GAN Tools Workshop

1
US LHC ACCELERATOR RESEARCH PROGRAM (US LARP)

brookhaven - fermilab - berkeley

• GAN Scenario for the US LHC Accelerator
• Research Program
• W.C. Turner
• Center for Beam Physics
• LBNL
• Presented at the
• GAN Tools Workshop
• LBNL
• 26 Aug 2002

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Brief history

• BNL, FNAL and LBNL are collaborating on the US
  LHC Accelerator Project
• Started in 1997
• Provides accelerator hardware to CERN IR
  quadrupoles, beam separation dipoles, IR
  absorbers etc
• Ends in 2005 with delivery of equipment to CERN,
  prior to LHC commissioning and operation which
  begins in 2007
• A new collaboration began in 2002 the US LHC
  Accelerator Research Program (US LARP) with the
  purpose of
• Allowing the US to assist CERN with commissioning
  and operation of equipment supplied by the US
• Providing an avenue for US accelerator
  specialists to participate in the frontier energy
  machine and develop their skills
• Training the next generation of accelerator
  specialists
• Helping position the US to be the site of a
  possible future hadron collider

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Components of US LARP

• Commissioning
• Accelerator physics
• Beam instrumentation
• New IR quads (NbSn3)
• All three labs have activities in each of the
  four components.

4
GAN and LHC

• For many reasons it seems unlikely that the full
  blown GAN will be implemented for the LHC
  Accelerator (ATLAS and CMS detectors possibly a
  different story)
• Construction of LHC is well along, GAN not
  included or actively being worked on at CERN
• Pre existing chain of injection accelerators
  dating back to 1950s
• No motion within European member countries to
  host LHC GAN control rooms
• Limited scope and resources of US LARP
• However two areas where GAN tools could be
  usefully employed on LHC are
• Accelerator physics (participation in Machine
  Development studies)
• Instrumentation (remote data logging and
  operation)

5
Culture

• Sociological issues are perceived as a main
  roadblock to employment of GAN
• Using GAN tools for MD studies and logging and
  operation of a limited set of beam instruments
  supplied by the US could help gain acceptance in
  the community for the full blown GAN
• MD studies carried out jointly between
  participating institutions would help foster a
  team culture
• Significant on site presence of participants is
  necessary to develop a team culture
• Envision participants spending six months to a
  year on site during initial commissioning and
  frequent periodic visits afterward
• The host and remote institutions must perceive a
  mutual benefit to using GAN tools
• In the long run the use of GAN tools allows the
  possibility of broader and more frequent
  participation with less expense how this works
  out in practice would be a critical litmus test
  of the concept

6
Controls

• Beam control and operation functions are imagined
  to be carried out by an on site team not by a
  remote team(s)
• Alleviates most of the critical security concerns
• Avoids one of the major sociological hurdles
• Controls of some beam instrumentation parameters
  not effecting beam operation is desirable
• Eg. Running test and debug operations to analyze
  problems or verify equipment is working
• Useful if the expert(s) are at a remote site

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Machine development (MD) studies

• Dedicated runs undertaken to improve machine
  performance, ie luminosity (event rate)
• In LEP 1wk/mo was dedicated to MD studies, in
  LHC ?
• Examples
• Improvement of algorithms for bringing beams into
  collision
• Improvement of injection efficiency
• Investigation of tune space
• etc
• Envision running simulation codes and comparing
  with experimental results
• Electron cloud
• Beam-beam
• ???
• Need flexibility in recording the suite of
  instrumentation needed for particular MD study

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Two examples of instrumentation functions

• Luminosity monitor
• Bring beams into collision
• Maintain beams at optimum luminosity
• Log the luminosity, the luminosity lifetime and
  the beam-beam separation of the 2835 colliding
  bunch pairs (40MHz)
• Monitor crossing angle
• Longitudinal density
• Monitor abort gap density
• Measure longitudinal bunch profiles core, tail
• Monitor ghost bunch density
• Measure untrapped beam fraction prior to ramp
• Injection timing, longitudinal multi bunch
  instabilities
• Envision using the GAN tools for
• Remotely logging and analyzing data during
  routine beam operation
• Exploiting these instruments for MD studies
• Running test procedures to verify operation

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What tools are needed

• Remote replication of the control room
  environment
• Duplication of on site Video monitor displays of
  machine operation
• Video monitors dedicated to viewing the
  participants on both ends
• High quality audio
• Meeting room for development and discussion of
  run plans, analysis, information exchange at
  shift changes etc
• Electronic logbooks
• White boards
• Computers for logging data streams, analyzing and
  displaying summary data, running simulations

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Summary

• The US LARP offers the possibility for a limited
  utilization of GAN tools for Machine Development
  studies and beam instrumentation functions that
  could simultaneously
• Help gain acceptance for a more pervasive use of
  these tools in future accelerators eg NLC
• Increase the participation and cost effectiveness
  of US physicists in LHC operations
• Benefit CERN
• The opinions expressed in this presentation are
  those of the author and not necessarily of
  everyone in the US LARP collaboration