1 / 17

Optical Anchor / Interferometer Status: June, 2004

Optical Anchor / Interferometer Status: June, 2004. Josef Frisch. Concept (still just a cartoon). Interferometer. Commercial unit manufactured by Zygo. Single axis purchased, expandable. Heterodyne interferometer Offset frequency set by RF acousto-optical cell

sylvia-edwards
Télécharger la présentation

Optical Anchor / Interferometer Status: June, 2004

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Optical Anchor / Interferometer Status: June, 2004 Josef Frisch

  2. Concept (still just a cartoon)

  3. Interferometer • Commercial unit manufactured by Zygo. • Single axis purchased, expandable. • Heterodyne interferometer • Offset frequency set by RF acousto-optical cell • Good immunity to optical noise • Lambda / 2048 measurement • Low “data age” – allows easy feedback. • Includes: Laser, single axis interferometer, detector, cables, etc.

  4. Interferometer Specs • 0.15nm + 0.5ppb resolution • No detailed noise specs • Expect noise to be better for short timescales • Performance likely limited materials drift • Probably need vacuum transport • Index change of windows with temperature • Thermal expansion of supports • Should be adequate for 1nm stability (relative to ground)

  5. Tasks • Receive Laser (June 2004) • Data acquisition software • Simple test setup to verify basic operation • Test setup for stability / noise • Who guards the guardsmen? • Feedback Software development • Test single axis feedback system • Purchase multi-axis system (6 or 12 axis) • Install system at ATF • Test multi-axis feedback

  6. Data Acquisition • This is probably the most critical issue! • Interferometer in VME format • Plan to integrate with Vibration / ATF VME data-acquisition. • Already have software platform for multi-axis feedback • Requires significant infrastructure for operation • VME crate, VME controller. Unix server. • Software development also requires: • VxWorks development platform

  7. Testing • Plan for Mike Hildrith to test system • Has time and student. • Physical infrastructure for testing probably not too difficult. • What to do about DAQ • Need VME crate + controller (~$12K) • Need host platform / software

  8. System testing software options (1) • Use Vibration / ATF SLAC system • Existing vibration system provides flexible multi-axis characterization and feedback capabilities • Linda Hendrickson guesses “end of summer” to have data acquisition system for interferometer. (will have better estimate when manuals arrive) • Additional manpower may speed this up (but ramp-up time)

  9. System testing software options (2) • Mike Hildrith develops driver compatible with vibration system. • Allows for easy future integration with other data acquisition. • Would need to either purchase VxWorks development environment, or use the SLAC environment remotely.

  10. System testing software options (3) • Develop completely independent platform for testing. • Might be simpler for initial testing. • Would need to re-do work to integrate with existing system, or re-do the very large amount of effort already applied to existing system. • Interferometer hardware required for development, so this would delay driver development at SLAC

  11. Present DAQ system operation • Realtime (vibration) feedback runs at ~1KHz on private bus to DSP • Vibration data (~100KB/sec) from DSP -> crate controller -> ethernet -> NFS • Nanobpm data (~10KB/sec) from crate controller -> ethernet -> EPICS • Scopes independent.

  12. Changes for next generation • Use PPC processor • Feedback calculations in crate controller • Need real time operation of crate controller • Add interferometer support • Looks similar to vibration sensors • Optionally add PC with LabView for scope control. • Use LabView to EPICS interface to centralize data • Optionally replace Solaris NFS server with PC NFS server also running labview

  13. Future direction of software • LabView • Wide variety of hardware supported (in pc format) • Poor support for VME or real time. • EPICS • Wide use in accelerator community • Existing interface to real –time system • Difficult to learn • Make it look like new LCLS system (VME/EPICS)? • Some hardware only in VME • Interferometer (best), 100Ms/s ADC (cheapest) • Good crate density. • Minimal system large and complex • PC bus advantages • Labview, variety of hardware, cheap processing / data storage. • Poorly suited to real-time

  14. Other Tasks • Interferometer support hardware • Probably need vacuum transport lines • Mount corner cubes to support frame / ground (in vacuum?) • Temperature stabilization • 1nm over 1M scale length is ~.0001 degree C. • Support redesign for feedback: • Soft supports, Fast actuators

  15. Goals of Interferometer / optical anchor system • Stabilize a test mass – the NanoBPM support frame • Can measure performance above ~0.1Hz using STS-2 seismometers. • May need multiple seismometers to compare with ground ! • Need to understand beam based experiments. • Can we compare 2 support frames with beam? (may be difficult to get 1nm given lever arm). • 3 independently supported NanoBPMs?

More Related