On Monday, old HAM6 OMC path septum window was uninstalled. We measured the wedge angle of that window using a laser pointer in the optics lab.

See attached for the setup. We used an eye safe lasr pointer that passed Peter King's inspection in the optics lab. We were clearly able to see the direct transmission and the first ghost beam, so we just measured the distance between these two beams at two different locations, and derived the relative angle between these two beams, from which we calculated the wedge angle.

The result is w=0.745+-0.022 deg.

See the attached comments for the details of the measurement and the calculation.

The spec is 0.75+-0.02 deg (D1101005) so this seems to be as per spec after all, despite that in the past we believed this to be more like 0.9 deg. (See the history comment attached to this one.)

Oh, and we confirmed that the mark on the flange was on the thickest side, as per the drawings D1101092 and D1101005.

{Chub, Jordan}

Removed all but four bolts from 84" doors on HAM 11, 12 in H2 volume, in preparation for door removal. Purge air is flowing through the cracks.

{Chub, Jordan}

H2 VE is slowly fading. Chub and Jordan decoupled the turbo station near GV4 and removed its large bellows, six way cross, and other components to make it ready to pick with crane after the H2/biergarten portion mezzanine is removed.

Sheila, Nutsinee

To prep for tomorrow beam check we made sure we could lock OPO on double resonance and see the bright seed beam transmitted onto the SQZT6. We aligned the VOPO platform and ZM1, cranked up OPO gain to 15dB (was -17) and reduced the pump light trigger level. All the working value for OPO in-air lock is now in guardian, simply request LOCKED_SEED_HIGH on the SQZ_OPO guardian when we are ready to go tomorrow.

Chandra, Kyle, Dave:

After the MX gatevalves were closed this morning, the pressure in the X1 beam tube (Corner Station to MX) has been steadily rising as anticipated. The MX end exceeded its alarm point of 5.0e-09Torr several hours ago followed by the CS end an hour later.

Chandra has requested that the alarm level for these two gauge readings be increased to 1.0e-08Torr. I have made this change and restarted the alarm system

-<Channel name="H0:VAC-LX_X4_PT144B_PRESS_TORR" low="1.0e-10" high="5.0e-09" description="VE gauge, LX X1-beamtube, CC">
+<Channel name="H0:VAC-LX_X4_PT144B_PRESS_TORR" low="1.0e-10" high="1.0e-08" description="VE gauge, LX X1-beamtube, CC">

-<Channel name="H0:VAC-MX_X1_PT343B_PRESS_TORR" low="1.0e-10" high="5.0e-09" description="VE gauge, MX X1-beamtube, CC">
+<Channel name="H0:VAC-MX_X1_PT343B_PRESS_TORR" low="1.0e-10" high="1.0e-08" description="VE gauge, MX X1-beamtube, CC">

Chandra also requested that the alarm bypass on HAM6 be extended through to the end of next week

Bypass will expire:
Fri Oct 18 15:26:34 PDT 2019
For channel(s):
    H0:VAC-LX_Y0_PT110_MOD1_PRESS_TORR

Daniel, Nutsinee

Yesterday we did a series of lightbulb measurement with several squeezer diodes used in OPO, CLF, SHG, and TTFSS loop. The diodes used are as follow:

SHG diode has an RF amplifier ZFL-500LN+ (27dB gain) attached and gain a factor of 10 from the mad box gain switch.

CLF diode also has ZFL-500LN+ attached. This is the modified diode from alog47222

The SHG, OPO, and CLF diode spectrum was measured at the IMON (QMON for CLF) output. The IQ demod board gain of 5 has been included. The RF sideband folding factor of sqrt(2) has been included in OPO calculation only (high modulation depth for 80MHz sidebands). 

TTFSS New Focus 1611 Agilent spectrum came from the output of TTFSS pre-amp board. Using the pre-amp gain of 8 (+18dB) the calculated transimpedance is 720Ohms (D1700324). The spec sheet claims 700Ohms. Not bad. The measurement came in dBm/Hz. I converted dBm to V^2 using:

P(dBm) = 10log10(V^2/(R*p0))

;R = 50Ohms and p0 is a reference power 1mW

Then I sqrt(V^2/Hz) to get V/sqrt(Hz)

Putting everything in one place for a future reference.

TITLE: 10/09 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC

STATE of H1: Planned Engineering

INCOMING OPERATOR: None

SHIFT SUMMARY:

I spelled Ed off at 10am & Patrick came in starting at 11am.  Below are activities I noted while I was in the chair.

LOG:

• Corey spelling Ed at 17:00utc (10am).
• MX Scaffolding continues (Bubba)
• 15:30 - 17:13 HAM11 & 12 bolt removal (Chubb & Jordan)
• 17:32 Out to MX for GV work, WP8405 (Chandra)
  • This is on hold until scaffolding complete.
• 17:38 Out to mids & ends for fire panel checks (Fil)
• 17:38 Cleanroom measurements in LVEA (Christina, Vanessa)
• 17:41 SRM going to ALIGNED state (Rahul, Betsy)
• 17:53 Ncal drilling at EX (Rick,Timesh)
• 17:54 Turbo stand work at corner station (chandra, chubb, jordan)

Topped off Crystal Chiller with 125mL.  Diode Chiller OK.  
Filters look fine (mentioned slight yellow tint of Crystal filter to Jeff B & he said it is OK).

TITLE: 10/09 Day Shift: 15:00-23:00 UTC (08:00-16:00 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: Patrick
CURRENT ENVIRONMENT:
    SEI_CONF state: SC_OFF_NOBRSXY
    Wind: 13mph Gusts, 10mph 5min avg
    Primary useism: 0.05 μm/s
    Secondary useism: 0.21 μm/s
QUICK SUMMARY:

HAM6 standown still in effect - All Day

Proposed to Betsy and Keita the option of leaving the QDP80 roughing pump valved in overnight to gain headway on pump down (pressure currently at 30 Torr at BSC2 and 20 Torr at pump station). We typically don't pump overnight because of potential risk of backstreaming into main volume if a pump + interlocked valve fails. After some thoughtful discussion we decided it is not worth the risk and will resume per standard procedure and rough during "business hours" when a vacuum person is onsite to monitor and react in case of emergency. HAM6 in-chamber activities will be pushed back as a result, but schedule allows for this. QDP80 is valved out for the night.

The good news is when the new roughing pumps are operational, we will have a second interlocked valve for redundant protection in order to pump overnight.

Chandra R., Chub, Jordan, Kyle

The XBM Turbo Station is now installed.  Chandra, Chub and Jordan had already removed the iLIGO MTP yesterday and positionined the new Turbo Station.  Toward the end of the initialial flanging of the new Turbo Station to the 10" gate valve, Chub had percieved a problem with one of the threaded studs.  This issue required a deflanging.  In fact, one of the threaded blind holes was damaged and had to be partially rethreaded using a tap.  Following this repair, we reflanged this joint, powered the control panel and spun up the turbo.  Next, the new CFF joints were helium leak tested (helium background/baseline 1.9 x 10-9 torr*L/sec) and no leaks were found.  We are leaving the turbo spinning overnight without water cooling (backed by the LD).  As left, the indicated pump temperature was 24C and the electronics 44C. 

{Kyle, Chandra}

Leak checked flange of new PT180 gauge with background of 1.5e-9 mbar-L/s at leak detector. Sprayed helium for several minutes; no leaks.

Ground loop checks for SUS HAM6 complete.

Same issues with ZM1 and VOPO as seen in last November's vent, alog 45409.

HAM6:
ZM1 (Cable label SUS_SQZ-20) Pin 2 shorted to ground
VOPO (Cable label SUS_SQZ-2) Pin 13 shorted to ground

List of cables tested:

H1:SUS_10 (OMC), H1:SUS_11 (OMC), H1:ISC_236, H1:ISC_237, H1:ISC_238, H1:SQZ_1, H1:SQZ_2, H1:SQZ_20, H1:SQZ_21, and H1:SQZ_30.

C. Gray, G. Moreno, T. Sadecki, B. Weaver

Install of the new yawed septum viewport in HAM 6 went very smoothly today.  We utilized 2 of the aligment pins (3/8-16 silver plated screws with the heads lathed down to thread diameter) that Tyler made for us.  This made the installation much easier as we had something to take the weight of the 22 kg viewport assembly while installing the mounting flange screws.  The septum window accelerometer was reinstalled in the same location it was removed from.  First Contact was removed from the inner, HAM 5 side prior to installation, and the outer, HAM 6 side was removed in-chamber after installation and torquing.  The center of the viewport aperture was inspected and was deemed free from egregious amounts of particles.  

On a related note, this was the first time I had the chance to use the new modular stair system around the HEPIs and can attest that they work much better than the previous iterations of HAM chamber stairs.  

Photos to follow.