This is a 2 hours trend when the end PDH signal was offloaded to the BSC6 HEPI yesterday (see alog 6862).

This worked good so far --- the end laser stayed locked for more than an hour without an obvious sign of misalginment.

Although we do see drift in the ETMY oplev signal as the amount of the offload increases. Since the alignment of the arm stayed good, this could be a longitudinal to angle coupling of the oplev itself.

The TMTS_MASTER.mdl has long had an error whereby the slow channel giving the text label for BIT4 of the ODC word was called H1:SUS-TMSY_ODC_BIT6 or the like. This caused the text field opposite BIT4 in the SUS_CUST_TMTS_ODC.adl screen to show white.

I fixed the master model and rebuilt and restarted h1sustmsy. I also manually edited the safe.snap file, changing _BIT6 to _BIT4, and confirmed that the old BIT6 value was being correctly applied to BIT4 on a BURT restore.

I committed the new master model and the new safe.snap file. Although the change didn't involve any channels being written to disk, David Barker restarted the DAQ as a precaution.

LLO should also apply this fix. Any scripts that initialize the ODC bit labels should be rewritten to no longer work around the error.

This is the current setup for our PLL-based frequency sensor and this reads out the beatnote of the green light at the vertex serving as a CARM sensor currently.

Here is a measured open loop transfer function of the PLL :

Some parameters and notes:

• UGF is at 60 kHz
• VCO DC response was measured to be 285220 Hz/V by a measurement with the IFR signal generator
• PFD coefficient was found to be 45 deg/V according to my eyeball fitting
• The was a phase lag which can be modeled by a delay of ~ 1.5 usec.
• The in-loop SR560 has
  • gain = 5, pole 300 kHz and another pole at 300 kHz
• The out-of-loop SR560 has
  • gain =10, pole at 100 Hz

These model parameters were used for calibrating  the analog CARM signal described in the previous alog (see alog 6878).The raw data is also attached.

One concern we had in the last CARM in-loop noise spectrum (see alog 6859) was that there might be more noise at high frequencies in which the digital system is normally unable to monitor. To check the high frequency situation I took a new CARM spectrum at the floor with an SR785 up to 100 kHz.

It looks like there is lots of noise at high frequncies mainly above 1 kHz. They are not identified yet at this moment. The plot is shown below.

The red curve is the one I newly took with the SR785 -- it matches with the previous measurement shown in cyan at around 2-5 kHz, indicating the calbiration of the analog signal is about correct. The cyan curve goes down rapidly above 5 kHz due to probabaly a down sampling filter. A huge peak in the red curve is located to be at 37 kHz corresponding to the FSR of the arm cavity. As for calibrating the analog signal I corrected the loop surpression of the PLL so that the plot should be valid even if it is above the UGF of the PLL which is at 60 kHz. The raw data is attached.

re WP 3999

We swapped the Parker Valve on BSC2 NE Vertical Actuator.  It went smoothly with little mess.  This Vertical Actuator remains in bleed mode for a time, at least an hour or several.  This means vertical drive of this corner is not possible.  If the HIFOY crew can not proceed come early afternoon, we'll forgo any further bleeding and put it back to Run mode for driving.  Otherwise we'll put it back into Run mode first thing tomorrow.  At the moment this disturbed position is not critical for the HIFO crew.  Attached are trends of the global position, it sure would be nice if the frames had the units contained...  I believe the units presented are nanometers & nanoradians.  So the horizontal positions are back: X, Y, & RZ; but, the vertical dofs are not.  Again though, currently, the HIFOY crew can work with it the way it sits.  If you think about the location of the corner we have disturbed, it's likely we have tilted the table around the barrel of the optic and therefore possibly have only rolled it.  Looking directly at the vertical IPS readouts of corners 2 & 4, (not plotted) there is a total pitch about the NW-SE axis of 1.5mm over the ~4m distance between the diagonal piers giving a roll of ~0.4mrads.

Noticed pressure increase on X-arm this morning -> Found that one channel of IP10 had shut off -> Turned channel back on and OK now -> Took this opportunity to change "STEP" values from 7000V-5000V-3000V to 5000V-5000V-3000V 

h1fw0 is currently offline for its upgrade, adding a local RAID storage device for raw minute trend archival. This means that h1nds0 does not have access to recent frame files. Most NDS clients are defaulting to h1nds1 and will not be impacted by this work. If you are using h1nds0, please switch to h1nds1 for the duration of this work.

[Matt, Lisa, Chris, Kiwamu, Alexa]

(This alog pertains to work done last night).

Last night we went to EY and adjusted several settings in both the PLL and PDH loops.

PLL LOOP:

We changed the settings on CMB_FIBR to increase the UGF of the loop. In particular, we turned off the output gain and decreased the input gain to -6dB. In addition, we turned the generic filter on. The settings are now as follows:

Common Compensation: ON

Boost one:  ON

Fast Option: ON

Generfic filter (in common path): ON

Input gain: -6dB

With these settings, the UGF is now 29kHz (up from 20kHz). We also measured the error signal spectrum and saw a peak at 28kHz.

PDH LOOP:

We also made changes on CMB_REFL. In particular we increased the input gain to 12dB. The settings are now as follows:

Common Compensation: ON

Boost one: ON

Input gain: 12dB

Output gain: 0dB

In addition, we altered the temperature control to reduce oscillations of the signal; on the PLL autolocker we reduced the slow frequency servo UGF to 0.01 from 0.035. We also tried using a 4dB attenuator on the RF modulator to see if that would reduce the oscillations; however, this did not seem to help.

With these settings, the UGF is now around 3kHz (down from 9kHz). Again, we measured the error signal spectrum and saw a peak at 28kHz. Clearly, we were seeing the features of the PLL loop in the PDH loop.

Additionaly, we saw that H1:ALS-Y_REFL_A_DC_POWER was oscillating vary rapidly from 50 counts to zero counts. As we misaligned the PD, the oscillation continued but reduced to 20 counts. If we completely blocked the beam, the signal dropped down to zero counts and remained so. As of last night, we left the PD slightly misaligned to reduce the oscillations in the PDH loop.

Attachments:

The attached pictures are as follows:

1) PLL transfer function

2) PLL error signal spectrum

3) PDH transfer function

4) PDH error signal spectrum

5) CMB_FIBR (as of this morning)

6) CMB_REFL (as of this morning)

(Corey, Keita, Lisa, Matt, Virginio)

In-Vacuum ISC Table

Lisa & Matt finished up laying out optics on the table (this included installing the mirror on the Beam Diverter, and installing the High Power Beam Dump [although one of the ceramic legs broke & will need to be replaced]).  This afternoon they were approaching point of aligning optics.

Setting Up Alignment Laser & Telescope Work

Virginio & Keita worked on setting up the alignment laser.  Before using it, they wanted to measure the beam profile of the laser.  The Telescope Assy was suspended from its tooling.  Made an Ameristat "tent" to enclose the Telescope and the Ag-plated mirrors when they are ready to be installed.  The mirrors will be insalled when the desiccant packs arrive on site. 

Clean Up, ISC-ing, Photos, Feedthru, & Humidity

Continued putting hardware away, and working on making ICS Assy Loads for the TMS.  Continue to upload photos of progress, here.  Helped Filiberto install the final roof-side cable to the TMS feed-thru.  The humidity in the Lab was 34-40%.

Filiburto DC powered the IO Chassis for h1iscex, Jim and I started the IOP model. We found that the IO Chassis appears to be the PEM MY (one ADC, one 18bit DAC) rather than the ISC EX Chassis (3 ADC, one 16bit DAC). 

• Corey and Virginio at EX working in TMS lab
• Filiberto hooking up cables at EX
• Jim Batch at EX troubleshooting network issues
• Gregorio at MX dropping off parts for iLIGO PSL
• Dominick at MY storing parts for Filiberto
• Rick, Craig, Pablo, Colin in H2 PSL assembling PCAL periscope

Last shift at LIGO. It's been fun!

Valved-in YBM turbo @ 0930 hrs -> 6.5 x 10-7 torr*L/sec

Valved-out YBM turbo @ 1600 hrs. -> 4.3 x 10-7 torr*L/sec

Just before lunch, I moved, unplugged and replugged back in the dust monitor at X-end.  It had been sitting in the large cleanroom over the chamber, but since the the chamber is closed with the hard-covers, the more fitting place is for it to monitor near the ETMx optic.  So, it is now in the cartridge assembly cleanroom.

Following the activation of jumbo frames on the EX DAQ switch, the IOP models h1iopsusex, h1iopsusauxex and h1iopseiex were successfully started with no negative impact on the DAQ system. The IO Chassis for h1iscex is not connected or powered, and so that front end is not running at the moment.

Here is the current status of the aLIGO SEI work regarding the HAM chambers. Everything in bold is to be completed for HIFO-Y. Everything in red is a change from last week's status. Everything in green is available.

Here is a plot from last night showing the VCO stability using the slow servo to keep it at nominal. 
The standard deviation of the distribution is about 16Hz.

None of the end-x front end computers had correct BIOS settings, so all have been changed to disable as many "features" as possible, and to enable PXE boot option ROM loading.  New BIOS settings resemble those of h1susb123 in the BIOS settings document (T-1300536).

HAM HEPIs 4 and 5 were brought into run mode yesterday, June 20th. 

current HEPI Status: