe they add up. Neither Sam nor I have included this.

The third one doesn't sound likely, but neither Sam nor I have thought about this.

Patrick T., Thomas V.

Last night Thomas and I swapped the temporary cables being used to test the rotation stage in the CSR with the ones made for the final installation. These are not pulled yet, but are coiled in front of the rack holding the Beckhoff PSL environmental chassis and attached to a rotation stage sitting on a rolling table nearby.

For some reason two cables had been unplugged from the controller box (goes between rotation stage and Beckhoff module). One was power and the other was a control cable. I'm not sure why they were unplugged, but we reattached them.

I was hoping this would address problems we were having getting the rotation stage to move, but they have persisted.

This is a list of the ISC diagnostic optics in HAM1. Some of these are yet to be installed,  but all will be installed in this installation window.

The only differences between this and D1000313 are:

1. M14, the first BS for the REFL, is a 90% S-pol splitter (E040512-B4), not a 95% P-pol (E1000871-V1-02) as in D1000313, as the reflectivity of the latter was measured to be too much for our purpose.
   • However, 90% is a bit too small, and we might want to insert another 50% splitter later.
2. For M6 (50% P-pol splitter), we used iLIGO REO splitter (E040512-B1, marked "IO824-01" on the barrel) instead of newer ATF optic (E1000671-02) because I couldn't find the latter.
3. We put a black glass behind M5, as all high reflectors upstream of M5 are with some kind of beam dump.

Note:

• The optics with ? in the S/N column just means that I don't know them for now.
• REO optics have markings e.g. IO824-01 on the barrel, but they don't seem to be consistent over the coating type. For example we have IO822-08, IO823-07, IO823-01, IO826-08, IO826-05 and IO824-07, and these are all 50% P splitter.
  • These might be the production run number ("IO824") and the serial number ("-01") for the substrates, but not for the coating. If that's the case we cannot automatically look up the coating type from these numbers, but I'm hoping that each of these numbers is at least unique so I can use these as ID.