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