PSL trip

The laser shut off last night around 6 pm. It looks like this was due to low water flow through laser head 4. PSL_TRIP_1 shows this shutdown. Channel HEAD4FLOW drops to 0.45 lpm and the interlock trips at this point. The time scale for this plot is 20 seconds.

I turned the laser back on but before I could leave the laser room it shut off again for the same reason. PSL_TRIP_2 shows the trip, as the flow through head 4 drops and trips the interlock. I'm not sure what the threshold here is but it must be around 0.45 lpm. I turned the laser back and and increased the flow through the crystal chiller from 17.6 lpm to 18.2 lpm to try and give some more head room for the flow sensor, but it did not have much of an effect. The flow sensors have always had some erratic behavior, as you can see in the 2 week plot attached. LLO found the filters in their laser heads were quite dirty, so maybe we are starting to see the effect of particle buildup.

Updated ODC EPICS and safe.snap files for SUS, ISI, HPI

I have updated the ODC EPICS settings for all SUS, ISI and HPI ODC channels.

I have also updated the safe.snap files containing these EPICS records, so that they are correctly set on reboots.  The attached files contain the list of changes made to the safe.snap files (nothing listed in the changes_*.txt file under the snap file name means no changes were made), and the modified files have been committed to the SVN.

QPD Transimpedance Amplifier D1002481

Whitening filters for the ISC Dual QPD Transimpedance Amplifier were enabled for the following units:
D1002481-S1102815 - Corner Station
D1002481-S1102811 - EY

R1, a 200 ohm resistor, was reinstalled for each channel to enable the whitening filter.

ISI BS and ITMY DAQ INI files modified, DAQ restarted

Vincent and Dave.

Vincent made a temporary change to the DAQ fast INI files for h1isibs and h1isiitmy and performed a 'daq reload' on these front ends. We then restarted the DAQ at 11:21 with no problems.

EX TMS Work Yesterday

(Corey, Virginio)

Continue to build up the Telescope and In-Vac ISC Table assemblies.

Spent time contemplating how to make TMS Assy Loads in ICS.

Topic of humidity came up in the Weekly TMS Meeting came up yesterday---namely the negative effects of humidity on Optic coatings.  We have a Dust Monitor in the Lab, but it isn't "online".  (For a "first Humidity data point", had a humidity of 21% mid-afternoon time yesterday)  In the future, we'll be receiving desicant packs from CIT and will make "Ameristat bags/covers" for our assys with optics and place desicant within these "bags".

Lisa has completed cleaning of all 2" optics which go on the In-Vac Table.  We will gather opto-mechanical hardware for these optics & then transport this to EX.

Continue to add photos of progress here.

plots of dust counts

Attached are plots of dust counts requested from 5 PM June 18 to 5 PM June 19.

plots of dust counts

Attached are plots of dust counts requested from 5 PM June 17 to 5 PM June 18.

ODC status update

Following Ryan's recent odc label update, the "damp" ODC bit has been updated for MC1 MC2 MC3 PRM PR2 PR3 ETMY ITMY BS SRM SR2 SR3, and is now properly working (cf exemple on picture attached)

In order to do that, I set every suspensions in their "damped state", and ran the attached bash script to update the "STATE_GOOD" epic value "H1:SUS-${OPTIC}_${MASS}_DAMP_${DOF}_STATE_GOOD", with the "STATE_NOW" epic value "H1:SUS-${OPTIC}_${MASS}_DAMP_${DOF}_STATE_NOW".

The "damp" bit (here, BIT 6 on the picture) is ONLY a function of the filters engaged in the damping filterbank. It won't turn red when a gain is changed for instance.

Ear bonding commencing on new PUM-ITM06

Gerardo and Gerardo Jr. have launched the processing of another PUM - today, a fresh ear was sucessfully silicate bonded to PUM labeled ITM06. 

 

Note the PUMS are labeled as ETMs or ITMs, but functionally they can serve as PUMs for either type of QUAD suspensions.

PUM

Mark B. and Gerardo

(This alog is based on final numbers from Gerardo - a typo was discovered in one of the ear positions used in discussions yesterday.) 

The PUM "ETM04" had been selected for use in the ETMx quad at LHO. While reviewing its history in preparation for welding, Betsy, Gerardo and Angus discovered that one ear, on the S4 surface, had been flagged as 0.18 mm from the front-back centerline, outside the 0.1 mm tolerance. (It was one of the first to have ears bonded, before the procedure had been entirely perfected.) Even a small front-back error produces a large pitch torque from the weight of the test mass below, which can produce a significant static pitch in the final suspended chain. 

The positions of the ears and prisms are as in the first attachment. The prism on the S4 surface is at -0.07 mm, which adds to the pitch torque. The ear and and prism on the S3 surface are at 0.04 mm, which subtracts a small net torque. The net expected pitch imbalance is per the second attachment: 4.3, 5.4, 3.2 and 2.3 mrad at the various masses, from the bottom up.

The average misposition of the ears is (0.18+0.04)/2 = +0.11 mm. Since it is not possible to remove and reposition the ears after several years of curing of the bonds, to salvage the mass requires moving the prisms to an average position of +0.055 mm (the weighting of the prisms is -2 that of the ears because the tension on the associated wires is double, and upwards rather than downwards). Since removing prisms is time-consuming and slightly risky, it is preferable to move just one if possible. The easiest possibility is to move the S4 prism from -0.07 mm to +0.07 mm, so that the average is (0.07+0.04)/2 = +0.055 mm as desired. This means that the PUM will sit at a yaw angle set by the prisms of (0.07-0.04)/326.5 = 0.09 mrad, and the test mass will be a yaw angle set by the S4 ear and prism of (0.18-0.07)/326.5 = 0.34 mrad. These are small enough to be easily trimmed statically and should have a negligible effect on the dynamics. (A comparison of TFs with and without the misposition and fix will be posted as a comment.)

However this moving of the prism can't be done in time to use the assembled welding crew in the next few days, so PUM "ETM03" has been prepared and allocated to LHO ETMx (per alog 6800), and, assuming a quick and successful rework, "ETM04" will be used next up as ETMx at LLO in a few weeks.

ETMY pitch opt lever spectra

Attached a comparison of ETMY pitch optical lever with ISI damped with/without FF01 2 feedforward (HEPI L4C to Stage 1 ISI) engaged on ST1 X-Y-Z

In red : ISI damped, SUS damped filter gain = 1

In green : ISI damped, SUS damped filter gain = 4

In blue : ISI damped + FF, SUS damped filter gain = 3

In pink : ISI damped + FF, SUS damped filter gain = 1

Helium background too high to look for GV6 leak

The helium background as the result of testing GV1's outer bonnet O-ring leak (2 days ago) is 1x10-6 torr*L/sec, i.e. too high to quantify GV6's leak -> The only way to be rid of it is via turbo pumping -> We don't valve-in turbos unattended while open to the BT so we can't pump this out overnight.  Rather, we will valve-in the YBM turbo during business hours over the next few days

Ops Morning Summary

EX--running cable to tms

Barker/Batch:  LSC/ASC Naming problems

EY BSC-ISI measurement:  10:35-11:35am (Vincent)

Arnaud wants to do measurement on ETMy (after Vincent)

Michael R worked on the H1 PSL FSS this morning to help with HIFO Yarm locking.

(Thomas is cover the last 3hrs of my shift---thanks, Tvo!)

The "inicheck" program has been updated

The program "inicheck" (not the RCG perl script) has been updated to perform more strict channel name checking.  Bad combinations of ':', '_', and '-' characters are checked as well as characters outside the range A-Z, 0-9.  For detailed information, see the man page for inicheck.

ALS common mode feed-back, including 4Hz:4kHz boost closed - IR beam stays on top of resonance

(Alexa, Chris, Kiwamu, Lisa, Matt, Stefan)

We successfully handed of the ALS common mode feedback to MCL, including AO path, and engaged the common boost. This kept the IR arm power within about 20% from its max.

The setup for our PLL was as follows:
- SR560 A: gain -2; pole at 300kHz, hooked up to Imonn, feeding back to VCO tuning
- SR560 B: gain: 5; pole 100Hz, hooked up to output of SR560 A, output goes to a gain of 2 analog box, and then to the CM board input 1.

Tricks we used along the way:
 -The MC notch filters were all turned off.
- First was AC-couple the MC_L path and turn on the REFL_SLOW path at low gain. This brings the PLL into its lock range by moving the IMC.
- Next we turn off the MCL path
- Then we increase the ALS_MCL path by a factor of 30, bringing its x-over to about 150Hz. THen we engage a digital LF boost. 
- Next the AO path is turned on until the x-over drops to about 100Hz.
- With the H1:LSC-REFL_SERVO_IN1GAIN at +15dB we engage the analog CM boost filter.


Some gains we used in the final state:
H1:LSC-REFL_SERVO_IN1GAIN 15
H1:LSC-REFL_SERVO_FASTGAIN 0
H1:IMC-REFL_SERVO_IN1GAIN 0
H1:IMC-REFL_SERVO_IN2GAIN 2
H1:IMC-REFL_SERVO_FASTGAIN 0

The scripts that do all the magic, CARM_down and CARM_handoff are in 
/opt/rtcds/userapps/release/als/h1/scripts

more pictures to come...

ETM03 PUM in oven.

As of 4:30 this afternoon, Gerardo and Gerardo Jr. were in the process of loading the replacement PUM into the airbake oven, the last step needed before use in a monolithic suspension. Tomorrow morning it can go to an end station for welding. Knock on wood. Well done powering thru placing 2 prisms and 4 magnet mounts, cure times included, in 2 days, guys.

Great Job Gerardo^2!

Your fast work is really appreciated.  Marty

VCO work

New code was loaded to add an integrator to the low noise VCO which allows the frequency to be be stabilized to a set value. The DC offset slider is used as the actuator. Since the frequency is only read once every second, this is only useful for drift control.

A temporary Agilent frequency counter has been set up in the CER to independently monitor the VCO frequency (ALS DIFF). At first glance the measurements are comparable.

Drift of free running VCO over 15 hours. 

ODC Summary Bits Enabled for all LHO Channels and Remaining ODC Work:

Each ODC channel has a Summary Bit that is used to indicate whether each system is in a nominally good operating state.  This bit is generated by checking that the necessary bits in the ODC channel are ON, as specified by the subsystem commissioners.  With the input from Jeff Kissel and Sebastien Biscans, we have set all of the EPICS variables needed to correctly populate the Summary bits for all active ODC channels in H1.  The EPICS variable Bitmasks are decimal numbers that correspond to a bitmask, where for each bit in the ODC channel that should be on when the system it is characterizing is in a good working state.  Here is an example:
H1:SUS-BS_ODC_COMBINE_ODC_BITMASK = 126
In binary, this is 0111 1110, which indicates that bits 6, 5, 4, 3, 2, and 1 should all be ON when the SUS-BS is operating nominally.  If you are curious what those bits mean, you can do the following:

controls@opsws1:~ 0$ caget H1:SUS-BS_ODC_BIT1
H1:SUS-BS_ODC_BIT1             Master Switch ON/OFF Status
controls@opsws1:~ 0$ caget H1:SUS-BS_ODC_BIT2
H1:SUS-BS_ODC_BIT2             DACKILL Status

These BITMASK EPICS records were set using scripts located in /ligo/home/ryan.fisher, and attached to this entry (with modified file extensions so the alog will post them).

With this completed, the EPICS description strings for the bits set and the MEDM screens reworked, we believe we have most of the active SUS and SEI subsystem ODC channels operational.  

The remaining systems for which ODCs need to be implemented under SUS and SEI are: the HAUX (HAM-Auxilliary) front ends and the HAM-ISI front ends.  The latter should be implemented with the next update from the cds_user_app svn (anticipated Mar 15).

We will be generating new safe.snap files specifically for the updated ODC EPICS settings for all models and sending them to CDS-announce for incorporation into the SVN and live systems.

I added scripts for setting the ODC bit labels and masks in /opt/rtcds/userapps/release/cds/h1/scripts

h1setODCbitmask:    Set ODC bit masks for HPI, ISI and SUS
h1setODCbitstrings: Set ODC bit labels for HPI, ISI and SUS

Missed one file for ISI-HAM bitmasks, it should be attached.

I also placed corrected versions of Stefan's scripts in:
/ligo/home/ryan.fisher/EPICS_Scripts

The equivalent files are attached.

I have added EPICS bit label and bit mask settings for the ODC channels for the seismic systems listed below to the scripts:

/ligo/home/ryan.fisher/EPICS_Scripts/h1setODCbitstrings 
and 
/ligo/home/ryan.fisher/EPICS_Scripts/h1setODCbitmask :

Seismic systems added:

HPI-HAM4
HPI-HAM5
HPI-HAM6
HPI-ITMX
ISI-HAM4
ISI-HAM5
ISI-HAM6
ISI-ITMX

I have also added HPI-ETMX and ISI-ETMX to the script for when/if these are added.

I have run these scripts to re-apply all settings as of GPS: 1055723826