(Michael R., Rick S., Oliver P.)

After turning on the high power satge, the amount of light in the FSS path was about six times higher than in the low power mode. To operate the FSS properly, the amount of light at the RF photodiode had to be attenuated. Therefore, we add an additional R=80% splitter to the beam phath. Also, the lens, focussing the beam to this diode had been exchanged: the focal length is now 100 mm instead of 50 mm, which gives more space for the beamsplitter, the diode itself, a stirring mirror in front of the diode and a beam dump, blocking the light, reflected from the chip (see the attached picture).
We were able to lock the FSS. The measured parameters are as follows:

power downstream of the Faraday isolator behind the reference cavity:  39.0 mW

DC voltage at photodiode in reflection, if locked: 0.052 V

DC voltage at photodiode in transmission, if locked: 1.119 V after optimizing lambda/4 wave plate

We adjusted the unity gain frequency using RF analyzer. The common gain has been set to 16 dB. We found the unity gain frequency at 309 kHz with 44 deg of phase margin.

If the FSS remains unlocked, the powers and voltages are:

RFPD DC 0.386 V

incident on RefCav 73 mW --> 86.5% visibility (including sidebands)

total power transmitted by RefCav: 43.5 mW

h1dc0 disappeared from medm screens running on the OPSLAN. Initially I thought it was a cds-h1fe epics gateway error and I restarted that, but it did not fix the connection. I ran a DAQ MEDM on the FELAN and verified h1dc0 was running correctly, at which point the OPSLAN MEDM came to life but showed the EDCU disconnected from 1130 channels. I logged into h1dc0 and it verified it was not connecting to 1130 channels but did not give a disconnected channel list. When this had happened before we suspected the Beckhoff OPC-IOC and its epics gateway, so I restarted the h1slow-h1fe gateway, which did not fix this. Vincent needed a DAQ restart, after the restart the EDCU was happy again. Looking at channel lists in EDCU  ini files I cannot find a single system with 1130 channels in it.

Transfer functions are running overnight on HAM2-ISI.

At 07:10 this morning the IOP model on h1seib2 (Beam Splitter Chamber) showed an IOP timing error. The IOChassis timing slave looked to be clocking correctly. A model restart did not clear the problem so I performed a full frontend-IOChassis power cycle. It was found that somehow a duplicate B2 IOP EPICS process has been incorrectly running on h1seib3 since april 11. This was presumably a cut-and-paste error when B3 was built for the first time. I power cycled h1seib3 to ensure it only runs B3 processes, which it now does. The error on B2 went away on hard power cycle, why it appeared this morning remains a mystery.

 - Tyler (Apollo), Cheryl

Panel is on the table enclosure - bellows is not installed - opening is covered with ameristat to maintain positive pressure.

[Chris W. Mark B. Arnaud P.]

Thanks to the generous help of Chris, the problem of binary I/O control has been finally solved. The routing of the monitoring signals was wired incorrectly in the model. More details in the attached screenshots.
First picture shows what part in the model has been modified, the two others show the actual change.

The model has been commited on the svn. LLO model is consistent with LHO.

WP 3852.

The following computers were renamed at EY

All corresponding IOP models were also changed. User models which run on these front end needed a minor change to the "host=" component of their CDS part. User models which were changed are: h1susetmy, h1sustmsy, h1hpietmy, h1isietmy, h1pemey, h1iscey and h1susauxey.

Instructions for changing the computer name, and changing the IOP model names are given in the LHO CDS Wiki pages

https://lhocds.ligo-wa.caltech.edu/wiki/RenamingFrontEndComputers

https://lhocds.ligo-wa.caltech.edu/wiki/RenamingFrontEndModels

The IOP models have no fast channels being acquired by the DAQ, but their slow channels minute trend data was preserved by renaming the raw minute trend files on both frame writers.

The DAQ was restarted many times during this transition. MEDM screens, alarm handler files were modified as part of this work.

After the user model restarts it was noted that h1hpietmy showed an ini file change.

This closes WP 3852

[Dick, Kiwamu]

 We took a look at the IMC demod phase shifter [1] which had been found to be out of Beckoff's control the other day last week [2]. The conclusion is that it magically recovered by itself and became under Beckoff's control again. Anyway we set the delay by the hardware switches and disabled the digital switching as this is relatively safer than setting it digitally. There should be no impact on the IMC locking.


The optimum delay setting
   The delay is set to be 14.4375 nsec (= 1/16 + 1/8 + 1/4 + 2 + 4 + 8 nsec)
 where the I signal is maximized. This corresponds to a step setting of 231=(1+2+4+32+64+128) in the digital system. Note that the IMC modulation frequency is at 24078360 Hz.

The Symptom
 The symptom we saw last week was that the delay time didn't change when we changed the digital values in the corner Beckoff. I don't know what had happened to the electronics and digital system. Somehow we were able to change the delay from the Beckoff today.

The right half of the device is not functioning
 This is not important. A sad thing we found is that the right half of the delay line device doesn't seem working for some reason. We are not going to fix this because we haven't been using it and also we are not going to use it. Dick found that the loss of the circuit heavily depends on the amount of the delay and sometime it can reduce the ~15 dBm input signal down to -20 dBm or even less at the output port. We are guessing that there is some kind of loose contact in the circuit.


[1] DCC S1103425
[2] LHO alog 6265 "IMC locked, relocking well, visibility is good, but not TRANS beam, as it is clipped by it's bellows."
 

Since the IMC test, the ISIs of the input arm were subject to payload changes and mechanical adjustments. 

Activities From Today Mostly In Order Of Occurence

Apollo working in South Bay (causing some HAM2 Dust Alarms)

Oli working at PSL

Snow Valley switching Xarm Chillers & cleaning chillers on site

ISC Cable-pulling (mainly Input)

LVEA Crane survey continues

David is re-naming computers/models/medms at EY & needed to take DAQ down as well (also went out to re-label at racks and check on HEPI Servo work)

Installing HEPI Pump Servo at EX / Replace HEPI Pump Servo Lid at EY / Run new fiber for HEPI Pump Servo at EX & EY (Filberto & Aaron)

Paradise water at 9:53am

Tyler installing a panel at IOT2L

Oplev work at BSC2 & Y-Beam Manifold (Thomas)

BSC2 SEI Front End alarmed this morning at 7:05am (will require a reboot)...but it looks like the issue was more subtle & involved (and included BSC3) (Dave B.)

MX Weather Station work (Patrick)

EY Transitioned to Laser SAFE at 12:45pm (Sheila)

PCal work in H2 PSL room (Pablo)

Mark B. and Thomas Vo

Thomas is extremely close to plugging in the ITMy OL and this is maintenance Tuesday, so I changed the h1susitmy model to conform to D1100022-v9 (OL signals at ADC0, channels 4-7 rather than ADC1, channels 0-3 as left over from H2). 

The updated model is running and has been committed to the SVN.

Jeff Kissel and Mohana Mageswaran are working on an update to D1100022, so it's not inconceivable that the mapping could change again, but it's the best bet for now. 

Daniel rebooted h1ecatey while trying to debug the problem with epics communication

The Apollo crew and I spent some time sorting Install Tooling (HAM Arm, BSC Arm, 5-Axis Table) so that it could be palletized and stored in a reasonable location. A storage location was picked out: along the south side of the HAM 10-11-12 run. The tooling was not moved to the storage location today due to work on the main crane.

I moved all remaining items from the SEI Test Stand cleanroom to the SUS Test Stand cleanroom. I'll have the cleaning crew start the cleaning process ASAP.

The Staging cleanrooms closest to HAM2 continue to have high dust counts. I confirmed the function of the iLIGO particle counter with a recently calibrated aLIGO particle counter. I made sure parts/tools were covered and then confirmed that both cleanrooms were plugged in. I will pursue this some more tomorrow. We were planning on a retrofit for the green cleanroom anyway so we may just take care of it now.

Wrote up some code to handle the output from Testo 645 dew point probe. Much thanks to Arnaud for helping me debug an issue with that. The BSC destined for ETM-X is purged in its storage container. Once again the storage containers seem to ship down much faster than the shipping containers. I'm not sure why this would be the case, it may be related to the different seals.

I looked for signal on MC2 TRANS during the IMC locking at 250mW and found that the QPD does have light and is seeing the locl-unlocked transitions and DC changes (100mW to 250mW).  A plot showing the signals is attached.  

Offsets were hugely wrong for the segments, so SUM is -70 unlocked and -60 locked.  This prompted me to fix the offsets for MC2 TRANS and IM4 TRANS.  New values listed below.

MC2 TRANS

old offsets
15.0
47.0
-6.0
20.0

new offsets
1.4
1.4
1.6
1.8


IM4 TRANS

old offsets
-9.0
-26.0
-26.0
11

new offsets
1.5
0.5
0.7
1.6

Before modifying the BSC-ISI model to introduce the sensor correction on stage 1 using the STS-2, I cheched the coherence between the ground instrument and the T240s (stage 1). Note that the measurements were taken with the ISI undamped and the HEPI not controlled (Last night).

Measurement parameters are shown in the attached figure.

- Joe D., Cheryl

Joe and I uncovered the PSL viewport - the double viewport on HAM1.  The shutter assembly was disconected from the viewport and slid back to give us a full view of the viewport surface, and it is covered with particulate.  The source of the particulate on the viewport is the shutter assembly and cover plate.

There are two areas with a very high concentration of particulate, and it was quickly apparent that they line up exactly with two through holes that attach the shutter box to the viewport cover  plate.  The particulate in these two areas are uniform size and finer grained than the other particulate.

There is particulate that is concentrated at the exit of the tube from the PSL that is various sizes and is concentrated on the middle to bottom third of the viewport.

There are also some large particles scattered across the viewport.  One looks like a fiber, and the others could be fibers, hair, or thin metal shavings.

I looked into the shutter assembly and saw that the shutter itself has worn away the anodization on both sides of the shutter box, and there is particulate on the shutter's surface.  

One cluster of particulate on the shutter lines up with a through hole on the top of the shutter box.  The screw holds the removable plate that allows the input beam, reflected from the viewport, to project onto the PSL enclosure wall.

The shutter assembly needs to be removed from the viewport, modified and cleaned, and then reinstalled.

The viewport needs to be cleaned, but most of the particulate is metal.  FC is our usual choice for viewports, but with this level and type of particulate, scratching the viewport surface is possible.  Other procedures that are possible in the optics lab may also scratch the viewport.

Attached are plots of dust counts > .3 microns and > .5 microns in particles per cubic foot requested from 5 PM May 5 to 5 PM May 6. Also attached are plots of the modes to show when they were running/acquiring data.

mode
Connecting to NDS Server h1nds1 (TCP port 8088)
Connecting.... done
T0=13-05-06-00-00-00; Length=86400 (s)
2340 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

status
Connecting to NDS Server h1nds1 (TCP port 8088)
Connecting.... done
T0=13-05-06-00-00-00; Length=86400 (s)
2340 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

.3 microns
Connecting to NDS Server h1nds1 (TCP port 8088)
Connecting.... done
T0=13-05-06-00-00-00; Length=86400 (s)
2340 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

.5 microns
Connecting to NDS Server h1nds1 (TCP port 8088)
Connecting.... done
T0=13-05-06-00-00-00; Length=86400 (s)
2340 seconds worth of data was unavailable on this server
1440.0 minutes of trend displayed

ISIs (BSC1, BSC2, BSC6)
With the recent measurements (in vacuum), I created sets of filters for the ISI-BSC1, ISI-BSC2, ISI-BSC6. I installed:
- Compensation filters
- Calibration filters
- Symmetrization filters
- Damping filters
- Blend filters (750mHz and 250mHz with T240 or not)
- Isolation filters (UGF 15Hz)

Isolation filters were engaged and decent isolation performances were obtained (similar to OAT).

HEPI (BSC6)
The HEPI pump was restarted on April 26^th and the STS-2 can now be centered via the binary outputs. A set of transfer functions was measured.  Filters were refreshed and tweaked with the new version of the scripts. The new filters are installed on the front end.