We started welding in fused silica fibres this morning and now have 3/4 fibres installed. We plan to weld the final fibre tomorrow morning, followed by de-stress and hanging.

Travis, Gary, Giles

Aidan, Alastair, Dave H, Dave R, Albert L, Eric G, Thomas V.

Tidied up the plumbing on TCSX. Installed plumbing on TCSY. All three picomotor mirrors installed and confirmed to be working on TCSX.

Hooking up proximity sensors for flipper mirrors. Installed shutter on TCSX laser.

Morning shift covered by Corey

130 - TCS crew energizing laser on optical table at BSC3. Beginning to populate table at BSC1. Did I see Dave Reitze working on this?

various ISI/SUS trips throughout the afternoon as a result of commissioning.

New screens showing oplev path on the QUADS after updating what Stuart did at LLO. I made a small correction and commited SUS_CUST_QUAD_OVERVIEW to the svn. cf attached screenshot

Betsy and I stowed ITMx (see attached picture). Plan for this guy is to get the sealed door on the box later today or tomorrow, then leave it in the cleanroom until its ready to move over to the beer garden.  
Margot 

[Rich M. Arnaud]

ETMY GS13 V2 input signal was sitting at around 6000cts whereas the others at ~100 cts. Turning off/on the digital Gain + DWH switches brought it back to ~1000cts. Better. Though, it seems like there is still an offset that adds up to the signal.

Arnaud, Eric G, Apollo, Thomas

We've installed the optical lever with two levels of 1:10 whitening in hardware and complimentary de-whitening in software.
 
They are calibrated to micro-radians and I've attached a plot showing the linear response.  The difference in their gains is most likely due to their difference in beam width.
Pit_Gaussian_width = 2.02 mm
Yaw_Gaussian_width = 1.41 mm

H1:SUS-ETMY_L3_OPLEV_PIT_GAIN = 95.50
H1:SUS-ETMY_L3_OPLEV_YAW_GAIN = 69.33

H1:SUS-ETMY_L3_OPLEV_SUM_OUT = 20,000 counts.

(Daniel, Alexa)

We measured the dark noise and shot noise of the LSC RF PD in the refl path of the IMC.

1. Dark noise: We blocked the PD and confirmed this by looking at the H1:IMC_REFL_DC_OUT which went down to about 0.02 counts. The noise was measured to be approx 80nVrms/sqrtHz from the SR785.  For greater accuracy, we took the power spectrum of H1:IMC-I_OUT using DTT. The result is deipcted in (REF2) -- this measurement is in counts and must be calibrated using 20/2^16 V/cnts conversion with a factor of 100 to take into account the whitening filter.
2. Shot noise: We placed a light bulb in front of the PD and read back 8705 counts at DC (again, using H1:IMC-REFL_DC_OUT). The noise was measured to be approx 280nVrms/sqrtHz from the SR785. We also took a power spectrum of H1:IMC-I_OUT (the same calibration above must be applied). 

From this measurement we calculated the AC transimpedance of the PD to be 2.1kOhm (with a 100 Ohm DC transimpedance). 

Started off morning with many RED systems.  Jeff B walked me through getting everyone (SUS, HEPI, ISI) in BSC2 back & then went from there.

Days Activities:

• 8:45amWorking on EY Dust Monitor (Jeff B)
• 9-11:15 ETMy Oplev work!!! (thomas)
• Noticed Ops Overview for BSC3 ISI wasn't showing that we had a tripped ISI (Guardian led me to discover this)
• Common Mode work (Daniel & Alexa)
• EY PCal work (Craig)
• Keita transitioning EY to LASER HAZARD
• Increased Alarm settings for EY Dust Monitor since it has been alarming (chambers are closed and cleanrooms are now off at EY!)
• TCS Crew continuing work

-Had to leave shift at 1:30 and was spelled by Justin B.

Log-Log plot attached with T0 set to start of rough pumping (~700 torr).

Demonstrated MTP safety valve closes and turbo spins down with the removal of AC to the scroll pump -> This mimics the functionality of a loss of "Motor Run" signal from the nominal backing pump -> Shut down QDP80 and purge air supply

model restarts logged for Tue 01/Apr/2014
2014_04_01 12:39 h1susetmy
2014_04_01 12:39 h1susitmy
2014_04_01 12:42 h1broadcast0
2014_04_01 12:42 h1dc0
2014_04_01 12:42 h1fw0
2014_04_01 12:42 h1fw1
2014_04_01 12:42 h1nds0
2014_04_01 12:42 h1nds1
2014_04_01 12:51 h1susitmx
2014_04_01 12:52 h1susetmx

All restarts expected and part of Tuesday maintenance.

The attached log/log plot gives the estimate that it will take a little over three weeks
for the pressure to get to 3 x 10^-7 torr which will reduce to 1 x 10^-8 torr when the chamber
is open to the cryo pump.

There was a magnitude 8 earthquake in Chile, all BSC ISIs tripped. 

Y-end pumping interrupted for ~15 mins during valve install -> Flex line from MTP to Turbo Header can now be isolated at the MTP plumbing -> Flex line from MTP to locally mounted scroll pump can now be isolated at the MTP plumbing -> Currently both QDP80 and scroll pump are running, QDP80 backing MTP and scroll running but isolated from MTP -> ~500 watt scroll pump is currently being powered via an extension cord plugged into local vacuum 120VAC receptacle -> Would like to add a dedicated 120VAC receptacle local to the MTP control panel and eliminate the "scurge" of the extension cord

Since oplev damping might be used for Y arm commssioning as it is currently for X arm, I modified the QUAD_MASTER simulink model to have oplevs feedback on all the quads. 

• Created a common part called FOUROSEM_STAGE_OPLEV.adl living in /opt/rtcds/userapps/trunk/sus/common/models (copied from FOUROSEM_STAGE.adl) with a new path linking the oplev signal to UIM and PUM actuation (going through the DRIVEALIGN matrix) cf first screenshot.
• In QUAD_MASTER, the L1 and L2 parts were replaced with the newly created "FOUROSEM_STAGE_OPLEV"
• Hooked back h1susetmx and h1susitmx to QUAD_MASTER
• Modified the medm screens : Added a menu button at UIM and PUM levels. This screen might need to be revisited for clarity. Stuart is making a similar change at LLO with a better looking screen, so we will update when change is commited
• Took safe snapshots of the four quads with oplev switches off

Only FOUROSEM_STAGE_OPLEV.adl part was commited to the svn

Chris, Sheila

Our measurements of the COMM noise with the WFS locked have an rms of 20Hz, measured down to 0.1 Hz.  To make sure this was reasonable, we turned off the refl bias path so that the laser was locked only to the green beat note. The transmitted power fluctuations are noticably less than the HWHM of 40Hz, so this seems believable. (StripTool is the second screenshot attached). 

We wanted to try locking the arm half way down the fringe so we could make a measurement of the noise using the transmitted power.  Since the IR trans PD is normalized to 1 when the cavity transmission is maximized, the calibration of this signal is just a high frequency gain of 84 (FWHM of the arm cavity), and to correct for the refl bias loop gain we have a pole at zero and a zero at 3Hz.  The correct calibration has a more complicated frequency dependence, so we would have to do the real calibration to make a comparison above about 42 Hz.  Neither of these traces have the cavity pole at 42 Hz corrected for.  You can see that the side of fringe measurement agrees with the normalized refl PD signal well up to 100 Hz . (1st screen shot attached)

We repeated the measurement in the normal configuration, where we lock on resonance using the refl bias path, and the noise is the same (30Hz rms down to 0.02Hz). The RMS is dominated by the pitch mode, so we will work on increasing the WFS bandwidth tomorrow. Tonight we tried OpLev damping (this added noise around 1 Hz) and turning up the pitch OSEM damping gains (inconclusive so far). 

We redid the measurement with the WFS outputs held, and saw that the noise was high again (100Hz rms down to 0.1Hz), with the WFS on again we were back to the low noise state. So we can safely say the WFS are helping.

We also checked that the noise is the same from 3-100Hz with and without the refl bias path engaged. 

For future reference I took a spectrum of the 5 HSTS (MC1 MC2 MC3 PR2 PRM) from monday morning before the corner station was vented.

The isolation and damping on HAM2 and HAM3 ISIs were ON, and feedforward was OFF. The suspensions damping loops were closed. The chambers were under vacuum.

The attached pdf shows a comparison between the 5 HSTS, for every "mass" levels (M1 M2 and M3) and every degree of freedom.

Few things to notice on the plot :

- The performances are really consistent from one chamber to an other

- Signal is really close to sensor noise, especially at the bottom mass

- There is an interesting feature between ~0.1Hz and ~1Hz seen for longitudinal transverse and vertical dofs. This is something I would need to double check, but I'm pretty sure it is transmitted ground motion.