Summary

Whatever happened to IM1, Rahul did make it better again. Reasons for improvement is unknown but we proceeded with the alignment and we're mostly done.

There is a mystery scattering or maybe clipping somewhere close to the IFI output but not on the output baffle nor DKDP baffle. It could be a scatter from the CWP surface, or a ghost beam somewhere, or something else. It will take a LONG time to diagnose this, and quite likely this existed for a long time. I'm tempted to leave it at this time. But I'll try to take some more pictures.

There's also something weird about the 1st pico mirror PIT actuator for ISS array.

We'd still like to take pictures/measurements here and there on Tuesday.

Done: ASC REFL centering

Following the morning work (alog 90525), REFL ASC censors were centered using RM1 and RM2. About ~30% of DAC range was used for RM2 (RMs_happy_again.png). FYI, using flash peak, [P,Y]=[-0.003, 0.015] for REFL_A and [-0.020, 0.001] for REFL_B. (Doesn't matter how close these are to zero as far as they're within +-0.1 or so and the SUM is decent, but it feels better to be able to get close to zero.)

Done: ISS array centering

Then we looked at the ISS array and the QPD was not centered. A quick adjustment of the second pico that is closer to the array was all it needed (keita_ISS_happy1.png). [P, Y]=[-0.03, 0.05].

Done: IFO REFL baffle (HA13) adjustment

We looked at the IFO REFL baffle (HA13) in front of the HAM2-HAM3 septum window and it was too high even though it was not clipping, so we lowered it by a couple mm. Before: lower edge height = 105.5mm; upper edge = 206.8mm. After: lower edge = 103.6mm; upper edge = 204.5mm.

This baffle was already moved by a couple mm in +Y direction last week (because the beam was closer to +Y edge). See  IFOREFL_baffle_before_relocation.jpg and IFOREFL_baffle_after_relocation.jpg though it might be difficult to see the difference from this picture.

IFO REFL beam looked like IFOREFL_HA13_baffle_after.mov after the height adjustment.

Mystery flashes seen inside IFI output baffle aperture

We proceeded to check the IFI output baffle and I was bothered to find that something that looked like clipping was visible close to the left edge of the baffle using the IR camera. See IFI_OUT_clipped_720p.mov, this is a view from +Y door. But this was less frequent than the flashing itself. In a retrospect, this was probably the reflection from the PRM when the beam was swinging to the left of the video, but anyway we did various things:

• We got suspicious about PRM somehow misaligned, checked it on the retroreflection check iris but it was fine in YAW (it was off in PIT so changed PIT offset from -1185 to -1115, not sure if it was PRM that changed or something else, but the important thing was that it wasn't off in YAW and that this is not something that I worry about now that we have a decent headroom for RM2 DAC).
• We closed the HAM3 door cover (which did quiet down the beam motion a lot) as well as the HAM2 -Y door cover. I used IR viewer and thought that nothing changed at the time. The bright thing didn't disappear after blocking the beam between PRM and IM4, again using the IR viewer, I thought.
• However, revieweing videos shot later, I haven't found anything to the left of the output baffle after the beam motion was reduced by closing unnecessary open door covers. But that revealed the next issue.

See IFI_out_another_view.mov, this is after the beam quieted down enough and after PRM PIT was changed. The bright thing at the left side of the baffle hole is not visible any more, but you can still see bright-ish scattering of some sort inside the baffle aperture which was there even when Rahul blocked the beam between PRM and IM4. IFI_out_another_view.jpg shows the same thing but with more useful exposure. This is concerning.

DKDP baffle behind the IFI output cwp baffle looked OK (IFI_DKDP_baffle.mp4). BTW, as was reported before, it looked to us that the IFI output baffle has an offset in -X+Y direction relative to DKDP. In the video, the beam on DKDP is slightly biased to the right on average because we tried to split the difference between two baffles.

We moved IM1 in YAW by +-200urad while observing the IFI output by IR viewer to see if there is a better beam position on IFI output. It seemed to me that actually we don't have much space here.

Look at IFI.png to see how the beam is routed through DKDP, output CWP and then passes by the parking beam dump pick-off.

• If we give negative 200urad for IM1 YAW, the forward-going beam starts to interfere with the parking beam dump pick-off once in a while and the frosted barrel of that pick-off becomes bright. This is despite that the beam looks perfectly fine when IM1 is at the now-nominal position (see parkingBD_pickoff.mov, negative 200urad IM1 rotation would mean that the beam will be like 1mm to the right in this video).
• If we give positive 200urad for IM1 YAW, I thought that +X side of the IFI output cwp baffle starts to get brighter once in a while (my theory is that this is the same thing as shown in IFI_OUT_clipped_720p.mov where the edge of the baffle clips the back-propagating beam when the beam moves too much). 

We'll be better once we're in vacuum because things will be quieter and the MC alignment will be better, so no beam motion and no HOM transmission, but I have to say that the clearance here looks to be unnecessarily narrow. I will NOT touch IFI itself so the only option for mitigation will be to move the parking BD pickoff, but it will be tedious to align that pickoff to steer the beam into the beam dump on top of HAM2. Given the limited time available I'll leave it as is.

We don't know what this scattering is, maybe it's the AR reflection of CWP or DKDP hitting something, maybe it's the surface scatter of CWP. I'll try to take the video from the back of the IFI output beamdump/CWP using a big inspection mirror.

Done: IM4 TRANS centering.

Rahul used pico mirror to roughly center IM4 TRANS while I was monitoring individual segments.

Done: IM4 baffle (HA12) moved

As planned. The beam originally was offset in +X direction (IM4_baffle_HA12_before.mov), IM4 baffle was moved a bit in -X direction (IM4_baffle_HA12_after.mov).

Done but not really: Picturing the picos, one concern for the first ISS pico actuator.

Today:

• Jim, Mitchell, and Randy reinstalled the Keel payload (craning it into place up on top of the ISI.
• Jim dropped all 40 cables down from the ISI to the chamber.  He also worked on cabling up the ISI to tidy and add the new stuff more appropriately.
• Tony and Oli embarked on plugging everything back in oer the serial number map in the google doc on D1003079.  They left the white CPS cables for Jim to do.
• Jason and RyanC took the first round of BBSS structure (/ISI) shots, see their alog.  Promising, corroborative results.
• Travis and I reinstalled the Stays and the last Vibration Absorber onto the BBSS structure and re-tightened everything.
• Oli, FIl and I plugged in the Top stage QOSEM cables at the Satellite box, then embarked on a small cable re-understanding regarding M2 and M3.  Fil will move the M2 stage Sat box from R4 to R2 (we had been still needing it there while on the test stand) in the coming day(s).  The QOSEMs seem to have signal in the right places.

Up next:

Start HEPI spring loading, recheck FARO shots, move per what FARO says we need to move

Suspend the BBSS, take Top TFs, then work on M2 and M3 stage OSEMs.

Erik V, Jennie W, Tony S

Summary: Jeff and I need a solution for SPI installation in order to communicate offsite to team members about alignment. Erik and Tony found a solution using the Blueman application. Just now we have this working on 

1. Use the application called 'blueman' on linux (check blueman installed first). Tony is installing this via puppet so it should propagate to all workstations and laptops.
2. Once installed there should be a bluetooth icon in the taskbar on the top right.
3. Right click on this and click 'Turn Bluetooth On'.
4. Then click on 'Make Discoverable'.
5. Click on 'Set Up New Device' on the same menu.
6. In the Pop-up menu find your headphones in the drop-down menu and follow the steps to pair your device while pressing pair on headphones.
7. 'Make Discoverable' may timeout so you need to repeat from step 4.
8. At some point a pop will appear asking for authorisation for the new device, click 'Accept'.

TITLE: 06/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

ISS PD Array alignment continued, ITMy First Contact prep (for 3hr First-Contact-ing tomorrow), some FARO work for BBSS, cabling in BSC2, etc.
LOG:

• 1415-1542 technical cleaning in LVEA (kim)
• 1440-1535 Boxing up BS in West Bay (randy)
• 1517-1550 Check on randy (betsy)
• 1535-1907 Set-up for ITMy First Contacting (anamaria)
• 1539-1616 BS boxing completed (randy)
• 1622-1710 Technical cleaning in lvea cont. (kim)
• 1622-1624 grabbing cds laptop
• 1643-1907 Prep for ITMy First Contact-ing (ibrahim)
• 1705-1754 IM2 check at HAM2 (rahul)
• 1707-1925 HAM7 in-chamber (sheila.begum.camilla)
• 1716-1930 FARO set up @HAM3 (jason.ryanC)
• 1721 Inspection @CEBEX (Aegus truck let in at gate)
• 1723-1840 Craning around bsc2 (randy)
• 1725-1859 BSC2 in-chamber work (betsy)
• 1732-1957 BSC2 in-chamber (oli)
• 1732-1903 Craning stuff around bsc2 (mitch.jim)
  • 1839 Mitch out, 1903 Jim out
• 1736-1957 BSC2 in-chamber (tony)
• 1739-1927 CRS lab work (alex)
• 1745-1751 rga bakeout check + vac walkabout (jordan)
• 1745-1802 garb checks & restarted dustmonitors in mega-cleanroom (kim)
• 1751-1927 CRS lab work (shoshonna)
• 1754 spi cabling (fil.jeff)
  • 1850 jeff out
  • 1856 fil out 
• 1802 cement truck for cebex 
• 1804-1912 Opening lightpipe + JAC table work (jennie.maddi)
• 1805-1813 pump cart check (travis)
• 1808-1845 Back for IM2 checks at HAM2 (rahul)
• 1809 M6.1 Cuba EQ
• 1846-1856 lvea walkabout (richard)
• 2000-2009 Moving laser safety panels to East Bay
• 2009-2020 rga bakeout check + vac walkabout (jordan)
• 2020-2050 Drive to CEBEX & EY (mike)
• 2021 CRS w/ laser hazard late afternoon (shoshonna)
  • 2041 alexandra joining
• 2022 Back to BSC1 for First Contact prep (anamaria)
• 2025-2156 BBSS stay install (betsy.travis)
  • 2143 travis out
• 2025 ISS crew continues (keita.disha.rahul)
• 2026 HAM7 in-chamber & possibly set-up bifurcated area (begum.camilla)
  • 2242 maddi joining
• 2029-2100 HAM3 parts search (jeff)
• 2036-2226 Cable work upstairs at BSC2 (jim)
• 2039-2234 FARO set up @HAM3 (jason.ryanC)
• 2052 ITMy SW watchdog tripped
• 2107-2116 Photos at HAM3 (jeff)
• 2157-2208 Assisting w/ laser curtain set-up in East Bay (travis)
• 2250 Joining CRS (jim)
• 2258 rack checks/work (susr2) [betsy.oli]
• 2326 CER check (dave)

J. Kissel, F. Clara
WP:13296

%%%%%%%%%%%%%%%
Executive Summary: 
Following up after last week's completion of SUS-R2 (LHO:90500), all HAM3 in-air electronics cables and optical fiber patch cords to/from SUS-R2 or TCSY to the chamber have been "pulled," i.e. routed fully to each end of their connections. This leaves *only* the HAM2 ISIJ QPD connection to its transimpedance amplifier in SUS-R1 as the last cable to be landed in the ex-vacuo part of the SPI electronics wiring and optical fiber network.
%%%%%%%%%%%%%%%

Details
Here's the status summary of each of the HAM3 cables and patch cords Fil and I pulled today.

SPI Picomotor Cable SPI_HAM3_013
Description :: This cable connects drive CHs 5, 6, 7, and 8 of the TCSY / CO2Y Picomotor Controller "G" (driven by Corner 2 ECAT Chassis) to the HAM3 D6 12x D25 feedthru into port F11. 

Status :: Now connected at controller and at flange. Strain relief at flange is not yet final.

SPI PD Concentrator Cable SPI_HAM3_015
Description :: This cable bus routes the SPI HAM3 ISIK Transceiver PD and QPD signals (IFO_REF_A, IFO_REF_B, IFO_MEAS_A, FBR_PWRIN_REF, FBR_PWRIN_MEAS, IFO_MEAS_B, QPDB_Q1, QPDB_Q2, QPDB_Q3, QPDB_Q4) from HAM3 D6 port F10 to the "PD Input" port of the S2500712 D1002481-v4 "Variant 2" of the SPI transimpedance amplifier (TIA) chassis in SUS-R2 U4. 

Status :: Now connected at TIA and at flange. Strain relief at flange is not yet final.

SPI_PSL_001 Optical Fiber Patch Cord
Description :: This optical fiber patch cord connects the fiber collimator SPI-FC1 fiber output of the SPI Pick-off Path in the PSL to the "PSL IN" fiber input port on the front-panel of S2500058 D2400156 SPI Laser Prep Chassis in SUS-R2 U6+U7.

Status :: NOT ENERGIZED (thanks to newly installed Uniblitz Shutter; LHO:90490). BUT -- shielded with standard orange protective tubing and now brought down from the cable tray (2nd story of "high" tray running above the input arm) and landed at the Laser Prep Chassis. Neither strain relief nor routing through rack is final.

SPI_REF_001 and SPI_MEAS_001 Optical Fiber Patch Cords
Description :: This pair of optical fiber patch cords connect the modulated at 80.0 MHz [MEAS] and (80.0 MHz - 4096 Hz) = 79.995904 MHz = "80- MHz" [REF] light from the SUS-R2 U6+7 Laser Prep Chassis fiber output ports to the HAM3 D4-1J1 [S3228003 MEAS] and D4-1J2 [S3228002 REF] fiber feedthrus (D2500175).

Status :: NOT ENERGIZED (no laser input from PSL, nor are the AOMs being driven with any RF). BUT -- shielded with standard orange protective tubing and routed in the "low" cable tray system that runs from SUS-R2 to the feedthrus underneath the -X side of the chamber. They're connected at the SUS-R2 U6+7 Laser Prep Chassis fiber output ports, but they're dangling at the feedthru end because we haven't finished upgrading the feedthrus (see LHO:90511).

References
The SPI Pathfinder has been integrated into lots of different subsystems, so there's a ton of disparate systems drawings that are need to follow its signals from "soup to nuts."

Optical Fiber
[1] D1300348 As-built PSL/IO Table Layout
[2] D2400110 Optical Fiber Routing Diagram

RF electronics and PD Electronics
[3] D2400111 SPI Wiring Diagram
[4] D1002874 HAM3 Flange Layout
[5] G2401479 Systems-level Slides for HAM3D4_12xD25 and HAM3D6_FiberFeedthru plans
[6] SUS-R2 Rack Layout w.r.t. SPI
[7] E1100591 (Heliax) RF Signal Distribution System

Picomotor Drive
[8] E1100892 TCS Wiring Diagram
[9] D1900511 ISC Wiring Diagram
[10] D1100683 EtherCAT (Beckhoff) System Diagram
[11] E1200072 Picomotor Channel Inventory [[Very-out-of-date -- see unresolved IIET:32610]]

Shiela, Begum, Camilla

Starting at FC alignment from Friday, 90527.

Tried to make the beam the correct ~5.5” height at ZM2 with A:M1 and then use ZM2 to get correct height at ZM3 (~6.25") but ZM2 did not have enough range. We railed it by only going halfway. Instead, we used A:M3 for beam height at ZM3 and then ZM3 for retroreflected beam. Did this only in PITCH (used YAW offset to help check retro-refection). Took height measurements (~6.25" at FC1 and  ZM3, 5.85") This is not perfect at ZM2 but we'll check for any astigmatism when beam profiling. Attached alignments. 

Tried to use B:M1 and BM4 to realign to ZM4 iris. However, beam could not be near centered on B:L1 aperture and fully transmit SFI2 (was a clipped after SFI2).

Realized beam height wasn’t level after OPO. High at A:L1 and low at A:DC2. We then used A:M1 pitch to center art A:L1 and then SFI1 aperture. And A:M2 to center on A:L2 aperture. We again checked if we could now get the correct height at ZM2 without railing ZM2 to get bean to ZM3, no. So adjusted A:M3 in PIT. After this was done, we realized PIT and YAW must be cross coupled as the beam was yaw'ed towards +X at the ZM3 iris. Paused. 

Ibrahim, Anamaria

This morning we:
-  set up the FC fabric on the drum;
- lowered the ITMX ACB to take its wedge, and then used it to swing the ITMY ACB out of the way;
- inserted the peek "Kurt fingers" between ITMY and its CP in preparation for installing the FC jig this afternoon.

This afternoon we:
- set up the jig around the test mass;
- tightened the drum with the fabric onto the test mass while watching the fibers on camera;
- added the grid+mesh for pressing, as well as picos on the ring of the drum;
- added the funnel and hose setup, connected to the spigot.

We will add more details and photos later. For now we are dumping photos in the common FC google drive. Folders named by date and activity.

First attachment shows that the ISS array PDs suddenly lost the beam (bottom left) right after the IM1 LL OSEM jumped (top left) on Friday, meaning that the problem was not just the OSEM sensing, somehow the alignment was affected by this.

This morning Rahul physically inspected IM1 and checked  cables and electronics but nothing was wrong. He pulled the LL OSEM and nothing was wrong either. He put it back on, centered the OSEM depth (only for LL) and everything looked normal.

We locked JAC and suddenly we got the flashes on ISS array back, see the second attachment.

Though this is good, it's also frustrating that we don't understand what happened. My theory is that somehow something (OSEM bobbin thing?) was charged and pulled the closest metal electrostatically, changing the DC alignment.

We'll  see if we can center REFL ASC sensors as well as ISS QPD. If we can, we'll proceed to close out.

FYI, following is the IM1 OSEMINF before the jump, right after the jump and now. UR experienced 500 counts jump and clearly got back after Rahul's job. Changes for UL and LR were much smaller but they got closer to the pre-jump position, too. Don't pay much attention to the 1000 counts difference for  LL now VS pre-jump because it was reset. 

TITLE: 06/08 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
OUTGOING OPERATOR: None
CURRENT ENVIRONMENT:
    SEI_ENV state: MAINTENANCE
    Wind: 3mph Gusts, 1mph 3min avg
    Primary useism: 0.04 μm/s
    Secondary useism: 0.08 μm/s 
QUICK SUMMARY:

Lots of items today:  Continue finishing up ISS PD Array aligningment (then ground loop checks?), HAM3 SPI cabling/flange work + SPI main install, FARO for BBSS around HAM3, ITMy First Contact in-situ, HAM7 in-chamber.

Big M7.8 EQ ~15hrs ago (nothing tripped...although we have lots of SEI +SUS down for in-chamber work).

CEBEX crew continues laying brick (seeing about wall of 5-7 brick high this morning).

Friday June 5th we completed the assembly for the CRS that is going in HAM3. 

First thing we checked the alignment of the HoQIs, Fringe visibility: SN005 86% SN007 85%

We swapped out the photodiodes and cables in SN007 due to damage in one of the cables which meant the wire was exposed risking grounding issues should this touch any of the metal parts. The fringe visibility after this was at 72%. 

The HoQIs were completed with the baffles and top cover. SN007 cover is incorrect and the correct parts were not out of C&B so the wrong cover is on it at the moment this will be switched when we have the clean part. 

They were fixed to the CRS and aligned to it. SN007 is on the right and SN005 is on the left. Fringe visibility with the CRS fixed was as follows
SN007 sin 82% cos 80% mcos 82% SN 005 sin 83% cos 75% mcos 83%
The CRS was released and the fringe visibility for both left and right was checked, they were >80%, not all PDs were recorded but eg SN007 mcos was 82% 

(Gerardo M., Brandon P. (RMC Tech), Jordan V. (buddy))

Today the second oil pump was replaced on the Kobelco unit, no issues to report.  For previous work see aLOG 90318.

The purge air was isolated at the dryer towers and at the point of delivery before starting work.  Brandon shut off the compressor and stopped the dryer system, then removed and replaced the oil pump.  Kobelco compressor was re-started, oil measured, compressor was turned off to add oil up to nominal value, then the compressor was started and load tested.  No issues noted.  Brandon handed over the system.  I started the dryer towers back up, no issues noted.  Dew point from the local reading at the towers remained below -51 ^oC since the dryer system remained with both towers "loaded", and since there was no demand both remained pressurized.  After an hour with both the compressor and the dryer towers running at nominal, I opened the purge air to the LVEA lines.  After 45 minutes I took a couple of measurements.

Measurement results:

1. Point of use, near the purge port near HAM4 yielded a dew point of -43.2 ^oC
2. Same as before, near the dryer towers in the mechanical room, the dew point was taken before the big pressure regulator, port for the TMDS air supply, both towers yielded -44.4 ^oC.

Purge air is purging into the opened volumes.  Once again, please don't waste the purge air, if you can please keep those C3 door covers closed.  Thank you!

Leaving site now.

Short story:

RM2 was nicely relieved by rotating IM1 in YAW, ASC REFL sensors were centered, RM2 only used 40% of DAC range, people==happy (ASC-REFL-centered-20260605.png).

ISS QPD was nicely centered, it was easy, people==happy (iss_CENTERED.png).

Then suddenly we found that the IFO REFL beam is clipped at the bottom of the IFO REFL baffle, ISS array was totally out of whack, forward-going beam from IM2 was not centered on the retroreflection check iris between IFI input baffle and IFI HWP baffle, people!=happy.

Turns out that something bad happened to IM1 about 10 minutes after ISS was centered (IM1_bad.png). Without any change in the drive, H1:SUS-IM1_M1_OSEMINF_LL jumped by negative 172 counts causing apparent positive 1570urad jump in DAMP_P and DAMP_Y.  UR changed by 12 counts, which is like O(100urad) type change. 

This doesn't necessarily mean that IM1 moved that much, maybe one OSEM was bumped while we're trying to put the cover on the ISS, but the thing is that this must have caused physical rotation somehow because we see the beam moved downstream of IM1.

We tried to diagnose the IM1 but found no obvious touching, transfer functions didn't look wrong, EQ stops have gaps, magnets look as if they're OK.

You don't have to read further, below is our memo to remember what was done.

Details you don't want to remember:

We've made another YAW move (of positive 300urad) for IM1, i.e. [P,Y]=[517, -687] -> [517, -387] to relieve RM2 further.

Based on calculation, also moved IM2 and IM3 to roughly align things. IM2 [P,Y]=[0, -588.7] -> [0, -19] IM3 [P,Y]=[35.3, -415] -> [35.3, -86].

Checked the IFI output baffle and noticed that it seems to have an offset in -X direction relative to DKDP baffle. The beam was well centered on DKDP baffle, but was too much in +X direction on the IFI output baffle.

Moving IM2 further, [P,Y]=[35.3,  381] to split the difference.  Distance between the forward-going beam and the parking beamdump pickoff was ok.

This resulted in large IM3 Yaw step (IM3 [P, Y] = [35, 654]) to bring the beam close to the nominal position in front of PRM.  Horizontally, the beam was off by 0.5+-1mm in negative Y direction. Nominal beam height at the measurement point for PRM 159.05mm. Measured 157.1+-1mm.

IM4 Yaw moved by positive 350 ([IM4 [P,Y]=[761, -205]) to set the beam position in front of PR2. Horizontally, the beam was off by 0.5+-2mm in positive Y direction. Nominal beam height at the measurement point for PR2 168.56mm, measured 169.8+-2mm.

Centered the retro-reflection check iris to the forward-going beam between IFI input and IFI HWP baffle. Aligned PRM to center back-propagation on that iris. 

PRM [P, Y] = [-1185, -270].

Centered refl asc sensors. This worked really well, RM2 DAC was only using 40% of its range after centering ASC REFL sensors. Even though this was one attempt, I'm comfortable enough to say that we'll be fine.

Moved on to center ISS array. We removed the ISS array cover from the assembly to use the input aperture tool to make things easier. Large hole aperture as well as medium was used, didn't bother to use the small aperture. We used two pico mirrors (had to use hand because no driver is connected until the IOT2L is back). Iteration between two mirrors was easy and the centering was done by 22:37 UTC.

RM1 P, Y = -196, 209 (13% of DAC range)

RM2 P, Y = 609, -602 (40% of DAC range)

Happily we put the ISS array cover back on. Unknown to us, something happened to IM1 at around 22:46 UTC.  
 

Remaining task:

solve IM1 mystery?

shoot the pic of pico mirrors to see how much range we have.

center IM4_TRANS

take aperture photo for IFI inpjt and IM4 baffle, recenter IM4 baffle if necessary.

ground check.

Robert, Ibrahim, Anamaria

We finished alignment of the CP cage baffle on ITMX, which was the last item to do regarding cage baffles. The panels are locked so they can now be removed and replaced while retaining the alignment. 

Both ITMs have the (new) face shield on. ITMY suspension is unlocked and ITMX is locked. 

Begum, Ryosuke, Camilla, Madi

Summary: Were able to retroflect the beam off FC1 (when placed at O4 sliders) with ZM2 and ZM3 but the beam height is incorrect, as expected, VOPO optics will need to be moved to fix this. 

(Jordan V., Gerardo M.)

We have noticed that the dew point at the dryer towers has been increasing since opening to HAM7 and or related to power glitch last Saturday, we are still looking into it.

We have had a constant dew point at the dryer towers of -72 ^oC, and now we are at -57 ^oC, because of those numbers we ran a short test, once work was finished for the day in-chamber, we stopped the purge air to the LVEA to see what the effect was on the drying tower's dew point, it changed but very slow, we started at -57 ^oC and after 20 minutes we ended up at -59 ^oC, and we noted that the right tower may be in trouble since the dew point did not improved while this tower "works", the dew point instead went up by the one degree, erasing the improvement of the left tower.  We will look more into it.

To complete the test we took a dew point measurement at the point of use in the LVEA, and we got a -40.7^oC, getting close to a bad dew point, and remember this is while no in-chamber work is going on, so please mind those C3 soft covers on chamber doors, thank you.