Monday 16 December 2013
to 11:00 at
Richard Thomas (Molecular Physics Department)
In this talk I will describe the design and construction of a novel type
of ion storage device currently undergoing commissioning here at
Stockholm University. This device uses purely electrostatic focussing
and deflection elements and allows ion beams of opposite charge to be
confined under extreme high vacuum and cryogenic conditions in separate
''rings'' and then merged over a common straight section. The unique
construction of this Double ElectroStatic Ion Ring ExpEriment (DESIREE)
apparatus allows for studies of interactions between cations and anions
at low and well-defined centre-of-mass energies down to 10 meV .
The technical advantages of using purely electrostatic over magnetic
elements are many, but the most relevant are: electrostatic elements are
more compact and easier to construct; remanent fields, hysteresis and
eddy-currents, highly problematic in magnetic devices, are no longer
relevant, and for low energy ion beams (keV vs MeV) electrostatic
elements are more efficient and cheaper to use.
I will present the current results from the commissioning of the DESIREE
facility : the system is under vacuum at cryogenic temperatures, and
early tests show storage of low energy ions up to 20 minutes, and
highlight some of the technical issues that have arisen during its
development and construction .
Finally, the advantages of this design are a boon to fundamental
experimental studies, not only in atomic and molecular physics but also
in the boundaries of these fields with chemistry and biology, and I will
finish by discussing several examples of such potential research.
 R. D.Thomas et al., Rev. Sci. Instrum. 82, 065112 (2011)
 H. T. Schmidt et al., Rev. Sci. Instrum. 84, 055115 (2013)
 S. Rosén et al., Rev. Sci. Instrum. 78, 113301 (2007)