Comparison of impact ionisation plasma with laser ionisation [Elektronische Ressource] / presented by Anna Mocker

DISSERTATIONSUBMITTED TO THECOMBINED FACULTIES FOR THE NATURAL SCIENCES AND FOR MATHEMATICSOF THE RUPERTO-CAROLA UNIVERSITY OF HEIDELBERG, GERMANYFOR THE DEGREE OFDOCTOR OF NATURAL SCIENCESPRESENTED BYDIPL.-PHYS. ANNA MOCKERBORN IN MANNHEIMORAL EXAMINATION: 19. 1. 2011Comparison of impact ionisationplasma with laser ionisationReferees:Prof. Dr. EberhardGrun¨Prof. Dr. MarioTrieloffAbstract:Impact ionisation is the basis for the method yielding the highest sensitivity for detection ofdust particles in space. To cover a sufficiently big energy range for the investigation of dustparticle impacts and the calibration of impact ionisation instruments, we attempted to supplythe dust accelerator at the MPI for Nuclear Physics with laser ionisation. Therefore it is nec-essary to investigate the properties of both processes with respect to their comparability. Forthis, the characteristics of the emerging plasma, such as the velocity distribution of the ions,and the ion appearance in the TOF mass spectra are analysed and compared. The findings ofthis study show that, in general, laser ionisation plasma is not comparable to that generated byhypervelocity particle impacts. However, particular aspects of the the laser ionisation processcan be used as a rough substitute for particle impacts, i.e. optimising and testing electroniccomponents for impact ionisation instruments.