The ALS PLL now locks stably for several minutes by using a modified version of the servo filter.
The bandwidth is about 12.5 kHz and the phase at the UGF is 127 degrees.

Earlier the loop was stable with only a very small gain of the common mode servo board (-47dB). Because of that, the PLL range was insufficient and the lock would brake after few seconds.

To better redistribute the gain, Keita made a small filter with gain of 1 at DC, a pole a 4Hz and a zero a 4kHz inside of a small Pomona box (see attached schematic). This provides a gain of -40dB above 4kHz and so it relieves the attenuation by the common mode board.
Today we connected this filter between the output of the phase-frequency discriminator and the input of the common mode board.
After a bit of tinkering with the common mode board gains and switches, Keita found a stable set of parameters.

Input 1: ENABLED
Input 1 Polarity: ENABLED
Com. Comp: ENABLED
COM. EXC.: ENABLED
Fast: ENABLED
Gain IN1: 0
Gain Fast: -6

The lock now breaks only when the laser temperature drifts out of the PZT range (+/- 15V).
The slow control will have to make up for that. Work is in progress.

Looked at cabling for ISC at End Y. Found following DB37 cables without Pin 19 connected, or connected to cable shield. Modified cables with pin 19 connected on both ends (not to sheild), and shield connected to the backshell on the female side.

H2:ISC-BSC6-20
H2:ISC-BSC6-21
H2:ISC-BSC6-39
H2:ISC-BSC6-40
H2:ISC-BSC6-76
H2:ISC-BSC6-77
H2:ISC-BSC6-78
H2:ISC-BSC6-79
H2:ISC-BSC6-80

Filiberto Clara

The following is a list of work of which I was notified, in no particular order.

Y-End

- Reboot of computers to fix timing error, Jim B.

- Cable work, Filiberto and Rodney

- Viewport location, Cheryl V.

- Many other visitors, but no information about their work

Corner Station

- HAM03 work, Corey and crew, see Corey's entry

Doors locked at 4:20 PM.

HAM6 was placed into a shipping container around January 27th, Corey's alog, and purged with a Nitrogen boil-off from a dewar. To the best of my knowledge it has not been purged since that time. To determine what the humidity levels inside the container were like, a super elaborate no expenses spared contraption was developed to capture the exhaust from the container during the purge (photos attached). Data logging using a testo 645 dew point probe was started as soon as the purge began and ran for about 19 hours (graph attached).

Direct LN2 boil-off read at -48.5 td°C, 9.2 °C; while ambient LVEA readings were at 4.4 td°C, 20.1 °C. Purge rate is ~10 L/m with ~5,442 L of empty volume inside the container. 

(caleb aka "counterweight", corey, ed, mark, randy, stephany)

With the ISI Installation Fixture installed at HAM3 & Lifting Connectors mounted on the HAM-ISI yesterday, today's installation activities started at ~8am.  Yesterday's work and today's were conducted under the expert instruction of Mr. Radkins' updated & redlined ISI Installation Procedure (LIGO-E080012-A-D v3); Hugh added specific notes to procedure from lessons learned from the HAM2 Installation last week.

The Apollo crew craned the ISI with the West crane close to HAM3 (this was done with the pair of 2-legged slings connected to the crane---we didn't want to use the long Installation chain because we wanted clearance to hoist the ISI over BSC chambers).

From here, all went according to procedure.  ISI landed on Cart, to hand off ISI to other crane; ISI attached to Installation fixture; ISI rolled into HAM3.  I wish I took photos of clearances for this move, but we moved too fast and efficiently---main thing:  careful alignment of A-Frames made it easy to slide the ISI into place.  Did not need to move cleanroom for any of this work. 

It should be noted that the ISI did not hang completely level.  One could see with a bubble level that we were slightly off.  This was even more important when the ISI was lowered on to the HAM3 Support Tubes.  For this landing, the SW corner touched down first, and the west side touched down first with the east side high by about 1".  So, it did take some jiggling and vertical cycles to finally start threading all the bolts.  (we also had Caleb put on some In-Chamber boots and stand on our high side of the ISI to help make it level and ease threading the eastern bolts.

Similarly, to HAM2, it was observed that a couple of bolts appeared to have issues with their thread (they'd get bolted down, and when a torque was applied, the bolts just spun in their holes without getting tight).  Ultimately, we replaced the bolts, and the fresh bolts did the trick.  (We went ahead and installed/torqued a new bolt in the missing SW bolt for HAM2 with no problem.)

On the east side, we were not able to install a southeast bolt--it was blocked by a Shipping Bracket.  On the west side, we were not able to install one of the 5" bolts which was below a Vertical Actuator (this bolt also not installed on HAM2).  Other than that, all bolts were torqued down (just need to remember to install that bolt on the east side.)

Here is a link to all photos taken for HAM3 Installation work, here.

Install time:  8 - 11:30am

THREE more to go!

An IRIG-B timing error occurred at about 22:15 UTC June 14, 2012 on all of the front end computers at the Y end station.  This went unnoticed until this morning.  I have corrected the problem by restarting the models on the following computers:

h2pemey
h2susauxb6
h2tcsey
h2pemeyaux

Note that the remaining two computers, h2susb6 and h2seib6 were restarted late yesterday afternoon to correct what appeared to be a RFM error, so the IRIG-B time was reset then.

Models affected:

h2pemey
h2iscey
h2susauxb6
h2tcsetmy
h2pemeyaux
and the IOP models for the computers.

Work completed at 17:45 UTC June 15.

Matt Evans noticed that I had screwed up the time between the start of the BSC8 curve and the initial pump down
it is 5.9 days. This makes the BSC8 curve the same as the initial LIGO pumpdowns. It still leaves us with the problem
of what to do about BSC6 with its more gradual slope and factor of a little over two higher pressure.

The figure shows a revised version of the pumpdown curves. The variation of the pressure with time for BSC 6 is still
slower than 1/t. A least squares fit to the curve gives a dependence of 1/t^0.865 which as indicated before implies some diffusion
of water from inside of materials, the phenomena is not just desorption from the surface. The plastic in the cables or the viton could be 
the source. The pumpdown curve for BSC8 is the first formal continuous pumping of this chamber which occured about 20 days after the initial
roughing. John Worden made a time line graph of the various conditions of BSC8 in a prior entry. If you are interested in understanding
the reasoning for the curve plotted here look at John's time line. In the initial pumping of this chamber a broken feedthru was discovered 
and replaced. The chamber was being pumped or living in dry backfill gas for those twenty days. For water outgassing from the surface it 
should not make a great deal of difference whether the water is removed by a purge gas or by evaporating into a vacuum. Clearly a vacuum is
better as there is less repopulation of the surface, but the purge works too with some higher probability of repopulating depending
on the remaining humidity in the gas. The conclusion I draw from this is that the BSC6 is not so anomolous and that we will need
to take steps to reduce the water in the ISI for the next installations using techniques such as continuous dry purges in bags around the
ISI with the ability to gain entry for adjustments etc. If we want now to speed up the time to a pressure of 10^-7 torr it would take a
low temperature bake, say to 50C. The danger to the instrument associated with such a bake and schemes for carrying it out are being studied
at the moment.

Attached are plots of dust counts > .5 microns.

At about 15:50 the IOP watchdog on h2seib6 tripped due to bad packets on the RFM coming from h2susb6. All RFM cards, switch ports looked good. We worked on the h2seib6 first, swaping fiber with pem, reseating the card.

The we power cycled h2susb6 and the problem cleared. All systems are back online.

I verified the location of viewports on the A-17B adaptor, and compared those positions to the stated plan in T1000746-v5, and found that the most likely viewport position (VP5) to use for the video camera, has a blank on it.  See attached file.

As you know, we are transitioning to a new garb laundry vendor, Prudential Cleanroom Services. Prudential's protocols call for footwear that comes in contact with the floor to be washed separately from other garb. In our case, that means shoe covers and boots. To facilitate this practice, I will be placing appropriately marked bins in the change/garbing rooms tomorrow. In addition, Prudential has agreed to process our in-chamber boots separate from all other footwear and garb. To facilitate this practice, I will be placing appropriately marked bins in applicable situations tomorrow. To keep in-chamber boots as clean as possible, please remove them at the door upon exiting a chamber.  DO NOT WALK ON THE FLOOR when wearing in-chamber boots. 

Staging was completed around the chambers and the north doors were removed from both chambers. The dust barrier was prepared for installation at the Mode Cleaner tube attached to HAM5. 

(corey, Apollo Crew:  Mark, Randy, Ed, Scotty, Caleb)

After the cleaning crew finished HAM3, Apollo started taking doors off (before lunch).  After this, the crew started headlong with installing the ISI Installation fixture.  Much more care was taken with positioning these parts due to fit issues discovered with HAM2 install.  Mark mentioned being within a few sixteenth's for all the major interference points (i.e. HEPI Spring Cyllinders & HAM Chamber).

The large flange will be removed on top of the chamber.

The ISI is staged and ready to go (all lifting connectors are torqued on table & chain slings are attached to them).  First thing in the morning, Apollo will hoist the ISI into position just outside of HAM3.  We will then install the ISI.

BSC6 curves from cartridge install.  +data file in .txt format.

Summary: Results from wiping experiments are consistent with the hypothesis that the black residue is brushing residue that has not been cleaned off by the wiping procedure because it has collected in scratches and crevices that are not reached by the stiff wipes. It comes off on latex gloves because they are less-stiff and can access those crevices. To avoid transferring the black residue from the walls to the optics, we could re-wipe the chambers with less stiff wipes, or we could instead use gloves made of a stiffer material than latex that doesn’t deform into the crevices that contain the residue and pick it up when a gloved hand touches the wall. Jodi will plan on trying nylon, nitrile, and co-polymer clean room gloves.

Jodi told me that that the black residue found after chamber cleaning (described here) does not require time to develop but instead blackens latex gloves immediately after chamber cleaning, even though it does not come off on the synthetic wipes that are used to evaluate chamber cleaning. This suggests that slow re-oxidation is not involved.

BSC3 was cleaned about a month ago, so I did a little study to see what wiped up the black residue and if the residue could be removed. Just as Jodi described, I found that a normal rub with the synthetic wipes we use to clean the chambers produced no black, but that the slightest rub with a latex glove immediately blackened the glove. I then found that I could get black on the wipes with a really forceful rub: as hard as I could press with an area of just one finger (see figure). I found that I could get black smudges with forceful rubbing of bunny suit material, in-chamber booties, and face masks, but nothing was as easy as getting smudges on the latex gloves.

I then checked to see if I could clean the black residue off of the wall so that there was no more that came off on latex gloves. To do this I rubbed a section of wall about 20 times with latex gloves. The figure shows that this worked well, resulting in no smudges on the test glove.

Thus our best hypothesis is that the black material is residue from brushing that collects in regions that are difficult to access with the normal wipes. A wipe that conforms more to the surface topography, such as latex, would remove more of the residue.

My biggest worry associated with the black residue (other than that the extra surface area may require longer pumping) is that we will transfer it from gloves to optics. We could mitigate this danger by re-wiping the walls with a less stiff wipe, or, less costly, by using gloves that were stiffer, e.g. made of the same materials as the booties, bunny suits, or wipes. For a start we could try knit filament nylon, nitrile or co-polymer clean room gloves.

Robert, Jodi

MC2 Metal Build OLVs measured

BOSEMs

s/n 092, OLV 27702.4 (T1)

s/n 043, OLV 22923.7 (T2) 

s/n 030, OLV 28098.7 (T3)

s/n 023, OLV 26766.2 (LF)

s/n 086, OLV 27693.4 (RT)

s/n 613, 30169.8 (SIDE) Characterized one

AOSEMs

M2

s/n 307, OLV 24825 (M2 UL)

s/n 474, OLV 24060 (M2 LL)

s/n 439, OLV 24304 (M2 UR)

s/n 305, OLV 25954 (M2 LR)

M3

s/n 207, OLV 24822 (M3 UL)

s/n 311, OLV 23630 (M3 LL)

s/n 446, OLV 26177 (M3 UR)

s/n 188, OLV 16687 (M3 LR)