SPEC(troscopy) -Trap

1. 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

2. 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.

3. 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.

4. Ion Trapping @ Imperial College Ca+ ion in a 0.98 Tesla trapping field 3 reds? Old diagram

5. Ion Trapping @ Imperial College

6. SPECTRAP/SPECTRAP’ Construction • 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

7. 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

8. SPECTRAP/SPECTRAP’

10. Ion Trapping @ Imperial College

11. 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

12. 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.

13. SPECTRAP’ RF operation in SIMION From Axial Fit C2~0.6 az Mathieu stability region qz

14. 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