SPEC(troscopy) -Trap

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SPEC(troscopy) -Trap

• Outline of talk
• Introduction motivation for two cross
  continent traps
• Imperial College Group areas of interest and
  expertise
• SPECTRAP/SPECTRAP a comparison of the
  different requirements
• of the traps
• a L00K at SPECTRAP
• SPECTRAP Experimental plans Layout of the
  Laboratory
• initial trials in RF
  operation
• Penning mode
  configuration
• simulations in SIMION
• Conclusion and Outlook

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Introduction

• It was decided that a clone of SPECTRAP,
  SPECTRAP, would be built in London for the main
  purpose of gaining experience early that can be
  bought to GSI.
• We have a compatible superconducting magnet in
  London. Hence we can be the first to test
  SPECTRAP in a Penning configuration.
• SPECTRAP has a split-ring electrode structure,
  hence a broad usability for other experiments in
  the group e.g. Axialisation fixed freq _at_ ?c/2
• If delays occur at GSI, they will have less of an
  impact on us.
• We can employ real time ion imaging to
  investigate the rotating wall technique Low
  charge states have a much faster optical
  transition.

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Ion Trapping _at_ Imperial College

• Laser cooling and Spectroscopy of single charged
  ions e.g. Ca, Be and Mg. Cooling to
  sub-Kelvin temperatures?
• Applications in Quantum Information Processing
  with electronic energy levels representing the
  qubits.
• We can use existing optical setup for Ca and
  transport laser light through optical fibre to
  the trap.

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Ion Trapping _at_ Imperial College
Ca ion in a 0.98 Tesla trapping field
3 reds? Old diagram
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Ion Trapping _at_ Imperial College
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SPECTRAP/SPECTRAP
Construction

• Gold coated OHFC copper construction.
• Highly charged ions from HITRAP
• with in-flight ion capture.
• Cryogenic
• Pressure 10-13
• LIF capture through wire mesh covered ring
  electrode detection with PMT/APD

• OHFC copper construction
• Singly charged ions created inside the trap
  electron impact ionisation
• Room temperature
• Pressure 10-10
• Solid split ring with through holes for real 2D
  optical imaging on CCD camera

Ion Source
Internal Environment
Light Collection
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SPECTRAP/SPECTRAP

• SPECTRAP optics
• internal collimating lens inside vacuum
  chamber
• spherical mirror doubling
  amount of light collected
• external image relay by high resolution
  fibre optic bundle 10µm
• cores
• CCD camera
• AR coatings throughout.
• SPECTRAP ?

Edmund Optics Image Conduit
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SPECTRAP/SPECTRAP
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Ion Trapping _at_ Imperial College
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Experimental Plans

• 1. RF trap less complex system to start
  debugging a new trap
• optimise internal optics
• 2. Penning trap investigate cloud compression
  using the rotating
• wall technique for
  which we already have the
• electronic driver
  in London
• look for fluorescence from Pb weak
  infrared
• transition at 710 nm to gain experience of
  low LIF
• levels

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SIMION Simulations

• We have models of both traps in SIMION
• SPECTRAP simulation has showed us that we need a
  capture voltage of 6 kV and magnetic field gt 4
  tesla to trap all ions from the Cooler Trap,
  assuming ions delivered at 5 keV/q with emittance
  of 10 mm mrad and diameter of 5mm.
• SPECTRAP RF stability region mapped.

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SPECTRAP RF operation in SIMION
From Axial Fit C20.6
az
Mathieu stability region
qz
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Conclusion

• SPECTRAP is being built in London to trap Ca
  ions with real imaging capabilities
• Early RF operation expected Jan 2008
• Penning operation Feb/Mar 2008