Booster Collimator Review March 17, 2003 Peter Kasper

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Booster Collimator ReviewMarch 17,
2003Peter Kasper
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Goals of the Review

1. Physics Will the system be able to do what we
   want it to?
2. Radiation Have we properly addressed all the
   radiation issues?
3. Thermal stresses Will it melt or pull itself
   apart?
4. Mechanical Is the mechanical design sound?
5. Electrical and controls Is the electronic design
   sound?
6. Installation and maintenance Can we build and
   maintain it?
7. Project Are our cost and schedule estimates
   reasonable?
8. What have we missed?

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Review Agenda

• Overview and Background Info. (Peter Kasper 10
  min)
• Physics and Radiation (Nikolai Mokhov 30 min)
• Thermal Calculations (Alex Chen 10 min)
• Mechanical Design and Installation (Larry
  Bartoszek 30 min)
• Electrical Design and Controls (Al Legan 20 min)
• Cost and Schedule (Larry Bartoszek 20 min)
• Note that we have allowed an hour for
  interactions with the committee so please feel
  free to ask questions.

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What Are We Trying to Achieve?

• The Booster is being asked to accelerate protons
  at much higher rep-rates and with much higher
  intensities than has ever been contemplated in
  the past.
• In order to control activation of Booster
  components so as to ..
• avoid radiation damage to sensitive components
  (e.g. cables and connectors)
• avoid excessive exposures to personnel,
  particularly in high maintenance areas (RF
  stations)
• we need to intercept those protons that are
  doomed to be lost and ensure ...
• they are lost at as low an energy as possible
• they are lost in a location that is well shielded

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Specifications

• The collimators should reduce losses at other
  locations around the ring without significantly
  impacting the overall efficiency.
• They should be able to handle losses from ..
• 20 of the beam at 400 MeV
• plus 1 of the beam at 8 GeV
• assuming 5E12 p/cycle _at_ 10 Hz
• The shielding should such that under these
  conditions ...
• The above ground radiation does not trip the
  Chipmunk detector
• Activation of water in the sumps is within the
  allowed limits for surface discharge
• Activation of the outside surfaces that are
  accessible to personnel is less than 100 mrem/hr

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Mechanical Specifications

• The mechanical/electrical design should be such
  that ..
• the apertures do no occlude any beam when in the
  out position
• they can be remotely translated by 1.5 inches
  both horizontally and vertically
• they can be remotely positioned to an accuracy of
  1mm
• their orientation can be remotely corrected for
  pitch and yaw misalignments of up to /- 10 mr.
• The time required to move them from fully in to
  fully out should be no longer than a few minutes.
• It should be possible to reliably disable the
  motion controls
• All sensitive components should be serviceable
  without major disruptions to the program
• It should be possible to completely remove them
  from the tunnel even after many months of beam.

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The Solution Primary Collimators
Two primary scattering foils Mounted on
horizontal and vertical drives Installed in
sector 5 mini-straights
Foils scatter protons on the edges of the beam
envelope The scattered beam in intercepted by
the downstream secondary collimators
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The Scheme Appears to Work.

• An early study compared losses around the ring
  with the vertical primary collimator in and out
  of the beam and constant efficiency.
• Losses decreased everywhere except near the
  secondary collimator locations

BLMs with collimator out BLMs with
collimator in
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Secondary Collimators Old Design

• Original design consisted of L shaped copper
  scrapers brazed to a copper beam pipe.
• Stands and motors were designed to allow lots of
  room to stack steel shielding

For testing purposes they were initially
installed without shielding. A major design flaw
was realized in January when we were ready to add
the shielding. To access the collimator itself
in the event of a catastrophic failure would
require removing the shielding and exposing a
VERY hot object. The design was abandoned. The
system had been reviewed in October 2002.
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The Solution New Secondary Collimators
Three identical collimators Two in Long 6 One in
Long 7
Shielding is integrated with the
collimator motors, controls, and moving parts
are protected from the radiation
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Summary

• We believe we have a much better design that
  meets the requirements for serviceability.
• The integrated shielding concept has the
  advantages that
• ALL failure prone components are outside the
  shielding
• The shielding is more uniform ( no cracks or gaps
  )
• It requires less steel because it makes maximal
  use of the available space
• There are no air activation issues since there
  are no air pockets in regions of high radiation
• But ... we do not want to repeat our past
  mistakes
• So ... Please tell us what have we missed!