TITLE: 05/15 Day Shift: 1430-2330 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: Alignment continued in HAM2 today after the Kobelco unit was worked on this morning. Ibrahim has been tidying up around the test stand area and wrapping up parts from the BSFM. Robert continued grounding studies at End X, and Jeff worked in the optics lab on SPI. His work requires leaving the laser running over the weekend in the optics lab; curtain is closed and proper signage is up.
LOG:
| Start Time | System | Name | Location | Lazer_Haz | Task | Time End |
|---|---|---|---|---|---|---|
| 19:43 | SAF | LASER HAZARD | LVEA | YES | LVEA IS LASER HAZARD | Ongoing |
| 14:59 | VAC | Jordan | LVEA | - | Check covers/RGA, shut down Kobelco | 15:11 |
| 15:32 | FAC | Kim | LVEA | - | Technical cleaning | 17:02 |
| 15:41 | SPI | Jeff | Opt Lab | Local | SPI prep work | 19:33 |
| 16:25 | VAC | Jordan | LVEA | - | Checking RGA | 16:30 |
| 16:39 | FAC | Randy | LVEA | - | Plugging in equipment | 17:31 |
| 16:40 | SUS | Ibrahim | LVEA | - | BSFM housekeeping | 19:21 |
| 17:20 | FAC | Kim | LVEA | - | Technical cleaning | 18:00 |
| 17:41 | ISC | Keita | LVEA | Y | HAM2 beam alignment | 17:55 |
| 17:55 | PEM | Robert | EX | N | Grounding studies (in/out all day) | Ongoing |
| 17:58 | VAC | Jordan | LVEA | - | Ramping up RGA temp | 18:04 |
| 19:47 | ISC | Keita | LVEA | Y | HAM2 beam alignment | 21:42 |
| 20:40 | VAC | Jordan | LVEA | - | Checking RGA | 20:45 |
| 21:32 | SPI | Jeff | Opt Lab | Local | SPI prep work | 22:57 |
| 21:49 | SUS | Ibrahim | LVEA | - | BSFM wrap, bag, tag | Ongoing |
| 22:38 | EPO | Oli +2 | LVEA | - | Tour | Ongoing |
| 23:05 | VAC | Jordan | LVEA | - | End-of-day RGA check | 23:10 |
J. Kissel
Quick summary of status and things done before the weekend:
2026-05-14
- Secured new D2400143-v6 breadboard to 1"Dx6"L posts
- w/ J. Freed Helicoiled most holes
2026-05-15
- Finished helicoiling and confirmed all holes have helicoils.
- Brought out IXM100 mounts that are to replace CVM100 mounts, confirmed left vs. right-handed assignment
- Fit-checked (success!), then installed new version of 45 deg periscope adapters to M_M4 and M_M5 mounts.
- Aligned periscope adapters as best possible by eye
- Migrated over and re-cabled up all photodiodes per wiring diagram and cable routing defined in LHO:90228.
- Migrated R_F1 and M_F1 fiber collimators, confirming and adjusting alignment of slow-axis w/ vertical flat.
- Re-connected optical fiber input to each collimator.
- Re-introduced beam on to breadboard confirming that NPRO and Laser Prep Chassis still work as good as we left it.
- Measured raw power from R_F1 and M_F1 fiber collimator output using S121C power meter.
- Aligned R_F1 and M_F1 fiber collimator output using
- D2500080 alignment iris target assemblies
- D2400143-v6 holes 89 + 101 for R_F1 and 101 + 80 for M_F1 and
- S121C behind the "far" iris, maximizing power throughput.
- Migrated R_P1 and M_P1 thin-film polarizers.
- Measured P-pol (TRANS) and S-pol (REFL).
- Migrated D_R_P1 and D_M_P1 beam dumps.
Optical power going into the mock PSL input fiber is ~195 [mW] as we left it, and internal laser prep chassis reads 7.8 [V] implying that input power to the chassis is the same 173 [mW] we set it to, to match the real PSL input (see LHO:89693).
RF power on power monitors from prep chassis are as expected, in the 750 +/- 10 [mV] range.
Measuring power with our trusty S121C with ThorLabs PM100-D readout (confirmed to be measuring at 1064 [nm] wavelength): Josh and I hard at work doing helicoil science. Photo credit: Ryan Short.
TITLE: 05/15 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: 6mph Gusts, 3mph 3min avg
Primary useism: 0.06 μm/s
Secondary useism: 0.13 μm/s
QUICK SUMMARY: Work in HAM2 continues today as part of the ISS swap, but not until the Kobelco unit has had some maintenance done this morning. No in-chamber work allowed until that's finished. 31 disconnected channels on the EDC since the corner HEPI pump controller appears to still be down.
In other news, a M6.7 EQ out of Japan is rolling through, and it's a beautiful morning on-site.
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,
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:
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:
On top of pictures below, 2 videos:
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:
At this point I and Rahul checked the beam positions in HAM2. Some things to note:
We proceeded to swap the ISS array unit.
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 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.
1st: Rahul is disconnecting the QPD cable.
2nd, 3rd (photo by Betsy): Rahul in chamber (me outside).
4th: Old unit was extracted. This is S1202971.
5th: New unit (S1202965) to the left, old one to the right.
6th: Rahul after successfully connecting up the new unit in chamber.
7th (photo by Betsy): Elenna (front) is checking the QPD centering, Rahul (a shadow in the back in this photo) is manually moving the pico mirror from -Y door, and I'm somewhere inbetween just observing the two doing a good job.
epo tagging for photos!
Attaching two pictures in reference to Keita's comment above - "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)"
We concluded that the height of the baffle and the array unit are both correct, the beam is really too high on the 1" lens and we're shooting down from there to the QPD. (This should have been the case for a long time with the old unit. Right after the new unit was installed the beam was on QPD and the beam stayed on the QPD, the diameter of the QPD is 3mm, i.e. we haven't made any huge change on the height of the beam at the left baffle hole.)
With this information, what we'll do next is to gradually bring down the height of the beam on the left baffle hole using the first pico mirror, and use the second pico mirror to bring the beam back on the QPD, until the beam line into the array becomes level-ish with the ISI surface. It doesn't have to be perfect but we don't want to be this much tilted.
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:
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:
(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.
(Jordan, Travis, Gerardo)
CP1 soft regeneration update, CP1 pumpdown continues, system is currently pumped down by the SS500 cart, one turbo pump and one scroll pump. Yesterday we visited the sensing line and we injected high purity nitrogen gas, we removed the lower sensing line near the Rosemount sensor to be able to inject the nitrogen gas, no issue introducing the gas, lower sensing line appears clear.
To be done, leak check CP1.
Attached is a plot of the pressure internal to CP1, the plot is for the total ongoing soft regeneration.
(Jordan, Gerardo)
We leak checked CP1, specifically the bi-braze joints, we introduced He to both sensing lines (we disconnected the lines before the 3 way valve -X marks the spot - , this is less disruption to the shape of the metal tubing lines), we started with the bottom or low sensing line, we introduced 1 psi of flow into the line for about 35 seconds, no signal was detected by the leak detector attached to the exhaust of the turbo pump. We did the same test with the high sensing line, no signal was detected. Since we had the setup on hand we also decided to spray all the bellows, given that now they are free of ice, sprayed helium for about 35+ seconds, no signal was detected by the leak detector at any of the points sprayed.
During all the tests performed the He background at the leak detector was 1.0X10-10 Torr*L/Sec.