 Thu Jul 20 14:14:49 2023, Thejas , Optics, General, A+ OMC bonding template alignment 
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We aligned the bonding template onto the glass braedboard. This was done with the help of a vernier caliper and adjusting teh peek screws at the edge
of the templates to make sure that the gap between the breadboard and template edges are equal for each pair of opposite sides.
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 Thu Aug 3 10:31:55 2023, Thejas, Optics, General, A+ OMC build: beam spot positions
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Quote:
Yesterday, we measured |
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Mon Feb 27 17:40:27 2023, Thejas , Optics, Characterization, A+ OMC curved mirror characterization
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[Camille, Stephen, Thejas]
Today, before the ZYGO lab was cleaned and prepared for the cureved mirrors' radius of curvature (ROC) characterization, Mirror no. 6 was
mounted into one of the half inch mirror holders. The cleanliness of the envoronment and handling was not satisfactory. Tomorrow efforts will |
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Wed Mar 1 10:23:10 2023, Thejas , Optics, Characterization, A+ OMC curved mirror characterization
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[Camille, Thejas, Stephen]
Yesterday, efforts were made to measure ROC of curved mirrors (#6) in the ZYGO lab using a Fizeau Interferometer. Peculiar observation: Stray
fringes were seen that dominated the fringes that conformed with the expectation. The origin of these fringes is still not accounted for (see attached |
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Tue Mar 14 10:41:06 2023, Thejas , Optics, Characterization, A+ OMC curved mirror characterization
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[Camille, GarriLynn, Stephen, Thejas]
Folllowing the replacement of the spherical transmission / reference mirror with a flat mirror, on Friday we were able to observe fringes that
facilitated characterization of the curvature minimum. |
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Tue Mar 14 12:12:41 2023, Koji , Optics, Characterization, A+ OMC curved mirror characterization
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RoC: 2.65m ! Interesting. I'll wait for the follow-up analysis/measurements. The RoC may be dependent on the area (diameter) for the fitting. You
might want to run the fitting of your own. If so, let me know. I have some Matlab code that is compatible with the CSV file exported from MetroPro data. |
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Fri Mar 10 10:23:08 2023, Thejas, Optics, Characterization, A+ OMC curved mirror radius of curvature
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OMC test set-up
Yesterday, laser beam output from the fibre follwoing teh mode-matching lenses was picked off and beam profile was characterized using beam profiler Thorlabs
BP209-VIS. |
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Thu Jul 20 14:28:53 2023, Thejas , Optics, General, A+ OMC optic bench beam layout
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Beam profile of the input beam was measured at it's beam waist, this is to ensure the input beam waist matches the cavity beam waist (mode-matching)
- ref attachement 2
w_0x: 456.47032902662903 +/- 1.4466927709703827 um
z_0x: 0.35828846919253937 +/- 0.008323313108283267 m
w_0y: 495.1490367020396 |
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Fri Jul 21 03:29:30 2023, Koji , Optics, General, A+ OMC optic bench beam layout
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Nice measurement. This result suggests that the fiber mode is supposed to be matched to the OMC cavity by 99.8% at z0=0.358 m. Note that the OMCmode
has a waist radius of 0.4896 mm and 0.4905 mm for the horizontal and vertical modes, respectively.
In reality, the fiber mode contains higher-order HG modes. Therefore the actual mode matching will be limited to ~98%. |
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Wed Feb 15 17:40:21 2023, Thejas , Optics, Characterization, A+ OMC perpendicularity of hole prisms 20x
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[Camille, Stephen, Thejas]
Contnuing the efforts to measure and check perpendicularity: tombstone prisms with holes/ hole prisms (HP).
Note: Veritcal crosshair splitting can be seen in the some of the image. This is probably because the horizontal of the Al flat |
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Sat Jul 29 12:05:52 2023, Thejas , Optics, General, A+ OMC unit 1 build: Resonance achieved
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[Camille, Thejas]
Steps followed to acheive this resonance:
1. Make sure the input beam is roughly aligned to the center of the flat mirrors (FMs). The height of the beam should be roughly the height |
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Tue Jul 25 23:39:07 2023, Thejas, Optics, General, A+ OMC unit 1: CM positions swapped
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With CM #30 at CM1 position and CM #14 at CM2 postion, when the beam spot on the CM1 is a little lower than the central line the spot position on the
CM2 is higher. This not expected given that the ROC of these mirrors is large. We swapped the position of these mirrors and the spot positons on these
CMs is not consistent i.e. whne the spot on CM1 is lower the same is true for CM2. But we see that the first reflection spot from FM1 is higher than |
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Thu Jul 13 01:02:58 2023, Stephen, Optics, General, A+ OMC, Bonding of Curved Mirror Batch 1 16x
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[2023.07.13 - Stephen, Camille, Thejas, Maria]
We bonded Curved Mirror assemblies today. Some notes about this log entry:
Thejas will post a log discussing matching.
This log hosts a subset of the photos posted to the A+ |
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Thu Jul 13 00:38:47 2023, Stephen, Optics, Characterization, A+ OMC, PZT DC Response and Length to Angle before Curved Mirror Assy Batch 1
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[2023.07.13]
The attached table includes the characterization values used to inform the matches for the first four units, Curved Mirror Assy Batch 1.
Thejas prioritized the matches using these insights. Some notes: |
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Wed Feb 8 16:10:52 2023, Stephen, Optics, Characterization, A+ OMC, Parallelism of HR Prisms 7x
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[Camille, Thejas, Stephen]
We set up the white light autocollimator in the Downs B119 cleanroom. (Nippon Kogaku, from Mike Smith).
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Thu Feb 9 15:54:41 2023, Thejas , Optics, Characterization, A+ OMC, Parallelism of HR Prisms 19x
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[Camille, Thejas, Stephen]
Continuing yesterday's efforts to measure the wedge angle of the back surface of the prisms. We completed measurement for all the 18 prisms.
The images below accompanying the readings represent the S2 crosshair image on top of the reticle, alighned for yaw. |
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Tue Jul 18 17:34:45 2023, Thejas, Optics, General, A+ PZT sub-assemblies
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[Camille, Thejas]
Post sub-assembly bonding of CM : Madeline will post a separate update on the Oven temperature profile.
The subassemblies were taken out of the oven. The bonding fixture plates were carefully taken apart, sub-assembly #1 involving curved mirror |
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Wed Jul 19 14:26:17 2023, Koji, Optics, General, A+ PZT sub-assemblies
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| Pens like Sharpie are not recommended to be used for CLASS B parts. |
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Fri Jul 21 00:23:35 2023, Thejas , Optics, General, A+ PZT subassembly glue sheets
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| Below are the gluesheets for the first four PZT subassembly bonding. |
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Thu Aug 3 15:15:29 2023, Thejas, Optics, General, A+OMC mode-matching efficiency
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The cavity falls out of lock very often when subjected to slight movements of objects on the optic table. On Wednesday, we tried
to bring the cavity back to resonance when one of the curved mirrors' position was slightly disturbed. And now the reflected cavity power is higher
than that achieved on Tuesday (see below). This means mode-matching efficiency is about 96.5%. The laser control signal and reflected PD signal also seem noiser |
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Thu Aug 3 15:24:28 2023, Koji, Optics, General, A+OMC mode-matching efficiency
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The amount of the reflected beam is a function of the mode matching and the cavity loss.
- The noise could show up larger when the PDH lock has the error offset. Try to tune the input offset knob (which has no knob dial ;) ) to minimize |
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Mon Jul 25 18:25:04 2022, Koji, General, General, A/C Filter was replaced
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New filter PN
Grainger
TK70457312T Mini-Pleat Air Filter, Style - Air Filters Box, Performance Rating MERV 14, Nominal Filter Size 12x24x2
Previous |
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Fri Apr 5 18:18:36 2013, Zach, Optics, Configuration, AOM probably broken
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Quote:
Then, I started to check the AOM path. I noticed that the 1st (or -1st) order beam is very weak. |
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Mon Apr 1 10:28:03 2013, Koji, Mechanics, General, Additional UV blast for the top surface
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[Koji, Lisa, Jeff, Zach]
Jeffs concern after talking with the glue company (EMI) was that the UV blast for the top side was not enough. |
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Fri Apr 19 09:35:28 2019, Joe, General, , Adjusting cavity axis, re-alignment of OMC and locking
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[koji,philip, joe, liyuan, steven]
*still need to add photos to post*
PZT 11 was removed and inspected for so dust/dirt on the bottom of the prism. We saw a spot. We tried to remove this with acetone, |
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Mon Nov 13 23:57:55 2023, Koji, Electronics, Loan / Lending, Agilent 4395A Network Analyzer -> WB251
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Aidan and Hanna wanted to use the Agilent 4395A Network Analyzer at the WB251.
All the connections were removed. Unrelated units including an HP FFT analyzer and the Linux PC were also removed. |
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Fri Apr 12 09:25:31 2013, Koji, Optics, Characterization, Alignment of the OMC (without glue)
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[Zach Koji]
The first attempt not to touch the curved mirrors did not work. (Not surprising)
The eigenmode is not found on the mirror surface. |
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Thu May 9 17:35:07 2019, Koji, Optics, General, Alignment strategy
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Notes on the OMC cavity alignment strategy
- x3=1.17 γ + 1.40 δ, x4=1.40 γ + 1.17 δ
- This means that the effect of the two curved mirrors (i.e. gouy phases) are very similar. To move x3 and x4 in common is easy, but to do differentially |
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Mon Jun 23 21:54:16 2014, Koji, Optics, General, All of the gluing completed
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The bottom-side templates were removed.
The last beam dump was removed
TODO |
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Fri Jun 20 18:59:12 2014, Koji, Optics, General, All of the invar blocks have been glued
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All of the INVAR blocks have been glued.
I found thinner shims in the stock.
On Monday, the template will be removed. |
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Thu Jun 19 23:16:50 2014, Koji, Optics, General, All of the prisms have been glued
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- All of the PRISM mirrors have been glued
- 4 out of 5 beam dumps have been glued
TODO |
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Fri Jan 18 13:25:17 2013, Koji, Optics, Configuration, Autocollimator calibration
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An autocollimator (AC) should show (0,0) if a retroreflector is placed in front of the AC.
However, the AC may have an offset. Also the retroreflector may not reflect the beam back with an exact parallelism.
To calibrate these two errors, the autocollimator is calibrated. The retroreflector was rotated by 0, 90, 180, 270 deg |
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Wed Jan 16 14:10:50 2013, Koji, Optics, Characterization, Autocollimator tests of optics perpendicularity/parallelism
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The items:
- Autocollimator (AC) borrowed from Mike Smith (Nippon Kogaku model 305, phi=2.76", 67.8mm)
- Retroreflector (corner cube) |
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Sat Mar 26 18:22:24 2016, Koji, Electronics, Characterization, Baking / Contamination tests of the PDs
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For the production of the aLIGO PDs, the following transfer of the PDs were carried out
A1-23 Cage A1 -> G1
A1-25 Cage A2 -> G2 |
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Tue Apr 5 18:22:40 2016, Koji, Electronics, Characterization, Baking / Contamination tests of the PDs
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Possible reduction of the QE was observed after air-bake at 75degC.
Yesterday I received Cage G from Bob for intermediate test of the PD performance after air bake but before vacuum bake.
This cage was prepared to be the production pair. |
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Wed Jul 2 18:58:42 2014, Koji, General, General, Beam dump delamination
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While the OMC breadboard was being inspected, it was found that two out of five black-glass beam dumps showed sign of delamination.
(attached photos).
The base of the each beam dump is a fused silica disk (25mm dia.). The black glass pieces are bonded to the disk. The bond is EP30-2 |
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Thu Jul 3 17:45:18 2014, Koji, General, General, Beam dump delamination
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Here is the resolution.
I'll apply fillets of EP30-2 along the edges of the black glass (See figure).
In order to allow the air escape from the gap, the inside of the V will not be painted. |
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Fri Mar 29 08:55:00 2013, Zach, Optics, Configuration, Beam launched into fiber
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Quote:
Lisa and I concurred that it felt like we had converged to the optimum alignment and polarization, which would mean that the lack of |
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Thu Apr 4 23:44:52 2013, Koji, Optics, Configuration, Beam launched into fiber
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We had to move our flipper mirror to share the beam between Peter's setup and ours as our flipper is at the place where the ISS PD array base is supposed
to be!
There was no place to insert the flipper in the setup. We (Peter and Koji) decided to move the laser back for ~2". |
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Fri Dec 6 00:55:25 2019, Koji, Optics, General, Beamdump gluing 6x
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[Stephen, Koji]
20 glass beamdumps were bonded at the 40m cleanroom.
Attachment 1: We had 20 fused silica disks with a V-groove and 40 black glass pieces |
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Sat Mar 23 02:41:00 2013, Koji, Optics, General, Black glass beam dumps for the first OMC
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Received black glass beam dumps from MIT
- gluing by EP30-2 looks pretty fine. Enough sturdy.
- some gap visible between the glass => incident angle should be considered so that the first beam does not exit from the gap |
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Sat Jul 1 15:29:57 2017, Koji, Optics, General, Black glass cleaning / Final bonding for the emergency repair for OMC #002
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[Alena, Koji]
Report of the work on June 30.
1. Cleaning of the black glass beam dumps |
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Thu Jul 21 14:35:35 2022, Koji, General, General, Bond reinforcement blocks for the invar brackets
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Bond reinforcement blocks for the invar brackets:
Attachment 1: CLASS A glass prisms (the surplus of the 2016 repair)
Attachment 2: Dirty
reiforcement bars made of Aluminum
There are also many dirty prisms in the kit obtained from Stephen
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Wed Apr 26 14:43:44 2023, Stephen, General, Loan / Lending, Borrowed Items for PZT DC Response Shadow Sensor Setup
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Borrowed for PZT DC Response Shadow Sensor Setup (see Attachment 1):
Thorlabs PDA100A Photodiode (and power supply)
Thorlabs MDT694B Piezo Driver
Current Location: Downs 227 |
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Fri May 12 10:00:06 2023, Camille Makarem, General, Loan / Lending, Borrowed Items for PZT DC Response Shadow Sensor Setup
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The ThorLabs MDT694B piezo driver was returned to the OMC lab.
Quote:
Borrowed for PZT DC Response |
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Tue Oct 22 15:54:59 2019, Koji, Electronics, Loan / Lending, Borrowed LB1005 from Cryo Cav
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From Cryo Cav setup
Borrowed LB1005 Servo box -> OMC
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Tue Apr 16 23:11:43 2019, Koji, General, General, Borrowed items from the other labs
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Apr 16, 2019
Borrowed two laser goggles from the 40m. (Returned Apr 29, 2019)
Borrowed small isopropanol glass bottole from CTN. |
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Thu May 3 21:45:58 2018, awade, General, Loan / Lending, Borrowed toaster oven
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| I’ve borrowed the black and decker toaster oven to dry some sonicated parts. It is temporarly located in the QIL lab. |
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Fri Jul 22 17:47:38 2022, Koji, General, General, C&B request for the reinforcement blocks
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OMC Reinforcement blocks
1. P/N D1600316; Version v4; Type 01; Qty 30; Source Chemistry Machine Shop
2. P/N D1600316; Version v4; Type 02; Qty 15; Source Chemistry Machine Shop |
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Thu May 23 01:42:46 2019, Koji, Optics, Characterization, C30665 high power test
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An Excelitas C30665 PD with the cap removed (SN07 in Case H slot #2) was exposed to the beam with the optical power of 1.4mW to 334mW.
After each illumination, the dark current and the dark noise level were tested. Also the photo image of the PD surface was taken each time.
- No significant change of the dark current after each illumination. |