Ops Day Shift Summary

TITLE: 01/10 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: More JAC installation and HAM7 beam alignment today. The LVEA is now Laser SAFE in preparation for craning on Monday morning.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
17:16	SAF	LASER HAZARD	LVEA	NO	LVEA IS LASER SAFE	Ongoing
16:12	FAC	Kim, Nellie	LVEA	-	Technical cleaning	17:38
18:12	JAC	Keita, Jennie, Masayuki	LVEA	Y	JAC installation	20:33
18:21	FAC	Kim, Nellie	LVEA	-	Technical cleaning	18:44
18:25	SQZ	Sheila, Kar Meng	LVEA	Y	HAM7 beam alignment	20:25
19:28	PSL	RyanS	PSL	Local	Getting tools	19:52
20:11	CDS	Daniel	CER	-	Rebooting Beckhoff chassis	20:16
20:57	CAL	Tony	PCal Lab	Local	Swapping spheres for measurement	21:46
21:39	JAC	Masayuki	LVEA/Opt Lab	Y	Parts pickup, JAC installation	01:53
22:01	JAC	Jennie, Sophie	LVEA	Y	JAC installation	02:05
22:06	SQZ	Sheila, Kar Meng	LVEA	Y	HAM7 beam alignment	00:17
22:13	JAC	Keita	LVEA	Y	JAC installation	02:13
23:21	CAL	Tony	PCal Lab	Local	Check measurement	23:26
01:39	PSL	Ryan Short	LVEA & PSL Enclosure	Yes	Transitioning the LVEA & closing up the PSL enclosure.	01:43

HAM7 progress, beam reaches HAM6 more alignment work ahead

Kar Meng, Sheila

Today we shifted the beam in SFI2 to be more centered on the second polarizer, to hopefully get rid of our scattered light shelf, and aligned the beam coming off the VIP to an iris in front of ZM4 and two irises on SQZT7, by moving B:M3 and B:M4.  After this we let the beam through the viewport into HAM5.  We see some light on AS_C, AS_A and AS_B, but it is not well aligned onto those diodes and we had trouble engaging the AS centering loops.  

Since we shifted the beam in SFI2 we have misaligned it onto the FC QPDs, we can see this beam is now clipped on the lens D:L1.  We were able to realign onto this my moving B:M3, but this misaligned the beam in the main path irises. 

 

h1lsc, h1ascimc model restarts. New slow controls INI, DAQ restart

Daniel, Ryan S, Dave:

h1lsc: We installed Daniel's latest model, a DAQ restart was required.

Slow controls: Daniel's latest INI files were added to the DAQ, an EDC restart was required.

h1ascimc: Daniel found some ADC discrepancies, I fixed them at the top level of the h1ascimc model. No DAQ restart was required.

Following the restarts of the h1lsc and h1ascimc models, the DAQ+EDC were restarted in the order: 1-leg, EDC, 0-leg. There were no problems with these restarts.

HEPI Pump Trends - Monthly

FAMIS 38864

Looks like at the power outage on December 4th there was either a significant drop in pressure at pump station 1 or a setting was lost that changed the readout. A jump is also seen at that time in the output voltage. Otherwise, trends look steady.

PSL Status Report - Weekly

FAMIS 27706

Laser Status:
    NPRO output power is 1.83W
    AMP1 output power is 70.47W
    AMP2 output power is 140.3W
    NPRO watchdog is GREEN
    AMP1 watchdog is GREEN
    AMP2 watchdog is GREEN
    PDWD watchdog is GREEN

PMC:
    It has been locked 0 days, 23 hr 31 minutes
    Reflected power = 26.88W
    Transmitted power = 104.5W
    PowerSum = 131.4W

FSS:
    It has been locked for 0 days 23 hr and 30 min
    TPD[V] = 0.4004V

ISS:
    The diffracted power is around 4.0%
    Last saturation event was 0 days 0 hours and 0 minutes ago

Possible Issues:
    PMC reflected power is high

Vibration Sensors To Gauge Health Of HVAC Fans Famis

Closes : Famis 27647 Using Vibration Sensors To Gauge Health Of HVAC Fans. 

Vibrometers look fine and don't seem to be abnormally performing yet. 
 

Fri CP1 Fill

Fri Jan 09 10:07:59 2026 INFO: Fill completed in 7min 55secs

 

Ops Day Shift Start

TITLE: 01/09 Day Shift: 1530-0030 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, 2mph 3min avg
    Primary useism: 0.03 μm/s
    Secondary useism: 0.42 μm/s 
QUICK SUMMARY: JAC install and SQZ alignment work slated for today, although probably a quieter day ahead.

Thursday Ops shift summary.

TITLE: 01/09 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY:
DAQ restart at 23:46 UTC

Mostly JAC & SQZer work was done today.
Fil did put hook up the HV for JAC use.
Light pipe is should and has been double checked to actually be shut.

LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
17:16	SAF	LASER HAZARD	LVEA	YES	LVEA IS LASER HAZARD	01:35
15:59	FAC	Kim & Nellie	LVEA	yes	Technical Cleaning	18:00
16:06	Inventory	Christina	MX	N	Dropping off parts.	18:06
18:31		Mikes + Crew	LVEA	Y	Tour of the LVEA for an interview canidate	19:46
19:07	SQZ	Sheila, Kar Meng	LVEA	Y	HAM7 work cont	20:14
19:11	ISC	Rahul, Masayuki, Jason	LVEA	Y	HAM1 cabling, disconnect JM1, Rahul out b20:17	20:42
19:22	ISC	Jennie, Marc	PREP lab/ LVEA	N / Y	Grab cables and bring them to the LVEA HAM1	20:29
19:33	JAC	Betsy	HAM1	yes	checking the JAC progress	19:57
19:36	JAC	Elenna	HAM1	Y	Helping the JAC team	20:14
19:45	EE	Marc	LVEA	Y	Help ID cables at HAM1	20:29
20:53	EE	Fil	HAM1	y	Turning on High Voltage for JAC crew	21:26
21:36	JAC	Masayuki, Jennei W.	HAM1	yes	doing JAC work & research.	00:36
21:40	JAC	Elenna & Derek	LVEA	y	Rubbernecking near the HAM1 & HAM7	22:27
21:53	JAC	Jason	LVEA	yes	Working on JAC	00:48
22:45	PEM	Jim	EY	N	Getting Wind Fence numbers.	22:59
23:10	JAC	Richard	LVEA	Y	Checking on the JAC status	23:27
23:20	PCAL & JAC	Rick	PCAL Lab & LVEA	YES	Swapping spheres & then Rubbernecking past HAM1	23:44

 

new h1lsc model installed, DAQ restart was needed

Daniel, Erik, Jonathan, Dave:

we installed Daniel's modifed h1lsc model. This required a DAQ restart.

DAQ 1leg was restarted at 15:47, followed by the 0leg at 15:52.

 

PSL Cooling Water pH Test - Monthly

FAMIS 27733

pH of PSL chiller water was measured to be between 10.0 and 10.5 according to the color of the test strip.

Thu CP1 Fill

Thu Jan 08 10:02:56 2026 INFO: Fill completed in 2min 54secs

 

JAC in HAM1

[Jason, Rahul, Jennie, Betsy, Masayuki]

Summary

JM1 was swapped from a tip-tilt suspension to a fixed Siskiyou mount to improve beam stability for alignment, profiling, and JAC control. Mode matching to the JAC was measured using a beam profiler, yielding <1.5% mismatch in both axes, well within the current requirement. The JAC pedestal and body were installed in HAM1, and initial beam injection showed clear HoM resonances at the transmission port. One discrepancy in body mode damper mounting holes was identified and will be tracked via FRS.

Details

• After discussion, we decided to replace the JM1 tip-tilt suspension with a fixed Siskiyou mirror mount. This provides easier alignment, beam profiling, and more stable JAC control compared to using a suspended mirror. As reported in the previous alog, JM1 had already been aligned to the target irises with a good angle, so the position of the JM1 suspension was marked with dog clamps to allow easy recovery of the alignment after installation work. The Siskiyou mount was aligned using the same target irises.

• After switching the mirror mount, a beam profiler was set up in the reflected beam path from the fixed JM1 to measure mode matching to the JAC, as shown in the attached picture. The z-origin was defined at the position where the beam profiler cart reading was set at 16 cm along the rail. Due to cable length limitations, beam size measurements near the waist were not possible, but this was not considered a significant issue.

• The measurement results are shown in the attached plot. The target and measured beam parameters are:

  • w0_target = 548.00 µm, z0_target = −4.318e−01 m

  • w0_x = 572.01 µm, z0_x = −5.277649e−01 m

  • w0_y = 603.50 µm, z0_y = −3.736913e−01 m

• The resulting mode mismatch was 1.363% (x) and 1.455% (y). Our current target for mode mismatch is 10%, which is sufficient for achieving a reasonable JAC lock. Therefore, this result is excellent and no further adjustment is required at this stage. Fine tuning may be performed later after JAC lock, possibly after HAM1 pump-down.

• The JAC pedestal was installed and secured to the table, and the shim was placed on the pedestal.

• The JAC body was then brought into the chamber. The procedure was recorded on video. A handle (not Class-B cleaned) was temporarily attached to the JAC; it was wiped down, and aluminum foil was inserted between the handle and the JAC body. During installation, Jason and Rahul supported the body from the sides while I handled the lift into HAM1. The end caps protecting the mirrors remained installed throughout this process.

• During installation of the body mode dampers, we found that one of the screw holes specified in the drawings was missing. The location of the missing hole is shown in the attached picture. As a result, one body mode damper was shifted by one column of screw holes (a 2″ offset). We discussed this with Stephen and believe it should not cause an issue, although it will be monitored. An FRS ticket will be submitted to track this discrepancy.

• After removing the end caps, the beam was injected into the JAC for a quick alignment check. A higher-order mode (HoM) resonance was immediately observed at the transmission port, confirming successful initial alignment. The next steps are fine alignment of the input and reflected beams, followed by in-vacuum wiring.

 

Thursday Ops Shift Start

TITLE: 01/08 Day Shift: 1530-0030 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: 0.05 μm/s
    Secondary useism: 0.87 μm/s 
QUICK SUMMARY:

Trello summary for today: 
HAM! -mode matching check - Laser Hazard
HAM1 - JAC install & Anignment
HAM7 - More SQZ work- Laser Hazard

LVEA is currently in Laser Hazard status.
 

 

Current Backlog of SatAmp Swap Comparisons (MC1(M2, M3), MC2(M2, M3), MC3(M2, M3), PR3(M2, M3), SR3(M2, M3), ITMX(L2), ITMY(L2), ETMX(L2), ETMY(L2))

Here are the rest of the satamp swap comparisons for the rest of the suspension/stages that we've upgraded as part of ECR E2400330. These were all swapped a while ago but I'm just getting around to making these comparisons now.

Overall, we do see a bit of improvement for these stages, although the high noise floor of the AOSEMs limits the amount of improvement we are able to see.

Notes about the results:
- ITMY L2: the original modified satamp that was swapped in on 10/14 ended up having issues and needed to be replaced on 10/16 with another modified satamp (87685). Because of this, the 'after' time that I chose here is after the second (working) satamp was installed
- ETMY L2: the original modified satamp that was swapped in on 10/14 ended up having issues and needed to be replaced on 10/24 with another modified satamp (87722). Because of this, the 'after' time that I chose here is after the second (working) satamp was installed
- SR3 M2: The comparison listed here is basically useless because it seems like there might have been something wrong with the old unmodified satamp. See 88706 for more info

Swapped Oct 14, 2025 (87469):
ITMX L2
ITMY L2 - needed to be swapped again Oct 16 (87685)
ETMX L2
ETMY L2 - needed to be swapped again Oct 24 (87722)

Swapped Oct 21, 2025 (87620):
MC1 M2, M3
MC2 M2, M3
MC3 M2, M3
PR3 M2, M3
SR3 M2, M3

 

ITMX
L2
Results:
$sussvn/QUAD/H1/ITMX/SAGL2/Results/allDampRegressCompare_H1SUSITMX_L2_NoiseComparison_1443956643vs1444642495-1200.pdf
$sussvn/QUAD/H1/ITMY/SAGL2/Results/allDampRegressCompare_H1SUSITMX_L2_1443956643vs1444642495-1200.mat
Data:
$sussvn/QUAD/H1/ITMX/SAGL2/Data/dampRegress_H1SUSITMX_L2_1443956643_1200.mat
$sussvn/QUAD/H1/ITMX/SAGL2/Data/dampRegress_H1SUSITMX_L2_1444642495_1200.mat
r12824

ITMY
L2
* Since the satamp swapped in on 10/14 had issues and had to be swapped out on 10/16 for another modified satamp (87685), the 'after' time is with the working modified satamp
Results:
$sussvn/QUAD/H1/ITMY/SAGL2/Results/allDampRegressCompare_H1SUSITMY_L2_NoiseComparison_1443956288vs1445199479-1200.pdf
$sussvn/QUAD/H1/ITMY/SAGL2/Results/allDampRegressCompare_H1SUSITMY_L2_1443956288vs1445199479-1200.mat
Data:
$sussvn/QUAD/H1/ITMY/SAGL2/Data/dampRegress_H1SUSITMY_L2_1443956288_1200.mat
$sussvn/QUAD/H1/ITMY/SAGL2/Data/dampRegress_H1SUSITMY_L2_1445199479_1200.mat
r12825

ETMX
L2
Results:
$sussvn/QUAD/H1/ETMX/SAGL2/Results/allDampRegressCompare_H1SUSETMX_L2_NoiseComparison_1442915673vs1445261656-1200.pdf
$sussvn/QUAD/H1/ETMX/SAGL2/Results/allDampRegressCompare_H1SUSETMX_L2_1442915673vs1445261656-1200.mat
Data:
$sussvn/QUAD/H1/ETMX/SAGL2/Data/dampRegress_H1SUSETMX_L2_1442915673_1200.mat
$sussvn/QUAD/H1/ETMX/SAGL2/Data/dampRegress_H1SUSETMX_L2_1445261656_1200.mat
r12826

ETMY
L2
* Since the satamp swapped in on 10/14 had issues and had to be swapped out on 10/24 for another modified satamp (87722), the 'after' time is with the working modified satamp
Results:
$sussvn/QUAD/H1/ETMY/SAGL2/Results/allDampRegressCompare_H1SUSETMY_L2_NoiseComparison_1442915673vs1445434776-1200.pdf
$sussvn/QUAD/H1/ETMY/SAGL2/Results/allDampRegressCompare_H1SUSETMY_L2_1442915673vs1445434776-1200.mat
Data:
$sussvn/QUAD/H1/ETMY/SAGL2/Data/dampRegress_H1SUSETMY_L2_1442915673_1200.mat
$sussvn/QUAD/H1/ETMY/SAGL2/Data/dampRegress_H1SUSETMY_L2_1445434776_1200.mat
r12827

MC1 
M2
Results:
$sussvn/HSTS/H1/MC1/SAGM2/Results/allDampRegressCompare_H1SUSMC1_M2_NoiseComparison_1442005989vs1449002022-720.pdf
$sussvn/HSTS/H1/MC1/SAGM2/Results/allDampRegressCompare_H1SUSMC1_M2_1442005989vs1449002022-720.mat
Data:
$sussvn/HSTS/H1/MC1/SAGM2/Data/dampRegress_H1SUSMC1_M2_1442005989_720.mat
$sussvn/HSTS/H1/MC1/SAGM2/Data/dampRegress_H1SUSMC1_M2_1449002022_720.mat
r12828
M3
Results:
$sussvn/HSTS/H1/MC1/SAGM3/Results/allDampRegressCompare_H1SUSMC1_M3_NoiseComparison_1442005989vs1449002022-720.pdf
$sussvn/HSTS/H1/MC1/SAGM3/Results/allDampRegressCompare_H1SUSMC1_M3_1442005989vs1449002022-720.mat
Data:
$sussvn/HSTS/H1/MC1/SAGM3/Data/dampRegress_H1SUSMC1_M3_1442005989_720.mat
$sussvn/HSTS/H1/MC1/SAGM3/Data/dampRegress_H1SUSMC1_M3_1449002022_720.mat
r12829

MC2
M2
Results:
$sussvn/HSTS/H1/MC2/SAGM2/Results/allDampRegressCompare_H1SUSMC2_M2_NoiseComparison_1442007133vs1449002143-540.pdf
$sussvn/HSTS/H1/MC2/SAGM2/Results/allDampRegressCompare_H1SUSMC2_M2_1442007133vs1449002143-540.mat
Data:
$sussvn/HSTS/H1/MC2/SAGM2/Data/dampRegress_H1SUSMC2_M2_1442007133_540.mat
$sussvn/HSTS/H1/MC2/SAGM2/Data/dampRegress_H1SUSMC2_M2_1449002143_540.mat
r12833
M3
Results:
$sussvn/HSTS/H1/MC2/SAGM3/Results/allDampRegressCompare_H1SUSMC2_M3_NoiseComparison_1442007133vs1449002143-540.pdf
$sussvn/HSTS/H1/MC2/SAGM3/Results/allDampRegressCompare_H1SUSMC2_M3_1442007133vs1449002143-540.mat
Data:
$sussvn/HSTS/H1/MC2/SAGM3/Data/dampRegress_H1SUSMC2_M3_1442007133_540.mat
$sussvn/HSTS/H1/MC2/SAGM3/Data/dampRegress_H1SUSMC2_M3_1449002143_540.mat
r12834

MC3
M2
Results:
$sussvn/HSTS/H1/MC3/SAGM2/Results/allDampRegressCompare_H1SUSMC3_M2_NoiseComparison_1442005989vs1449002022-720.pdf
$sussvn/HSTS/H1/MC3/SAGM2/Results/allDampRegressCompare_H1SUSMC3_M2_1442005989vs1449002022-720.mat
Data:
$sussvn/HSTS/H1/MC3/SAGM2/Data/dampRegress_H1SUSMC3_M2_1442005989_720.mat
$sussvn/HSTS/H1/MC3/SAGM2/Data/dampRegress_H1SUSMC3_M2_1449002022_720.mat
r12830
M3
Results:
$sussvn/HSTS/H1/MC3/SAGM3/Results/allDampRegressCompare_H1SUSMC3_M3_NoiseComparison_1442005989vs1449002022-720.pdf
$sussvn/HSTS/H1/MC3/SAGM3/Results/allDampRegressCompare_H1SUSMC3_M3_1442005989vs1449002022-720.mat
Data:
$sussvn/HSTS/H1/MC3/SAGM3/Data/dampRegress_H1SUSMC3_M3_1442005989_720.mat
$sussvn/HSTS/H1/MC3/SAGM3/Data/dampRegress_H1SUSMC3_M3_1449002022_720.mat
r12831

PR3
* Not really important for these lower stages, but still wanted to note that the state of the estimator was that during the before time, P and Y were on, and and during the after time, only Y was on, and these times weren't during any of the times were we were seeing issues with the estimator damping.
M2
Results:
$sussvn/HLTS/H1/PR3/SAGM2/Results/allDampRegressCompare_H1SUSPR3_M2_NoiseComparison_1444913610vs1445321359-1200.pdf
$sussvn/HLTS/H1/PR3/SAGM2/Results/allDampRegressCompare_H1SUSPR3_M2_1444913610vs1445321359-1200.mat
Data:
$sussvn/HLTS/H1/PR3/SAGM2/Data/dampRegress_H1SUSPR3_M2_1444913610_1200.mat
$sussvn/HLTS/H1/PR3/SAGM2/Data/dampRegress_H1SUSPR3_M2_1445321359_1200.mat
r12836
M3
Results:
$sussvn/HLTS/H1/PR3/SAGM3/Results/allDampRegressCompare_H1SUSPR3_M3_NoiseComparison_1444913610vs1445321359-1200.pdf
$sussvn/HLTS/H1/PR3/SAGM3/Results/allDampRegressCompare_H1SUSPR3_M3_1444913610vs1445321359-1200.mat
Data:
$sussvn/HLTS/H1/PR3/SAGM3/Data/dampRegress_H1SUSPR3_M3_1444913610_1200.mat
$sussvn/HLTS/H1/PR3/SAGM3/Data/dampRegress_H1SUSPR3_M3_1445321359_1200.mat
r12835

SR3
M2
* This comparison is useless because there seems to have been something wrong with the 'old' satamp, S1100105. See 88706 for more info
Results:
$sussvn/HLTS/H1/SR3/SAGM2/Results/allDampRegressCompare_H1SUSSR3_M2_NoiseComparison_1443025894vs1445809419-1200.pdf
$sussvn/HLTS/H1/SR3/SAGM2/Results/allDampRegressCompare_H1SUSSR3_M2_1443025894vs1445809419-1200.mat
Data:
$sussvn/HLTS/H1/SR3/SAGM2/Data/dampRegress_H1SUSSR3_M2_1443025894_1200.mat
$sussvn/HLTS/H1/SR3/SAGM2/Data/dampRegress_H1SUSSR3_M2_1445809419_1200.mat
r12839
M3
* Not really important for these lower stages, but still wanted to note that for the before time, no estimators were on, and during the after time, only the Y estimator was on
Results:
$sussvn/HLTS/H1/SR3/SAGM3/Results/allDampRegressCompare_H1SUSSR3_M3_NoiseComparison_1443025894vs1445565979-1200.pdf
$sussvn/HLTS/H1/SR3/SAGM3/Results/allDampRegressCompare_H1SUSSR3_M3_1443025894vs1445565979-1200.mat
Data:
$sussvn/HLTS/H1/SR3/SAGM3/Data/dampRegress_H1SUSSR3_M3_1443025894_1200.mat
$sussvn/HLTS/H1/SR3/SAGM3/Data/dampRegress_H1SUSSR3_M3_1445565979_1200.mat
r12837

Ops Day Shift Summary

TITLE: 01/08 Day Shift: 1530-0030 UTC (0730-1630 PST), all times posted in UTC
STATE of H1: Planned Engineering
INCOMING OPERATOR: None
SHIFT SUMMARY: More progress today on HAM7 beam alignment and with JAC install in HAM1, which is now in-place on the ISI.
LOG:

Start Time	System	Name	Location	Lazer_Haz	Task	Time End
17:16	SAF	LASER HAZARD	LVEA	YES	LVEA IS LASER HAZARD	Ongoing
17:39	JAC	Rahul	LVEA	Y	JAC installation	20:32
17:47	FAC	Kim	MX	N	Technical cleaning	18:29
17:48	JAC	Masayuki	LVEA/Opt Lab	Y	JAC installation	20:32
17:54	JAC	Jennie	LVEA	Y	JAC installation	18:48
17:57	JAC	Jason	LVEA	Y	JAC installation	20:32
18:26	JAC	Betsy	LVEA	-	Check in with JAC team	19:26
18:00	VAC	Norco	MX	N	LN2 fill	18:52
18:32	JAC	Kar Meng	Opt Lab	N	Looking for parts	18:35
18:35	SAF	Richard	LVEA	-	Safety checks	18:48
18:41	VAC	MikeL, MikeZ, Dolly, Lorna, others	LVEA	-	LVEA tour	19:39
18:47	SEI	Jim	EX, EY	N	Wind fence inspections	20:00
18:57	JAC	Jennie	LVEA	Y	JAC installation	20:32
21:39	CDS	Fil, Marc	LVEA	-	HAM1 cabling planning	22:16
22:07	JAC	Jennie, Jason, Masayuki	LVEA	Y	JAC installation	00:27
22:29	JAC	Betsy	LVEA	Y	JAC installation	23:29
22:29	SQZ	Kar Meng	LVEA	Y	HAM7 SQZ alignment	00:04
22:31	SQZ	Sheila, Elenna	LVEA	Y	HAM7 SQZ alignment	00:03
22:35	JAC	Rahul	LVEA	Y	JAC installation	00:27
22:36	JAC	Rick	LVEA	-	JAC installation checkin	23:36
23:06	VAC	Jordan	LVEA	-	Looking for parts	23:19
23:41	SAF	Richard	LVEA	-	Safety checks	00:00

OPO transmission clipping hunt continued...

[Sheila, Elenna, Karmeng]

Measured optical power (with power meter) of 0.89~0.9mW out of the OPO, 0.89~0.9mW after the first transmission through SFI1, 0.85mW (roughly 4.5%) after the reflection off filter cavity, and 0.84~0.85mW on SQZT7 first periscope.

We placed a photodiode right after second periscope on SQZT7 for diagnostic purpose.

 

JAC input periscope and JM1 installation

[Jennie, Jason, Rahul, Betsy, Masayuki]

Betsy monitored the particle count throughout the work, and it remained below 20 at all times.

Summary:

The input periscope was installed and aligned. Minor First Contact issues on the top mirror required a mirror swap with the output periscope, after which installation proceeded smoothly. The periscope height and rotation were adjusted to center the beam on both mirrors and meet the 90° ± 5° rotation requirement with sufficient margin. JM1 was subsequently installed using target irises.

Work Details

• Aligned the beam to the HAM1 irises. The bottom mirror of the periscope was used to align the first iris, and the top mirror was used for the second iris. Initially, the beam was hitting the left edge of the iris; after several iterations of beam walking, both irises were well aligned.

• During removal of the first First Contact (FC) on the top mirror of the periscope, we found a small piece of FC residue remaining on the mirror surface. We attempted to remove it by scrubbing, but it could not be removed. Therefore, we decided to reapply FC to this mirror. The periscope was removed from the chamber and placed on a clean tray. Jennie and Betsy applied FC to the HR surface of the top mirror. The second FC attempt was also unsuccessful, so to continue the work without waiting for FC drying, we decided to swap this mirror with the top mirror from the output periscope, which will be installed later. The mirror taken from the output periscope was successfully cleaned, and the FC peeled off properly.

• At the time of the first FC attempt, the target irises for periscope alignment were placed. The first picture shows the two target irises. Each iris was aligned to the corresponding hole line. I measured the distance from the hole line as shown in the second and third pictures. The iris was placed approximately three-quarters of the way from the hole line. (In one of the pictures, the hole is difficult to see, but it is located beneath the 4-inch tick mark on the ruler.) Before placing these irises in the HAM1, the height was also adjsuted with rulere to 4".

• After positioning the periscope at its nominal designed location, we found that adjustment of the top mirror height was required. The periscope includes a vertical slot to accommodate different beam heights from the PSL at the two sites. The top mirror was moved to the highest position within the slot, which provided the best alignment for the beam to hit the center of both mirrors.

• The output beam from the periscope was aligned by translating and rotating the periscope body itself. The rotation angle needed to be 90 degrees within a tolerance of ±5 degrees. As discussed below, this requirement was satisfied with margin.

• The top mirror of the output periscope was also hung in the same manner as the input periscope, providing an appropriate output beam height.

• After completing the periscope installation, JM1 was installed. Target irises were again used for alignment, and JM1 was positioned using these references. Details of this installation will be reported separately by Rahul.

 

Rotation angle discussion

• The beam line from the PSL was projected onto the ISI table by measuring the iris positions that were placed at the beginning of this installation period (see earlier alog). The first iris (closer to the PSL) was positioned 1-3/8″ from the −Y hole line, while the second iris was 1-5/16″ from the same reference. The two irises are separated by approximately 48″, indicating that the beam has an angle toward the −Y direction of (1/16) / 48 = 0.0013 rad.

• The beam from the periscope was aligned using two irises separated by 20″. Assuming the irises are parallel to the hole line and that the alignment accuracy is limited by the iris aperture size (~1 mm), the beam is parallel to the hole line within 1mm / 20″ = 0.0019 rad

• Combining these effects, the total error of the rotation angle of the beam about the z-axis is less than 5 mrad even in the worst-case scenario. The requirement for this rotation angle is 90 degrees ± 5 degrees (±87 mrad), so the alignment meets the requirement with a safety margin of approximately a factor of 10.