Microprobe
Reproduction of the GSI-Logo, written by the Microprobe
on a cell nucleus Ø ca. 15 µm = 0,015 mm
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The microprobe, view from one side Operation method of the microprobe
The microprobe is used to focus the ion beam from the linear accelerator onto a spot of about one micrometer size. For this purpose, a section of width 10 micrometer is cut out of the ion beam by an object aperture and subsequently demagnified into the plane of the target by a magnetic quadrupole lens triplet. The exact location of the ion-optical image of the object aperture can be defined by a deflecting magnetic dipole field. A low-noise electron detector of high gain makes it possible to individually detect single ions impinging on the target by means of the emitted cloud of secondary electrons. A very fast electrostatic beam switch can be used to stop the arrival of further ions at any desired time.
In some areas of application, microelectronic devices are exposed to ionizing particle radiation that, due to its high energy and range, cannot be shielded. High-flying planes and satellites can be named as examples. Since device failure has catastrophic consequences in these applications, the devices are routinely tested for their so-called radiation hardness prior to their deployment. In addition to the standard measurement of this global parameter, the microprobe enables us to localize sensitive areas within integrated circuits and tolocally quantify their sensitivity. This information may then be used to improve the design of the circuit under test in such a way, that the device becomes more radiation tolerant and thus less fault-prone in its application. Further, these measurements at the microprobe make it possible to gain a deeper scientific understanding of the underlying processes occurring in microelectronic circuitry when ionizing particles pass.
Radiation Biology
Densely ionizing particle radiation results in severe damage in biological systems. While these effects on living organisms can be useful for example in Ion-Beam Radiotherapy, they are at least obstructive for plans of longer-term manned space missions or even catastrophic in cases like Chernobyl. It is of greatest interest to investigate the cellular level the different types of damage themselves, as well as the biological reactions and repair processes triggered by this damage. Using the microprobe, both the applied radiation dose and the place of particle traversal can be precisely defined. In collaboration with the Biophysics Department of GSI, spatial and temporal measurements of different biochemical reactions are performed.