ISOLDE Seminar

A Cryogenic Paul Trap for MIRACLS’ 30 keV MR-ToF

by Simon Lechner (CERN, TU Wien)

The MIRACLS project aims to combine the high spectral resolution of conventional fluorescence-based collinear laser spectroscopy (CLS) with high experimental sensitivity. This is achieved by trapping ion bunches in a novel 30 keV MR-ToF (Multi-Reflection Time of Flight) device, in which the ions bounce back and forth between two electrostatic mirrors such that the laser-ion interaction time is increased with each revolution.
The combination of CLS and MR-ToF techniques in MIRACLS constitutes stringent requirements on the emittance of the probed ion bunches. A low energy spread (δE < 1 eV) to minimize the CLS Doppler broadening is as essential as a temporally narrow ion-bunch profile (δt< 500 ns) for MR-ToF operation. Moreover, the transversal emittance should be as small as possible to maintain ion trajectories parallel to the laser-beam axis over thousands of revolutions inside the MR-ToF device.
In order to provide ion bunches which meet the emittance requirements of MIRACLS, a linear Paul trap with cryogenic cooling of the buffer gas down to < 40 K is currently designed. In addition, other experiments (e.g. PUMA, laser spectroscopy of molecules, emission channeling, etc.) would profit as well from such low emittance beams.
This talk will briefly introduce the MIRACLS concept and present the simulation and design status of a compact, cryogenic cooled, linear Paul trap for optimal beam preparation.