Differences between revisions 2 and 6 (spanning 4 versions)

Angular Sensing and Control (Oct, 2022)

Contents

Angular Sensing and Control (Oct, 2022)
Next Steps
Known issues

WFS ports

REFL (17, 45 MHz)

Optical layout
- https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9238
- Same as O3GK
PZT1, PZT2, and REFL_WFS picomotors are available to center the beam on REFL_WFS1 and REFL_WFS2

POP (17, 45 MHz)

Optical layout
- https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9623
- POP WFSs were newly installed after O3GK
POP-S and POP-P cameras are available

AS (17, 28 MHz)

Optical layout
- https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9817
- Mostly same as O3GK
PZT1, PZT2, and AS_WFS picomotors are available to center the beam on AS_WFS1 and AS_WFS2
AS and OMC_TRANS CCDs are available
OMC_REFL CCD hasn't been connected

DC QPD ports

TMSY

TMSY QPD1 and 2 are placed on the TMSY in-air table, with 90 degrees separated in Gouy phase
QPD1 is used to steer the beam from BS (ASC DOF1 is the TMSY QPD loop feeding back to the BS)
Beam profile
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22479
No PIT-YAW coupling
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22575

TMSX

There is only one DC QPD installed on the TMSX in-air path. At a random Gouy phase position.
The beam is NOT centered on the DC QPD when the X-arm is locked, but the X-arm alignment may have changed since then.
TMSX in-air table power budget
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22310
The in-air beam is extremely astigmatic
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22221
There are strong PIT-YAW coupling depending on the position of the beam
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22228
- Matteo-san's previous measurement did not show a strong coupling. It seems to depend on the position of the DC QPDs.
  - https://klog.icrr.u-tokyo.ac.jp/osl/?r=20263

POP Forward

There are two DC QPDs on POP Forward, used for the initial alignment

DC PDs

There are POP_P and POP_S DC PDs on POP.

WFS Commissioning

WFS DC centering

Open the REFL shutter for REFL WFS
Beam spots on the quadrant diodes must be centered (DC centering)
- PZTs and picomotors are available

Single Y arm

Sensing matrix
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22578
Input matrix
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22602
Loops closed
- https://klog.icrr.u-tokyo.ac.jp/osl/?r=22671
- DSOFT is IY, DHARD is EY
Loops or noise haven't been characterized
No offsets were necessary on the sensors

Single X arm

PRMI

PRFPMI

DRFPMI

Next Steps

Infrastructure

Guardian implementation
- DC centering loops on REFL, POP, and AS
- Single Y, X arms, and PRMI guardstates for initial alignment
Add trigger for the main ASC switch (K1:ASC-WFS_GAIN) similarly to the IMC switch (K1:IMC-WFS_GAIN)

Simulation

Compare the measured sensing matrices against the simulation
- Koyama-kun's simulation GUI tool is available on the workstations
  - sitemap > Commissioning Top > finesse GUI

Integration

Implement single-Y, single-X, and PRMI controls for the initial alignment
- If the alignment is too off, first ADS then WFS control?
PRFPMI/DRFPMI angular controls
Noise budget

Known issues

TMSX PIT-YAW coupling
- The beam is slightly not centered in yaw on the second lens on the in-air table. Adjusting the beam position on the lens might fix the problem.

KAGRA/Subgroups/MIF/AngularSensing (last edited 2022-11-02 09:12:15 by KeikoKokeyama)

-  ⇤ ← Revision 2 as of 2022-10-26 09:02:28 → 
  Size: 1671
  Editor: KeikoKokeyama
  Comment:
+   ← Revision 6 as of 2022-10-26 10:42:07 → ⇥
  Size: 3662
  Editor: KeikoKokeyama
  Comment:
-Deletions are marked like this.
+Additions are marked like this.
 Line 1:
-= Angular Sensing and Control (2022) =
+= Angular Sensing and Control (Oct, 2022) =

<<TableOfContents()>>
-Line 8:
+Line 10:
+  * Same as O3GK
-Line 14:
+Line 17:
+  * POP WFSs were newly installed after O3GK
-Line 19:
+Line 23:
-  *
+  * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9817
  * Mostly same as O3GK
-Line 28:
+Line 33:
+ * QPD1 is used to steer the beam from BS (ASC DOF1 is the TMSY QPD loop feeding back to the BS)
-Line 34:
+Line 40:
+ * There is only one DC QPD installed on the TMSX in-air path. At a random Gouy phase position.
 * The beam is NOT centered on the DC QPD when the X-arm is locked, but the X-arm alignment may have changed since then.
 * TMSX in-air table power budget
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22310
 * The in-air beam is extremely astigmatic
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22221
 * There are strong PIT-YAW coupling depending on the position of the beam
  * https://klog.icrr.u-tokyo.ac.jp/osl/?r=22228
  * Matteo-san's previous measurement did not show a strong coupling. It seems to depend on the position of the DC QPDs.
   * https://klog.icrr.u-tokyo.ac.jp/osl/?r=20263
-Line 38:
+Line 54:
+== DC PDs ==
 * There are POP_P and POP_S DC PDs on POP.
-Line 39:
+Line 58:
-Line 53:
+Line 73:
- * Loops or noise haven't been characterized
+ * Loops or noise haven't been characterized
 * No offsets were necessary on the sensors
-Line 65:
+Line 86:
+= Next Steps =
== Infrastructure ==
 * Guardian implementation
  * DC centering loops on REFL, POP, and AS
  * Single Y, X arms, and PRMI guardstates for initial alignment
 * Add trigger for the main ASC switch (K1:ASC-WFS_GAIN) similarly to the IMC switch (K1:IMC-WFS_GAIN)
== Simulation ==
 * Compare the measured sensing matrices against the simulation
  * Koyama-kun's simulation GUI tool is available on the workstations
   * sitemap > Commissioning Top > finesse GUI
== Integration ==
 * Implement single-Y, single-X, and PRMI controls for the initial alignment
  * If the alignment is too off, first ADS then WFS control?
 * PRFPMI/DRFPMI angular controls
 * Noise budget

= Known issues =
 * TMSX PIT-YAW coupling
  * The beam is slightly not centered in yaw on the second lens on the in-air table. Adjusting the beam position on the lens might fix the problem.