Final Focus optics for Possible New BLine

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Final Focus optics for Possible New B-Line

• A. Seryi, P. Emma, R. Erickson, T. Fieguth, M.
  Hogan, et al.
• 4 October 2004
• NLC BDS meeting

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(No Transcript)
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Shielding wall
Shielding wall
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Notes on Possible New B-Line
Slide from
P. Emma, R. Erickson, T. Fieguth, M. Hogan, A.
Seryi, et al. Sep. 29, 2004
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Notes on Possible New B-Line
Slide from
P. Emma, R. Erickson, T. Fieguth, M. Hogan, A.
Seryi, et al. Sep. 29, 2004
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Longitudinal tracking through B-line, but prior
to FF-system (SPPS mode at 28.5 GeV)
R56 -2.3 mm T566 -35 mm
Notes on Possible New B-Line
Slide from
P. Emma, R. Erickson, T. Fieguth, M. Hogan, A.
Seryi, et al. Sep. 29, 2004
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Possible New B-line Parameters (SPPS-B)
Notes on Possible New B-Line
Slide from
P. Emma, R. Erickson, T. Fieguth, M. Hogan, A.
Seryi, et al. Sep. 29, 2004
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NLC Beam Delivery System
NLC
Final focus with local chromaticity correction
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New B-Line Final Focus

• Same design concept as NLC FF (also adopted for
  ILC FF)
• Local chromaticity correction in FD
• Shorter L, to be compact, but same chromaticity
  as in ILC
• B-Line FF L1m, bY0.1mm
• ILC FF L4m, bY0.4mm
• Additional constraints to be compatible with
  short bunch operation
• Limit R56 and T566 terms
• The tentative optics shown below is designed with
  these constraints
• The optics is tentative (ver.10), and is being
  improved

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New B-Line with sub picosecond bunch compression
New Final Focus
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New FF for B-Line, version SHRTFF10.mad L1m,
and IP bx4mm, by0.1mm (same chromaticity as
present ILC parameters)
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Final Doublet of New FF for B-Line, with
sextupoles for local chromaticity correction,
optics version SHRTFF10.mad
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Survey of New B-Line with FF Optics till FF is in
blue, FF optics is in red z0 at the end of BLINE0
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Survey of New B-Line with FF FF shown in red,
dashed line show straight line from FF entrance
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with B-Line
Evolution of FF optics performance versus version
number Beam size shown is obtained with Turtle
tracking Versions 8,9,10 include New B-Line
bunch compression system
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Performance of B-LineFF optics version 10 Beam
size shown is obtained with Turtle tracking
Already rather good for LCLS beam, can be
further improved for SPPS beam
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New B-Line FF short bunch performance

• Complete system (B-Line FF ver.10)
• R56 -2.29 mm, T566 -77.18 mm
• For beamline up to beginning of FF
• R56 -2.185 mm, T566 -31.29 mm
• gt FF does not change R56 but doubles T566
• gt With SPPS beam (sE1.5), bunch length at IP
  will be lengthened by about 17mm which is still
  smaller than the SPPS beam goal of sz 50mm

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New B-Line FF tracking cross-checks and
Synchrotron Radiation

• Tracking of the full system (B-Line FF ver.10)
  with Turtle and with Dimad agree to better than
  5 in terms of the IP beam size
• Effects of SR (tracking by Dimad) on IP size
  increase
• LCLS beam Dsx2.8 , Dsy0.8
• SPPS beam Dsx6 , Dsy14
• gt SR effects are reasonably small

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B-line FF Parameters and Performance
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Tracked beam at IP of FF for SPPS and LCLS beam
parameters on the same scale
IP beam size of the tracked (SR included) beam in
a complete B-Line FF system LCLS parameters
sx / y 0.44 / 0.070 mm SPPS parameters sx / y
4.5 / 0.160 mm Further optimization of FF
optics may allow further reduction of the IP beam
size in SPPS case
LCLS beam, zoom in
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Changes needed in FF optics ver.10

• Provide space (3m?) for undulators in the
  beginning of FF
• will lead to some lengthening of the system
• Take into account present shield wall
• Will shift FF about 7m downstream, if the wall is
  kept
• Can the shield wall be removed or relocated?
• Lengthen Final Doublet quads QF1 and QD0 about
  twice (for 30 GeV beam)
• will lead to minor lengthening of overall
  beamline
• Determine length needed for beam dump, if there
  is space left, use it for FF or undulators
• Continue optimization, possibly, further reduce
  aberrations for SPPS beam
• Standardize magnets, possibly use existing
• Adjust angles in B-Line to fit to tunnel
  optimally
• Look for ways to reduce T566

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Survey of New B-Line with FF z0 at the end of
BLINE0
If the shield wall remains, need to lengthen
beginning of FF (will also help to create space
for undulators)
Note that the top plot is versus z and bottom
versus s which are 1-1.5m different gt location
correspondence is approximate
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Summary

• New B-Line with sub-picosecond bunch compressor
  and with compact final focus may have the
  following capabilities in terms of the IP beam
  size
• sx,y,z 4.5 0.16 50 mm for 30 GeV SPPS
  beam
• sx,y,z 0.45 0.07 20 mm for 14 GeV LCLS beam