SPEC(troscopy) -Trap
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Transcript of SPEC(troscopy) -Trap
SPEC(troscopy) -TrapOutline 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
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 @ ωc/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.
Ion Trapping @ 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.
Ion Trapping @ Imperial College
Ca+ ion in a 0.98 Tesla trapping field 3 reds? Old diagram
Ion Trapping @ Imperial College
SPECTRAP/SPECTRAP’
• 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
• 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
Ion Source
Internal Environment
Light Collection
Construction
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
SPECTRAP/SPECTRAP’
Ion Trapping @ Imperial College
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
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 > 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.
SPECTRAP’ RF operation in SIMION
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From Axial Fit C2~0.6
Mathieu stability region
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