Good news is that we're done with the alignment of the ISS path. Pictures and details are to follow.

Then I reinstalled the last IFO REFL baffle right in front of the HAM2-HAM1 septum window. (The baffle was removed after marking the exact position using three temporary dog clamps on the ISI on day 1 because it was in the way, I was supposed to record that in alog 90158 but forgot. I'm absolutely sure that the position of the baffle was restored within 0.1mm of the original position.)

Bad news is the IFO REFL was clipped on that baffle. 00 mode flash isn't clipped that much but horizontal modes certainly are. That was not THAT surprising because the IMC alignment was/is not great (see my comment 90224). This looks to me that the uncontrolled degree of freedom of the IMC is wrong regardless of the reason why a huge alignment change had to be made to center the MC2 TRANS QPD.

Good news is the ISS path alignment is not impacted by that, at least greatly, because we made sure that the beam hit the right location of IM4 TRANS as well as ISS array QPD before we did anything in the ISS path. Note that the baffle clipping the beam is not in the ISS path.

In other words,

• the beam position on MC3 might have been poor but we used IM3 and IM2 to steer the beam INTO the ISS path such that the alignment there is reasonably close to in-vac alignment,
• when the beam coming out of MC3 is brought back to the good position/angle, we can bring the beam back onto IM4 trans using IM3 and IM2,
• if the beam is not found on the ISS QPD at that point, we can scan IM3 (and IM2 if necessary) further to find the beam,
• and use the first pico for the ISS array path to keep the beam on the array QPD while slowly bringing IM3 (and IM2 if that's touched) back to the good angle.

However, since we don't want to revisit HAM2 once we close it, I'd like to understand what's going on for the IMC/IFO alignment. 

To close out the week, we got stops and shroud mounts installed on the 2 CRS today. This is as far as we can go until we can get flexures or start assembling HOQIs, so probably not much more to report until later next week. We've covered the CRS in foil to protect them, and packed up the left over hardware for these 2 sensors. 

TITLE: 05/14 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:

Cement truck convoy day for CEBEX today.  Bigger BeamSplitter "captured" in the suspension assy & FARO-ed in the afternoon.  A couple big middle school tours.  ISS Array alignment continued.
LOG:

• 1438 Kim finishing up with garb supply checks.
• 1524 technical cleaning in lvea (kim)
• 1543-1709 Charge Measurements (ryanC)
• 1547-1554 checking on pumps and overall VAC status (jordan)
• 1553 Rebar inspector arrived for CEBEX
• ~1615 LVEA transitioned to SAFE for....
• ~1615-1813 BBSS work (ibrahim,betsy,oli)
• 1640:  susr2 rack work near ham3 (josh)
• 1648:  Cement Truck convoy begins to MY!!
• ~1650 CP1 checks (travis)
• 1713-1723 Finley Middle School Tour (amber)
• 1715-2035 cleaning tests in-chamber....turned ON illuminator in BSC3 (bsc1 & bsc2 is already ON) (robert.tj)
• 1717-1755 Walkabout in lvea (richard)
• 1727-1821 technical cleaning in lvea (kim)
• 1758-1814 Finley Middle School 8th grader tour (maggie)
• 1815-1833 LVEA Transition back to HAZARD (tony)
• 1824- 2137 Corner rga (jordan)
• 1920-1930 checking FARO parts (stephenA)
• 1942-2324 team-ISS Array starting chamber work (keita)
  • 2002-2248 rahul joining
  • 2015 elenna joining
• 1943 -2120 team-BBSS back at it (ibrahim, betsy, randy)
• 1955-2012 Warming up FARO (jason)
• 2013-2225 CRS work in the CRS Lab (jim.shoshanna.michaelR)
• 2015-2158 SPI alignment + possible laser hazard (jeff.josh)
  • 2158 jeff out
  • 2224 josh out
• 2022 Connection alarm for HEPI_PUMPS, not a beckhoff issue, so will need jim to restore (notified Jonathan.patrick/CDS + Jim)
• 2038-2111 MER to check on HEPI cabling (fil)
• 2041-2055 connecting with jordan + betsy (travis)
• 2108-2258 sqzt7 beam profiling, turning sqz laser ON for this work and OFF when done (sheila.ryanS.tony)
• 2109-2328 team FARO getting set up at Test Stand (jason.ryanC)
• 2140 turned BSC123+HAM3 illuminators OFF (corey)
• 2243-2301 Checking out a pelican case (b&k) near HAM6 (tj.jim)
• 2246-2252 corner rga check (jordan)
• 2304 Checking on corner station HEPI Pump Station (jim)
• 2312 More BSC2 cleaning & tests.  Turned BSC123 + H3 illuminators back on (robert w/ Oli-buddy)

Ibrahim, Betsy, Oli

Today, we installed BBS01 into the BBSS successfully. 

BBS01 was on a table. BBSS was on the aluma lift. We picked BBS01 using the ERGO arm and slowly came into the optic. In this process, we:

• Removed the EQ stops and replaced them with the glass tips
• Ensured that the gold wire was held correctly about the lower structure barrell
• Made contact between the gold wire and the grooves of the prisms
• Backed the glass tip EQ stops in to contact, securing and locking the whole suspension (M1 and M2 were already locked)
• Installed the BBSS face shields
• Practiced a lift of how it would go up into the test stand
• Placed teflon pads between the lift arms and the BBSS 45 degree lifting bars - LLO did the same (alog 80802) - this helps with fine structure adjustment when below the ISI
• Covered the BBSS on the lift in prep for test stand install (IAS needs time with the ISI to get exact positions in XY for where BBSS will sit).

On top of pictures below, 2 videos:

• Pushing BBS01 In
• ERGO Arm Sighting and Adjustment

I spun the iNCal (currently installed version) at a low speeds to see if low speed operation shows the same vibrations that high speed operation does (see 67207). Even rotating at 1 Hz shows a large increase in signal in the accelerometer (H1:PEM-EX_ACC_BSC9_ETMX_Z) around 200 Hz. 7 Hz shows an order of magnitude increase between 100-300 Hz. The 0 Hz spectrum is with the iNCal powered but a set speed of 0 Hz. 

The lesson is that the iNCal will inject broad band noise in the strain readout even at very low speed operation.

I ran the oplev charge measurements this morning for both of the ETMs, previously checked in alog89906.

ETMY's charge remains largely unchanged, the values across the quadrants remain below 100 on all quadrants/DOF and I don't see any appreciable trends. As a reminder we switched off the HV digitally for EY.

ETMX's charge is decreasing across all quadrants/DOF after the sign flip we inposed back in April. Over the past 4 weeks the average decrease for P was ~ -14 [V], and ~ -18.25 [V] for Y. UL saw the greatest decrease, a drop of over 30 [V] for both P & Y, UR saw the smallest decrease, around ~ 5 [V] for both P & Y. The charge is now at or below 50 [V] on all quadrants/DOF except UR_P and LR_P.

TITLE: 05/14 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: 5mph Gusts, 3mph 3min avg
    Primary useism: 0.01 μm/s
    Secondary useism: 0.23 μm/s 
QUICK SUMMARY:

New ISS Array alignment will continue as well as work with the new Bigger BeamSplitter. 

No alarms overnight. Clearer & calmer weather this morning.

With the better weather, perhaps the DGR subcontractors will start pouring concrete for the CEBEX walls today (this will require the main gate to be left open for the cement trucks to roll through.  (WP# 13250)

Following yesterday's alog 90219:

• IM2 and IM3 were reverted back to Monday evening position just using the slider values.
• Using flashes, confirmed that the IM4 trans as well as ISS QPD were roughly at the same position as the Monday evening position.
• Elenna confirmed that ISS OUTER SUM flash peak minus dark offset was 0.031 with 200mW input. (INNER SUM was much smaller.) Back in March it was 0.062 with 2 W input. So somehow the alignment into ISS array used to be REALLY poor.

At this point I and Rahul checked the beam positions in HAM2. Some things to note:

• The beam was uncomfortably close to the holes in the last baffle before the ISS array. It might have been clipped back in March. See ISS_two_hole_baffle.png showing the flash on the right hole. That hole is the "exit" hole for the reflection of the last pico mirror. Left hole is for the incoming beam from the 1" lens (which is right behind the baffle in the picture) but we couldn't take a good photo of the flash in the left hole at the time.
• Once the beam clears the last baffle, the beam is not clipped by the array cover nor the input hole of the array elevator plate.
• IM4 trans beam goes to the first pico mirror cleanly without getting clipped, and it's not clipped at all on the 2" lens.
• IMC trans beam from MC3 hit the IM1 cleanly, clears the baffle after that (IMC_REFL_peri.jpg), and appeared to go to IM2 without getting clipped. Couldn't check IM2->IFI->IM3 but no reason to get suspicious either. 
• IM1 transmission was clearly visible using a card and the IR viewer, it was not clipped by the suspension cage with considerable marging and was hitting the steering mirror behind IM1. 
• IMC REFL comes out of the last (second) IMC REFL periscope cleanly, the beam is well centered on the baffle hole. See IMC_trans_after_IM1.mp4.

We proceeded to swap the ISS array unit.

• Rahul went inside HAM2 and disconnected the QPD and array PDs after powering down the transimpedance amplifiers. Note that ISS QPD TIA shares the chassis with the IM4 trans, so IM4 trans went dark for some time too. 
• The old array assy was separated from the ISS array spacer. The latter remained in the chamber, only the top assy was swapped, as was explained in alog 90158.
• The new array assy SN1202965 (S1202965) was put on top of the array spacer. We took time to double check that the bias voltage for QPD comes to the expected pin on the QPD connector before making connection because the connector could be rotated by 90, 180, or 270 degrees and we can ruin some quadrants. Array PD cables were straightforward, it went as planned in alog 90158.
• TIAs were turned on.

At this point we saw flashes on QPDs as well as array PDs right away. INNER as well as OUTER SUM flashes were both about 0.06 (in the old unit it was 0.03 for OUTER but INNER was much smaller).

We started trying to center the QPD using the first pico mirror. Since pico driver is temporary unavailable (IOT2L is moved away) Rahul turned the pico manually while Elena looked at the laptop screen to monitor flashes in the individual segments. We managed an OK job (arrayqpd_centered.jpg) and checked the beam spots again.

• The beam was very high on the left hole of the two-hole baffle (Rahul has a good pic), high on the right hole (right_hole_after_new_array_QPD_centered.mp4), and OK on the input hold of the array (array_input_after_new_array_QPD_centered.mp4).

The baffle height might not be the same as the lens height and/or the ISS array input hole height, but otherwise it seems that we're shooting down the beam from the 1" lens to the ISS array. We'll check if the lens, baffle and the array are all at the same height or not, and decide how to proceed.

Shoshana, Michael, Jim

Today we went into the PSL and started putting together the 2 complete CRS assemblies we have cleaned and ready to go. This went pretty smoothly and we now have to mostly done CRS, sans HOQI readout. We don't have flexures we can use, so we can't suspend or do any mechanical tuning, but proof masses are installed in the frames, mass adjustment hardware and picos are mounted. Tomorrow, we will probably look at what prep we can do on the other 2 CRS, but fasteners are still working through c&b for those, so I don't know there is much to do until those come out.

Ibrahim, Betsy, Randy

Today, we:

• Took the BBSS out of the can after securing the BSFM.
• Prepped the BBSS
  • blew the suspension with nitrogen top gun from top down
  • took the lifting plates out and set it down on its assembly tooling
  • attached the 45 degree lifting arms
• Prepped the ERGO arm
  • 2 adjustment O-rings had to be re-installed
  • BBS plate was used to lift practice glass
  • Dry run of where it would go with the optic was done
• Prepped the Aluma-Lift
  • cleaned the lift arms
  • positioned and dry-ran the path it would take during install 

Particle counts were checked periodically and were under 75 consistently during acitvity

See pictures.

TITLE: 05/13 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 and BBSS work continues.  Had a couple of big school field trip visits.

Odd weather day with fairly high winds and rain for most of the day.
LOG:

• 1534-1717 technical cleaning (optics lab and then LVEA + set-up at the old H2 PSL enclosure for upcoming work to be done inside it) [kim]
• 1545-1805 SQZT7 taking panels off (sheila)
  • 1556-1657 tony joining
• 1554-1746 BBSS work working on connecting the Bigger Beamspliter to the suspension frame in the coming days (ibrahim)
  • 1601- betsy joining
  • 1643 oli joining
  • 1700 randy joining
• 1611- 1613 Opening PSL Light pipe for ISS pd array & returning to control room to look at alignment (keita)
• 1627-1634 HAM6 ramp down rga bakeout & then move to CP1 to begin leak checking (jordan)
• 1708- ~2000 CRS (Cyllindrical Rotation Sensor) work at h2psl (jim,michaelR,shoshana)
• 1713-1935 ISS PD Array (keita,rahul)
• 1732-1815 EX ground studies continue (robert)
• 1736-1850 technical cleaning @EX (kim)
• 1751 SUSR2 rackwork for SPI (josh)
• 1800-1918 BBSS team returns for test stand to continue move to install the Bbs (betsy.randy.ibrahim)
• ~1730-1838 TCS plumbing work (tj,madi)
• 1830-1845 Outlook Elementary School tour (Amber)
• 1915-1930 Outlook Elementary School tour (Cassidy)
• 2018- 2149 TCS plumbing work cont.; will leave the chiller ON overnight. (tj,madi)
• 2039-2252 BBSS team returns to Test Stand (ibrahim, betsy, randy)
  • 2216 randy out
• 2042 HAM6 RGA (jordan)
• 2046-2230 SPI build + possible laser hazard in the optics lab (Jeff)
• 2049 CRS work at h2psl (jim,michaelR,shoshana)
• 2049-2155 electronics work for CRS near h2psl (richard,fil)
• 2055-2116 Escorted rebar inspector to CEBEX site & made lunch (corey)
• 2100 ISS PD Array alignment cont (keita.rahul)
  • 2229 Elenna joining for picomotor help
  • 2329 Rahul out
• 2206 restarting bake of RGA at HAM6 and another quick check at 2330 (jordan)
• 2238-2255 Closing TCSy table (was letting it dry out) [tj]

Ibrahim, Betsy, Oli

BBS01 AOSEM flag standoffs were removed, concluding gluing.

BBS01 was flipped to the HR Side via the inspection fixture.

Betsy and I then first contacted the HR Side (S1) and peeled an hour or so later.

We did not see any features or defects as we did with S2.

Camilla C, Madi S., TJ S

Just as we did with the TCSX table a few weeks ago (alog90078), we swapped all of the flex lines on the table. Most of this was done last week, but today Madi and I fisnished the last two lines today. We then used the same vacuum trick to suck water into the table lines to "test" the lines over lunch, and then plugged the table back into the full system and slowly turned on the chiller. We had one leak at the laser driver, but cutting and reseating the 1/8"OD tube seemed to fix it. 

While trying to removed the old 3/4"OD return tube from the tee, I managed to bump the iris next to the bottom periscope mirror. We'll have to recheck this when we have beam again and can some HWS tests.

The chiller is running, I'll check on things in the morning.

H1 ISI CPS Sensor Noise Spectra Check - Weekly FAMIS 39336

For some context, most of the Corner station is vented and the BS cartridge is not in the chamber which explains what is shown on the BS plots here..

Restored the alignment sliders for IM2 and IM3 back to Monday values ([IM2P, Y] =[765, -187.7], [IM3P, Y]=[-560.7, 320]).

Measured the flashes. Chose the flash that gave the MC2 trans sum maximum power, which in general agreed with IM4 trans sum max but didn't with ISS QPD nor array PD inner sum nor outer sum. 

Anyway, 

• MC2 trans: SUM=21; seg1=0.0027; seg2=0.0029; seg3=0.0024; seg4=0.0022
  • i.e. PIT=0.098, YAW=-0.039
• IM4 trans: SUM=0.0276; seg1=0.00876; seg2= 0.00760; seg3=0.00456; seg4=0.00526
  • i.e. PIT=0.25, YAW=0.07
• ISS QPD: SUM 362; seg1=67; seg2=13; seg3=13; seg4=271
  • i.e. PIT= -0.56, YAW=0.86
• ISS Inner: SUM 0.023
• ISS Outer: SUM 0.104

PIT and YAW numbers were after normalization divided by (seg1+2+3+4), not by SUM, so there's a small difference but that doesn't matter at this point.

IM4 TRANS and ISS QPD PIT and YAW are broadly in agreement with Jenne's alog 90206 i.e.

• IM4 Trans Pit 0.2 Yaw 0.05 (Monday)
• ISS QPD Pit -0.53 YAW 0.85 (Monday)

I haven't compared the ISS Outer SUM with March 2026 when IMC was locked with 2W. Somebody check please. We'll go into chamber and start checking the beam path.

(Jordan V., Dave B., Gerardo M.)

The internal pressure to CP1 turned around overnight signaling that the process of emptying the trap is complete, now we'll continue to monitor and pump on the cryotrap volume.until good pressure is achieved.

A side note, I manually turned off the CC for PT114B last night at 9:44 pm (local time) as the pressure was rising a bit high, then turned it back on this morning at 5:33 am local time.

Attached is a snapshot of one day trend data of pressure behavior regarding the soft regeneration for CP1.

Process started here.