PRMI aligned; ready for real commissioning

I continued working on the PRMI alignment (see alog 13592) today and finally obtained good alignment. This should be good enough for proceeding with the next steps.

With the new alignment, the PRMI flashes without loosing the POP beam at ISCT1. In fact, one can now see PRMI fringing in the POP camera.

We are almost ready for some locking activity.

 

(Next steps)

• Re-configure the POP path on ISCT1. (Right now, an analog camera is blocking the beam and no beam is on the POP photodiodes.)
  • POP is necessary for triggering the LSC feedback.
• Setup a digital camera in the ASAIR path.
• Align and lock MICH
  • We can now use the AS demodulated signals !
• Lock PRMI

 

(alignment)

From the experience yesterday, I learned that a combination of PR2 and PR3 did not improve the POP/PRMI alignment situation for some reason. In fact, it made the forward propagating beam hit the west side of the PR3 suspension cage. Therefore, I wanted to move the input pointing in order to introduce a translation in the cavity axis in the downstream after PR2 while keeping the POP beam angle (almost) the same. To do so, I touched IM4 in yaw. This then required re-alignment of PRM in order to maintain the beam at the REFL port. Also, every time I changed the alignment of IM4, I compensated it by steering PR2 such that I keep the POP beam at ISCT1. I repeated this process multiple times. This was successful. I could eventually obtain an alignment setting where the PRMI flashes with the POP still visible at ISCT1. The attached is the new alignment settings.

After the PRMI alignment, I re-adjusted the PR3 alignment such that the beam reaches HAM6 and ISCT6. I did not check the beam centering on the SR mirrors.

 

(fun locking)

Since I was running out my energy, I decided not to try the PRMI locking tonight. Instead, I locked PRX for fun. I just used REFL_A_RF45 for now. The ASAIR_LF signal was used to check if it is locked on the carrier or rf sidebands. The attached is time series of some DC signals at the AS port when locking PRX. It is locked on the carrier.

Since PR2 and PR3 are close in the Gouy phases, this combination is not very good for the prc alignment. IM4, PRM and PR2 (which is almost same as PR3 and BS in G phase) have some separations each other. A combination of these three will work.

ISCT6 in place, ASAIR and OMC_R successfully extracted

Kyle, John, Keita, Dan, Koji, Filiberto, Gerardo, Kiwamu

The ISCT6 enclosure is now in place by HAM6 with two light pipes installed. ASAIR and OMC_R are successfully extracted to the table.

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We craned the ISCT6 table from the squeezer bay over to the north side of HAM6. We carefully adjusted the position of the table by rolling it. The table legs were then secured on the floor. With help from Gerardo and Filiberto (a big thank you for Gerardo and Filiberto who machined the holes for us even though the working hour was over !), we made a 10 inch beam penetration hole on two back panels of the enclosure . These are for the ASAIR and OMC_R beams respectively. Note that we could not see a bright enough OMC_T beam this time and therefore we did not try to make a hole on the last back panel. This will be don once we reliably confirm the OMC_T beam position. We put the flanges and light pipes for the two beams and now the beams are successfully coming out to the table.

Also, in the process of trying to find the OMC_T beam, we turned on the PZT high voltage. We need to make sure that the high voltage is off when we pump down the chamber tomorrow.

HAM6 Viewport Installation

Installed 3 high quality viewports on the North door of HAM6, positioned on A2F3, A2F4 and A2F5. Two ZV-800 viewports were installed on the East door, positions are BF2 and BF3.

Checking ESD wiring at ETMX and comparing with ETMY

Borja

I just came back from a quick visit to End-X (UTC 2014-08-27 00:25:00).

I took some pictures (see attached) at the feedthrough wiring for the ESD at BSC9 (ETMX chamber). I compare it with the ones I took a while back at ETMY (see attached).

There is an obvious difference, the red insulating tape at ETMY wiring which does not show at ETMX. The wire which has the insulating tape carries VBIAS to the ESD at ETMY. The reason for the insulation is that the coax cable's shield is cut off because the corresponding coax cable inside the chamber has the known issue of having the shield connected to the center lead. This problem is non existen at ETMX.

This is another big difference between both masses which may be related to the more stable results on the charge measurements observed at ETMX.

We need to fix the shielding in any event. The shield now acts as a large capacitance coupling of the electrode to the chamber and
will inevitably cause cross talk and noise in later operations.

Ops Shift Summary

7:58 – Checked the Crystal Chiller water level (Maintenance)- Operator
8:15 - 8:30 Morning Meeting
8:25 – SPRAGUE on site
8:47 - Pulling cables all around the LVEA – Aaron/Ed
8:48 – Heading into H2 PSL enclosure in LVEA – Peter
9:15 – Cameras installation in LVEA – Filiberto
9:22 – Heading into the LVEA to work on SR3 Optical levers – Jason
9:44 – Back from LVEA – Peter
9:45 – Getting 3IFO(Quad#8)ready to be moved to its storage location – Jeff B.
10:04 – Working on ASC model – Dave
10:12 – Returned from LVEA – Jeff B.
10:22 - Reset HEPI overflow counters for HAM2, HAM3, HAM4, HAM5, ITMX, and ITMY (Maintenance) – Operator
11:43 – Back from the LVEA – Aaron/Ed
12:41 – Heading to End X (Cleaning) – Chris
13:37 – Heading to End Y (Cleaning) – Karen
13:46 - Heading to End Y to work on Low frequency microphone – Sudarshan
14:14 – Returning from End Y – Karen
14:18 – Back from End X – Chris
15:01 – Heading into the LVEA – Jason
15:07 – Working at End Y (Valves operation) - Kyle

H1 installation milestone: The last chamber was closed.

Gerardo has just torqued down the bolts for HAM6 viewports. We're done with H1 in-chamber installation (for the current configuration)!

~1525 hrs. local -> Valved-in IP11 @ Y-end, Valved-out turbo

At request of Borja

Low Frequency Microphone

S. Karki, Dave Barker

Troubleshooting low freq Mic at ENDY and CS:

1. The power to the DAQ (sitting on top of each microphone) was reset by pugging off the power supply cable and plugging it back in.

2. The signal cable were switched to a known working channel.

Both resulted in no difference to the signal output suggesting that the microphone itself could have been damaged. The signal from the mic seemed to have stopped since the last power glitch.

Switching from the currently used CS microphone to the extra one sitting on the floor solved the problem, suggesting that microphone is bad.

Removed Ring Heater and Cable Assemblies from H2 ITMy

Removed the Ring Heater Assembly from the ITMy quad structure going into 3IFO storage. Before starting I noticed the lower ring heater assembly had a crack in the glass former. Not sure when the break happened, but this one also displayed a lot of movement inside the ring heater shield. The pictures show how the former has pushed pretty far out of position. 

The ring heater cables were also removed. This includes the "antlers" (D1001755) but not the plate (D1002420) which the earthquake stop is attached to.

The assemblies removed were:

ASSY-D1001895-V5 #001 (lower ring heater, broken)
ASSY-D1001517-V7 #612 (cable assembly)
ASSY-D1001838-V6 #005 (upper ring heater)

That should read

ITMx (not y)

and

ASSY-D1001838-V6 #002 (upper ring heater)

not #005. typos.

One more fix. The lower ring heater should be:

ASSY-D100195-108

Made a mistake with a V5 and V6 part.

EndY ETMY Yend HEPI Pumps off since 12 August

This last occurred at EndY 5 Aug but it wasn't restarted until 11 August.  So barely 24 hours later it dropped out again.  14 August was the power outage and it appears no restart attempt was made at EndY.  EndX is running at this time.  Borja is taking data at the moment and asks the optic not be disturbed.  This restart will require a trip to the EndY MR.

three analog cameras installed on output chambers

Filiberto, Kiwamu (WP4816)

We have installed three analog cameras that are going to monitor the signal-recycling mirrors (i.e. SR2, SR3 and SRM) on HAM4 and HAM5. We put a good TV lens on each of them and adjusted the aperture and focus.

The detailed location of the cameras are described in the viewport final design document (page 54 and 55 in DCC-T1000746-v7) and we followed it.

CDS model and DAQ restart report, Monday 25th August 2014

no restarts reported.

OPS: reset of HEPI L4C Accumulated WD Counters Tuesday 26th August 2014

Maintenance: Reset HEPI overflow counters for HAM2, HAM3, HAM4, HAM5, ITMX, and ITMY 

ETMY charge measurements with the Ion Pump gate valve closed

Borja

Yesterday's results in ETMX although positive from aLIGO operation point of view (no charging mechanism was observed based on green light and ion pump) however it was discouraging from the point of view of providing answers to the big charge changes that were observed in ETMY. If the ion pump was not charging the mass then what was doing it? Is this unexplained behaviour in ETMY charge changes casting a shadow over the charge measurements methodology? Fortunately a new set of measurements in ETMY that were taken during the experiments at ETMX confirms that the measurement method is reliable and it also tells us what is charging ETMY. For a period of 62 hours 6 charge measurements were taken on ETMY, for all these measurements the ion pump gate valve was closed. The results are remarkable in their consistency and stationarity of the charge values for all quadrants and for both orientations (pitch and yaw) within no more than 20Volts (less depending on the quadrant and orientation). The charge values agree with the last measurement taken just before closing the ion pump gate valve.

The amount of measurements make it impractical to show a summary table like in my previous aLog so this time I go for a more friendly graphical display. As always attached are the measurement documents and the standard VBIAS vs normalised deflection plots comparing each measurement with the ion pump gate valve closed with the first one, and the first one with the one previous to closing the valve.

So what is different between X and Y regarding the charging effect of the ion pump? mainly 3 differences:

1) The Earth magnetic field

2) The pressure being different by an order of magnitude. The pressure in end-X is 2.7e-7 torr while in end-Y is 4.8e-8 torr. A higher preasure will reduce movement of the ions, but at the same time the higher the pressure the more charge is emitted by the ion pump (see attached document "charged_particle_emiss_ion_pumps.pdf").

3) Both ion pumps were costume made to the same specifications. They are made of 50 smaller ion pumps so maybe the way these were configured is different for each final ion pump.

Next I show the summary plots of all measurements taken so far both for ETMX and ETMY. Each mass has 2 set of plots; Veff and slope of normalised deflection vs VBIAS. Each set of plot is divided in 2 subplots, one per deflection orientation (pitch and yaw).

ETMX:

ETMY:

The numbers in the plots represent the major changes that took place at the time of the measurements. These are summarised next:

1) 1st ionizer discharge.

2) 2nd ionizer discharge.

3) Wire swap to right configuration: BIAS going through the ESD LP filter box.

4) Wire swap to wrong configuration: LL quadrant driver going through the ESD LP filter box.

5) Wire swap to right configuration and Final: BIAS going through the ESD LP filter box.

OM1 and OM2 coil driver Vmon are not properly working

Keita and Kiwamu

In order to investigate the large cross coupling issue in OMs (alog 13575 by Dan), we checked the OM driver electronics.

We found that the OM1 and OM2 coil driver Vmon are not properly functioning. However, this does not explain the cross coupling that Koji and Dan experienced.

Anyway, these two coil driver chassis (S1200614 and S1200612) need to be swapped at some point.

 

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(some details)

When we started looking at the OM screens, we immediately noticed the LL voltage monitor of OM1 and OM2 displaying anomalously high voltage while the zero DAC voltage were requested. OM1_LL showed approximately 23000 cnts and OM2_LL showed approximately -23300 cnts. Even so, these channels were still sensitive to the bias we sent through the DAC -- we could change the readout values by changing the biases. But they did not go to the other sign in the readout voltages.

We then went to the electronics room to check out the analog circuits. Looking at DB9s' signals for the Vmons by inserting a 9-pin breakout board, indeed we saw LLs exhibiting a funny voltage. LL of both OM1 and OM2 were at -14 V when the zero DAC voltage were requested. Then we went to the AS port rack to check if this is also the case for the actual drive signals. However the drive signals looked healthy on both OM1 and OM2. We checked this by looking at the signals at the input of the satellite amplifiers. All the signals could swing from -22 to 22 V as we changed the DAC voltages.

We are concluding that the Vmon part is not properly functioning in the OM1 and OM2 coil drivers. But, since the actual drives are healthy, this issue is independent of the cross coupling issue.

By the way, the OM3 coild driver looked healthy and its Vmon looked fine. So we did not check them.