The CERN Antiproton Decelerator AD Status and Future

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The CERN Antiproton Decelerator (AD)Status and
Future

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Introduction

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• Based on a previous CERN machine (the Antiproton
  Collector AC), AD started producing low-energy
  antiproton beams for physics in 2000. Here we
  will discuss problems linked to ADs co-existance
  with CERN main programs and recent decisions
  taken with regard to ADs future.

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Background

• 1980-1986 AA
• 3.57 GeV/c Antiproton Accumulator ring
• 1012 pbars stored (peak). p/pbar collisions in
  SPS
• 1986-1996 AAC (AAAC)
• Large acceptance Antiproton Collector ring added.
  Production rate increased 10-fold to 61010
  pbars/h
• low energy experiments in LEAR
• 1998 - ? AD
• AC converted from fixed energy storage ring to
  Decelerator. 5107 pbars slowed down to 100 MeV/c
  (5.3MeV kinetic). Local experimental area.
• Fast extraction for Penning traps other low
  energy exp.
• ATRAP Production and study of trapped Hbars
• ALPHA Production and study of trapped Hbars
• ASACUSA Spectroscopy on Antiprotonic helium,
  traps etc. etc.
• ACE Biological effect of Pbars gt tumor
  treatment

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AD

• Basic Parameters
• Circumference 182 m
• Production beam 1.51013 protons/cycle
• Injected beam 5107 pbars/cycle
• Beam momenta max-min 3.57 0.1 GeV/c
• Momenta for beam cooling
• Stochastic 3.57 and 2.0 GeV/c
• Electron 0.3 and 0.1 GeV/c
• Transverse emittances h/v 200 1 p.mm.mrad
• Momentum spread 610-2 110-4 dp/p
• Vacuum pressure, average 410-10 Torr
• Cycle length 100 s
• Deceleration efficiency 85

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Operation statistics
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2009 run

• Key dates
• 23/4 Ring closure, start HW-tests
• 11/5 Start setting up with beam
• 8/6 start physics

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AD Consolidation

• Many HW breakdowns of major components since
  2004 several ring/transferline magnets, vacuum
  leaks, power supplies etc.
• Lengthy repairs due to lack of spares, need for
  vacuum bakeout, obsolete equipment, loss of
  know-how etc.
• Reduced AD maintenance/support due to other CERN
  priorities
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• Limited consolidation budget for urgent measures
  granted following approval of AD running 2007 -
  2010
• Consolidation budget requested in 2008 for
  continued AD operation in the medium/long term
• Focus is mainly on consolidating existing
  equipment
• The two scenarios under consideration are
• (1) Continued operation until the end of 2012
  with no major modifications to the AD machine
• (2) Operation until the end of 2016 with the
  possibility to implement the proposed ELENA
  upgrade.

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AD Consolidation

• Analysis of breakdown risks, identification of
  items and costs for consolidation was done as
  well as a risk score classification.
• Some 40 items have been identified, costs
  (manpowermaterial) estimated and summed up for
  the 2 scenarios 2012/2016.
• The matter was discussed at the Research Board
  meeting 5/12/09 It was decided to execute
  approx. 1/3 of the proposed 2016 consolidation
  program. Quote
• Since AD operation will be incompatible with the
  
• new PS2, this sets a clear end-point to the
  programme in 2017. It was agreed that the
• strategy to be followed should have the aim of
  maintaining the AD facility
• operational until then, but consistent with the
  budgetary constraints.

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Proposed new experiment AEGIS

• The proposed AEGIS experiment was in principle
  approved as AD-6 at the RB meeting 5/12/09.
  Budgetary details remain to be worked out.
• Standard fast extraction of the 100 MeV/c beam
• The extension of the existing ACE beamline has
  been foreseen since the beginning of AD and
  requires manufacturing and installation of 2
  quadrupoles, 1 dipole, 3 combined H/V corrector
  magnets and 3 bpms as well as vacuum chambers
  and equipment.
• Work is planned to be started in 2009, first beam
  in 2011

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Long-term AD future

• AD and antiprotons. According to the planning of
  the FAIR project, the antiproton facility in GSI
  should have succeeded to the AD after the year
  2017. The continuation of antiproton experiments
  at CERN after the PS complex is decommissioned is
  therefore unlikely. In spite of this, if an
  antiproton facility is still needed on the CERN
  site, the following scenarios can be envisaged
• For a limited period of time (1-2 years) the old
  PS complex could be kept active and dedicated to
  the production of antiprotons.
• For continuation in the medium term, the AD
  target could receive a proton beam from PS2 via a
  1.3 km transfer line, using a new 650 m long
  tunnel and passing through 3/4 of the PS ring.
• For continuation in the long term, a new and
  modern antiproton facility with its target area
  should be built in a cavern close to PS2.

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Connection to AD for continued Pbar physics in
the medium term.
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In the long term, a new antiproton facility could
be built either 40m underground or in a surface
building further away from PS2
Possible PS2 surface experimental area
Possible PS2 underground experimental areas
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Sideview of baseline scheme
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Long-term AD future

• May 09 meeting to discuss Non-LHC physics
• Objective is to define strategies for optimizing
  physics output at CERN and world-wide
• We might know more about the future of low-energy
  pbar physics after that..

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AD future improvements ELENA
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ELENA basic parameters
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AD future improvements ELENA

• 3,5 years project duration
• 10 MCHF 50 Man-years needed
• CERN approval conditioned to external funding
  50/50
• ELENA was not discussed during RB 5/12/09
• External partners interested in participating in
  the project

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TSR gt ELENA ?

• A visit to the TSR facility at MPI-K Heidelberg
  has enabled us to verify the feasibility of using
  an appreciable amount of the TSR machine
  components for the construction of the proposed
  low energy antiproton ring, ELENA. Even thought
  the TSR ring size (53 m) does not fit the
  dimensions of the ELENA ring, which would have a
  circumference of about 30 m, most of the TSR
  elements could be used for the smaller ring.
• Magnets All 8 bending magnets fit the
  requirements.
• 20 quadrupole magnets are available, 8 are
  required for use in ELENA and the rest will be
  used in the transfer line or kept as spares.
• Orbit correction The 8 backleg windings on the
  main bends will be used for the horizontal orbit
  correction. A total of 12 dipoles are available
  to correct the vertical orbit or to provide extra
  elements for the horizontal correction.
• Injection ejection The magnetic and
  electrostatic septa of TSR could be adapted for
  use in ELENA. The kickers, however, do not fit
  the requirements. In addition an number of
  magnetic correctors can be used in the AD-ELENA
  transfer line.
• Electron cooling It is proposed to use the
  electron target experiment as an electron cooler
  for ELENA. This device comes complete with the
  Faraday cage and high voltage platform. A
  modification to the electron gun will be needed
  in order to exchange the photocathode with a
  conventional thermionic cathode.

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TSR gt ELENA ?

• Vacuum All vacuum chambers are made of 316LN
  stainless steel and are bakeable. Turbo molecular
  pumps, ion pumps and Ti sublimation pumps can all
  be re-used in ELENA. In addition 5 sector valves
  are also available as well as vacuum gauges and
  residual gas analysers. Only the pumps and the
  valves are equipped with bakeout jackets. The
  rest of the machine is equipped with heating
  strips and insulating material. The complete
  control of the bakeout could also be used.
• Instrumentation 8 horizontal/vertical pick-ups
  (LEAR type, fully bakeable) can be used to
  measure the closed orbit. The intensity is
  measured with a standard Bergoz BCT and the
  circulating beam profile is measured with
  ionization profile monitors and a scraper.
  Schottky pick-ups are installed but their use in
  ELENA might be limited due to the low number of
  particles. They would be useful for the tune
  measurement where a dedicated BTF kicker is
  available.
• Taking the above into consideration, we estimate
  that between 2.5 to 3 MCHF could be saved by
  using TSR elements in the construction of the
  ELENA post-decelerator ring. This represents
  about 25 of the total budget.

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TSR gt ELENA ?

• Proposed ELENA/TSR lattice

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