Scientific program committee

2005 Journal of the Society for Gynecologic Investigation  
The ion microprobe SNAKE [Superconducting Nanoscope for Applied Nuclear (Kernphysikalische) Experiments] at the Munich 14 MV tandem accelerator provides focused ion beams with spot sizes in the submicrometer range (1). It is used for high-resolution material analysis like hydrogen microscopy or material modification as well as radiobiological experiments. Due to the available ion species and energies, SNAKE is an ideal instrument to use for cell irradiation. The stopping power and thus the
more » ... e can be chosen from about 2 keV/m by irradiating with 25 MeV protons up to several MeV/m for 100 MeV sulfur ions. An upgrade of SNAKE to a single-ion cell irradiation facility was completed 2 years ago and successfully tested and is now routinely used for radiobiological experiments. A narrow ion beam prepared by a micro slit system is focused by the superconducting multipole lens of SNAKE. The beam is transported under vacuum conditions through a flexible coupling to a beam exit nozzle. There the horizontal beam enters the atmosphere by passing a 1-mm bore covered with a 7.5-m Kapton foil. The cell sample to be irradiated is grown onto a thin foil in a specially prepared container positioned in the focal plane of the ion beam. The experiments are done with single, counted ions. These are prepared by a fast switchable electrostatic deflection system and a detector counting ions that have passed through the cell sample (2). In this setup, arbitrary point patterns with an accuracy of 0.55 m in the X direction and 0.40 m in Y direction (both FWHM) can be applied (3) . To observe and align the cells, an inverted microscope was mounted at the beam exit nozzle. By using transmitted light illumination with phase contrast, the cell sample can be visualized without staining techniques that might disturb biological processes. Using the microscope as an inherent position reference, in a first attempt, chosen cell nuclei could be irradiated with an accuracy of about 2 m. The accuracy is mainly limited by the available mechanical positioning system and the low-power objective and might be improved to 1 m. Special microstructured cell carrier foils allow us to easily locate the irradiated cells during retrospective microscopy. Acknowledgments
doi:10.1016/j.jsgi.2005.01.012 fatcat:orxney4yp5gn3hfxid3hfha3iy