LINX LINear collider IR Xing facility at SLAC Snowmass 2001 July 11 Andrei Seryi, SLAC for NLC colla

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LINXLINear collider IR X-ing facility at
SLACSnowmass 2001July 11 Andrei Seryi, SLAC
for NLC collaboration
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Why do we need IR-FF test facility?

• IR and FF are one of the most critical areas of
  LC
• Prior to start of construction, need to build and
  refine full scale engineering prototypes and
  perform adequate tests

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LINX letter of intent
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LINX engineering test facility
ee- collisions at SLC with 50nm beams
NLC 250 GeV 300/2 360/3.5
same 0.11mm 245/2.7nm 7.5e9

• Beam Energy 30 GeV
• DR emittances g?x,y1100/50E-8m
• FF emittances g?x,y1600/160E-8m
• IP Betas ?x8mm ?y0.1mm
• Bunch length ? z0.1 - 1.0mm
• IP spot sizes ?x,y1500/55nm
• Beam currents N? 6e9

• Test stabilization techniques proposed for future
  linear colliders and demonstrate nanometer
  stability of colliding beams
• Investigate new optical techniques for control of
  beam background
• Provide a facility where ultra-small and
  ultra-short beams can be used for a variety of
  other experiments

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LINX IR and optics
NLC FF
LINX FF
LINX IR
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Nanometer stability of colliding beams
Beam-beam deflection gives 1nm stability
resolution
BPMres
Colliding beams provide a Direct
Model-Independent test of any engineering
solutions to the final doublet stability
problem Not possible at FFTB
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Controlling beam background with nonlinear
elements

• Tail Folding via Octupole Pairs has the promise
  of relaxing collimation depths
• Confidence that comes from an Actual
  Demonstration may permit a great savings in
  collimator design, radiation shielding, and muon
  shielding

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Technical feasibility of LINX
Parasitic to PEP-II Operation 30 HZ, 30
GeV Damping Rings Typical SLC run gex,y
2900/150E-8m-rad Typical FFTB gex,y /
90E-8m-rad gt need x2-3 improvement Best
SLC gex,y / 70E-8m-rad LINX Reduced rep
rate allows long store AND simple rewiring
allows shift of magnetic center of QFs in ring to
act as combined function magnets and to decrease
ex,y by x3 Linac No different than 1994-1997
FFTB runs and recent (E150,E157) FFTB plasma
experiments Arcs 30 GeV running reduces SR
emittance growth to 0 Final Focus Optics are
EASY need only New doublet w/ sextupoles New
octupole pair to investigate tail control
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Ultra-short -low emittance beams

• Producing NLC-like beams increase confidence in
  the program
• Various tests relevant to NLC or exploiting the
  short bunches may be performed
• Plasma wakefield acceleration studies
• Traveling focus study
• Low latency Feed-forward orbit correction
• Collimator tests
• Instrumentation test-bed
• Gamma-gamma collisions

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What else can be done _at_ LINX?

• Tests of fast feedforward
• Tests of traveling focus (allows to play with
  by/sz)

Position of focus is moving during collision
Balakin 91
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LINX staging

• Step 1 Successfully transport e and e- beams
  to the north and south beam dumps respectively.
• Step 2 Demonstrate that the SLC beamlines can
  still deliver high quality colliding beams.
• DECISION POINT TO PROCEED CONSTRUCT DOUBLET
• Step 3 Produce ultra-short beams.
• Step 4 Evaluate the effectiveness of background
  suppression with the new Final Focus optics.
• Step 5 Produce ultra-low emittance beams.
• Step 6 Develop fast intra-pulse feedback
  hardware
• INSTALL NEW DOUBLET
• Step 7 Produce lt 100 nm vertical beam size at
  the IP.
• Step 8 Demonstrate nanometer stabilization at
  the IP.

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LINX timeline
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Summary

• LINX engineering test facility is been considered
  to be created at SLAC on the base of existing
  hardware
• it will help to
• Test stabilization techniques proposed for future
  linear colliders and demonstrate nanometer
  stability of colliding beams
• Investigate new optical techniques for control of
  beam background
• Provide a facility where ultra-small and
  ultra-short beams can be used for a variety of
  other experiments
• We are in the process of restoration the SLC arcs
  vacuum and hardware, and evaluating technical
  feasibility of the proposal

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Summary
Effective design of an Interaction Region of a
linear collider is a challenge, but the IR is
also special because its problems are common in
any incarnation of linear collider and the
solutions that may be found will be applicable to
any design, regardless of the choice of RF
technology. The NLC collaboration is addressing
the Worldwide Linear Collider community to
consider participation in the LINX test facility.
We believe that this test facility is of
significant scientific importance and that such
participation will be for our mutual benefit.
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Summary
Preliminary discussion shows positive reaction
from our colleagues from CERN, DESY and
KEK Lets submit the LINX letter of intent
jointly ! Lets joint our efforts and build it !
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Acknowledgement
Special thanks to Leif Eriksson, Lew Keller,
Rainer Pitthan and many other people who are
working on evaluation of technical feasibility of
LINX The tail folding development by octupoles
were inspired by earlier enthusiastic work of
Reinhard Brinkmann, Dick Helm, Rainer Pitthan,
Frank Zimmermann and other people F. Zimmermann,
Octupoles in Front of the Final Doublet, NLC
Accelerator Physics Note, July 14, 1998. R.
Pitthan, Using Octupoles for Background Control
in Linear Colliders - an Exploratory Conceptual
Study, SLAC-PUB-8402, 1999. R.Brinkmann, An
Effective Acceptance Expander for the FFS,
presented at Beam Delivery and Interaction Region
Workshop, July 2000, Thanks to all who
expressed interest and support the LINX proposal