X Translation Range

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X Translation Range

• LCLS Undulator Week
• 29 April - 01 May 2008

Contributions to this talk from Geoff Pile, Emil
Trakhtenberg, Marion White
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X Translation Range

• The system, as currently implemented, permits 2
  mm translation WRT beam center, allowing access
  to the 2-mm good-field region of the undulators.
• When all undulators were all to be tuned
  identically, there was a request to have access
  to a 6 mm range.
• All undulators are now individually tuned.
  Wondering why that large a range, most of which
  was thought to be outside the good-field region,
  is still necessary we now understand that the
  good-field region is even better than we had
  hoped.

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Limit-Setting Procedure

• Disconnect motors
• Set Hardstop
• Use 1mm spacer, turn in with screwdriver
• Set LS2 with electronic box
• Set LS1 with electronic box
• Set software limit by finding zero
• Reconnect motors drive via the controls system.

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Stop Switch Positions with 2mm and 5mm
overtravel
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Increasing the Range

• Two steps are necessary to increase the range
  beyond the present
• All horizontal shims must be modified to
  eliminate interference with the vacuum chamber in
  the in position.
• One of the limit switch actuators on each
  translation stage should be replaced with a new
  adjustable one. The design already exists.
• These are reasonably inexpensive machining
  operations, but significant technician and QA
  effort will be required to avoid retuning.

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Each of the approximately 20 horizontal shims
must be clamped down securely, clearly marked,
removed, modified, replaced in the same location,
and for additional certainty, the location should
be verified by a second person.
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Interference to be removed
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Advance carefully
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Watch out for the tuning shims when moving the
Vac Ch