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= Angular Sensing and Control (2022) = = Angular Sensing and Control (Oct, 2022) =

<<TableOfContents()>>
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  * Same as O3GK
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  * POP WFSs were newly installed after O3GK
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  *   * https://gwdoc.icrr.u-tokyo.ac.jp/cgi-bin/private/DocDB/ShowDocument?docid=9817
  * Mostly same as O3GK
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=== TMSX ===
 * There is only QPD2 ({{{K1:TMS-X_IR_QPDA2_{PIT,YAW}}}}) on the TMSX in-air path. At a random Gouy phase position.
 * The beam was sent to the QPD2 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
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 * QPD1 is used to the beam position control feeding back to the BS ({{{K1:ASC-DOF1_{P,Y}}}})
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=== TMSX ===
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== DC PDs ==
 * There are POP_P and POP_S DC PDs on POP.
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 * Open the REFL shutter for REFL WFS ==== General ====
 * If the beam is off, use the picomotor first because the PZT ranges are not large
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==== REFL ====
 * Open the REFL shutter first for REFL WFS
 * {{{K1:ASC-DC5_{P,Y}}}} are used for the DC centering controls
==== POP ====
 * DC control loop not implemented yet
==== AS ====
 * DC control loop not implemented yet
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  * DSOFT is IY, DHARD is EY 
 * Loops or noise haven't been characterized 		  * {{{K1:ASC-DSOFT_{P,Y}}}} to IY
  * {{{K1:ASC-DHARD_{P,Y}}}} to EY
 * Loops or noise haven't been characterized
 * No offsets were necessary on the sensors
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= 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.

Angular Sensing and Control (Oct, 2022)

Contents

  1. Angular Sensing and Control (Oct, 2022)
    1. WFS ports
      1. REFL (17, 45 MHz)
      2. POP (17, 45 MHz)
      3. AS (17, 28 MHz)
    2. DC QPD ports
      1. TMSX
      2. TMSY
      3. POP Forward
    3. DC PDs
    4. WFS Commissioning
      1. WFS DC centering
        1. General
        2. REFL
        3. POP
        4. AS
      2. Single Y arm
      3. Single X arm
      4. PRMI
      5. PRFPMI
      6. DRFPMI
  2. Next Steps
    1. Infrastructure
    2. Simulation
    3. Integration
  3. Known issues

WFS ports

REFL (17, 45 MHz)

POP (17, 45 MHz)

AS (17, 28 MHz)

DC QPD ports

TMSX

TMSY

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

General

  • If the beam is off, use the picomotor first because the PZT ranges are not large
  • Beam spots on the quadrant diodes must be centered (DC centering)
    • PZTs and picomotors are available

REFL

  • Open the REFL shutter first for REFL WFS

  • K1:ASC-DC5_{P,Y} are used for the DC centering controls

POP

  • DC control loop not implemented yet

AS

  • DC control loop not implemented yet

Single Y arm

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)