Effects of space charge on the mass purification in Penning traps

The influence of space charge on the mass selection of ions stored in a Penning trap was investigated with the ISOLTRAP experiment at CERN/ISOLDE. A mixture of 85,87Rb +  ions has been used to probe the change of the experimental parameters, e.g. frequencies and amplitudes of the radiofrequency excitations, as a function of the number of ions present in the tra

SIMBUCA, using a graphics card to simulate Coulomb interactions in a Penning trap

In almost all cases, N-body simulations are limited by the computation time available. Coulomb interaction calculations scale with O(N^2) with N the number of particles. Approximationmethods exist already to reduce the computation time to O(N logN), although calculating the interaction still dominates the total simulation time.We present Simbuca, a simulation package for thousands of ionsmoving in a Penning trap whichwill be applied for the WITCH experiment. Simbuca uses the output of the Cunbody-1 library, which calculates the gravitational interaction between entities on a graphics card, and adapts it for Coulomb calculations. Furthermore the program incorporates three realistic buffer gasmodels, the possibility of importing realistic electric andmagnetic fieldmaps and different order integratorswith adaptive step size and error control. The software is released under the GNU General Public License and free for use.status: publishe