NuMI extraction / primary beam requirements are quite severe compared to many previous external primary beam systems

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Introduction NuMI Primary Optics Review 12/11/01

• NuMI extraction / primary beam requirements are
  quite severe compared to many previous external
  primary beam systems
• Very high intensity - 80 of the Main Injector
  output (5/6 batches)
• Severe restrictions on allowable beam loss, with
  the combination of intense beam and primary
  transport tunnel located in the protected
  groundwater aquifer. Need DC equivalent
  fractional beam loss 110-4 , and also rigorous
  prevention of large accidental beam loss.
• For some time, major concerns have existed as to
  whether the beam transport design of record
  provides a viable solution for the required
  intensities and constraints on allowable beam
  loss.

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Concerns re. Primary Beam Transport

• Maximum projected beam sizes vs. aperture are x
  2 larger than for previous high intensity
  transport designs with clean beam transmission.
• MARS modeling (S. Striganov) indicates appearance
  of significant beam loss at several points when
  Gaussian beam tail distributions are considered.
• Potentially severe constraints on achievable
  transport optics imposed by 430 ft. carrier
  tunnel drift without quadrupoles.
• Many concerns expressed by reviewers
• Primary concern that momentum spread used (410-4
  - 95) is unrealistically low for high intensity,
  coupled with very large vertical dispersion in
  design.
• Beam tails must be considered. Design and use
  scrapers if needed.
• Need much more comprehensive characterization of
  MI and extracted beam parameters.

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Aperture PlotBeta - 40p contour dp/p - 1.210-3
- 95
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Approach for DesignImprovement

• Review of beam optics design (P. Lucas) - Look
  toward improvement in maximum beta (was 750
  meters) and maximum eta ( 19) by a factor of
  3 for each parameter. Consider option of
  focusing in the larger tunnel region of the
  carrier tunnel (now also a DOE review
  recommendation).
• Team assembled (led by A. Marchionni) to focus on
  empirical characterization of MI and extracted
  beam parameters.
• Understand requirements for component
  installation in carrier tunnel.
• (R. Ducar)
• Understand impact on other support systems. N.
  Grossman provides initial understanding re. power
  supply system impact.

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Status For This Review

• Efforts are very much work in progress.
• Most valuable review feedback is a technical
  assessment of new optics design to date (work
  initiated late Sept).
• Decision for review at this stage due to the
  fundamental importance of this effort, in
  achieving a solid primary transport design for
  the severe NuMI requirements.

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Presentation Agenda

• Introduction Sam Childress
• Characterization of MI Alberto Marchionni
• beam parameters
• Beam optics design Peter Lucas
• Considerations for component Bob Ducar
• installation in carrier tunnel
• Power supply system impacts Nancy Grossman
• Summary Sam Childress