First alignement of the Koheras with the FP cavity, posted by Ronic Chiche at Other about lasers and optics
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today with Manar, we brought the Koheras to the Minicav optical room and aligned it with the Iris used for the cavity.
but if I properly understood what Manar said to me, the cavity mirrors have been moved by roughly 1cm after Daniele and Manar finished the alignment.
with what we saw today, it seems the cavity is not aligned anymore.... we will check that tomorrow with Daniele. |
First alignement of the Koheras with the FP cavity, posted by Ronic Chiche at Other about lasers and optics
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We changed the mirrors position back to the original reference (0, 0, 0, 0) for all mirrors, but the alignment could not be found.
The
course of action will be :
- abandon the alignment done previously with Helium Neon Laser |
Vacuum and locking tests, posted by Ronic Chiche at Optical room about lasers and optics | vacuum 
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Today, the vacuum pressure inside the Minicav was good : 7.8e-6 mbar
the Gauge model is a Leybold PTR 90N => see picture for details
surprisingly, the same gauge connected to the TurboVac SL 80 was not read with the same value (see pictures) |
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Installation of referance plate (installation plaque de référence), posted by Manar Amer at Other about mechanics
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************************** The work in this report is done in the Minicavity clean room ***************************
Location: Minicavity Clean Room
On 14/01/2021
Installation of the minicavity base (reference plate) (First attempt)
People: |
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referance plate position adjestment , posted by Manar Amer at Other about mechanics
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The reference plate position was adjusted;
- previously: the side facing us (where the plane mirrors are located), the distance between plane mirrors was smaller than spherical.
- now: its position was reversed, the distance between the plane is grater than spherical. |
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Mirrors Mounts , posted by Manar Amer at Other about mechanics
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The minicavity mirror mounts are located in the preparation room before the clean room in the cupboard.
There are three mounts and two primary mounts for the mounts to be placed on.
Need another one to have a set of four --→ They are made specifically by the lab, order extra one |
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Mirrors Damage , posted by Manar Amer at Other about lasers and optics
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The mirrors have what seems to be damage spots on them
To be investigated after finishing the alignment
attached a picture of the mirror (To show the mirror size scale) |
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Spare Mirrors , posted by Manar Amer at Other about lasers and optics
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There are spare mirrors placed in the preparation room of the minicavity
the exact number to be investigated
approx ~ 12 -→ 9 of them are injection |
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Screws Length , posted by Manar Amer at Other about mechanics
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Specific length (5 mm) for the screws used to fix the mirrors and the irises in the cavity box
need to search for extra, don't have enough
the amount needed (3 x 4 = 12) at least, each mirror is fixed with three screws |
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Mirrors closely backed when Fixed , posted by Manar Amer at Other about mechanics
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As shown in the image attached when placing the mirror mounts (or irises) of the very close mirrors on the mounts they hit each other.
The motor's location needs to be changed for them not to hit each other (pushed a little to the back or the front)
This restricts the motion of the motors later on. |
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Mirrors closely backed when Fixed , posted by Manar Amer at Other about mechanics
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The mirrors were placed in the wrong orientation, it was adjusted correctly
but the issue of having the mirrors/irises hitting each other was still there.
The motors need to be moved in the longitudinal position to avoid this issue. |
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Mirrors closely backed when Fixed , posted by Manar Amer at Other about mechanics
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Throughout all the range of motion for the motors
-→ no problem with the mirrors close together (M1-M3 and M2-M4) hitting each other.
-⇾ the problem with the pinholes hitting each other was fixed by trimming their edges a little, no issue for M1-M3 and M2-M4 now. |
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Telescope to match Koheras with minicav, posted by Manar Amer at Other about lasers and optics
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The beam waist of the Koheras CW laser after the collimater is bigger than the Waist required for injection inside the cavity at M1.
A Telescope is to be made to match the two beams.
Details will be added ...... |
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Telescope to match Koheras with minicav, posted by Manar Amer at Other about lasers and optics
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The telescope to adjust the beam size was made only using one lens with very long focal length (1 meter)
it is placed a distance of 40 cm from the collimeter and 1 meter from the center of the beam waist between the planar mirrors.
This way the two beam (of laser and cavity) have the shape when they propagate |
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vacuum Joint installed, posted by Manar Amer at Other about mechanics | vacuum
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| The placement of the new ordered optical joint for the minicav |
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Optical Windows installed, posted by Manar Amer at Other about mechanics | lasers and optics
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A new optical window was installed in place of the old broken one (it was broken from the sides, a sign there might have been a leakage before !!! )
The old broken window is placed in a container in SAS room in the gray cupboard titled "old window broken on the side"
The one changed is the output window behind M2 and M4 |
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Mirrors Mounts , posted by Manar Amer at Other about mechanics
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Update, they are received and the order is logged in MINICAV orders
Mounts placed in SAS cupboard
Manar |
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Minicav Updated SetUp , posted by Manar Amer at Optical room about mechanics | lasers and optics | detectors and electronics | cabling
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Enclosed is the current setup of the minicavity
** made by Fred |