A Position Sensitive Beam Monitor for a Dust Accelerator K. Otto (1), A. Mocker (1,2), S. Bugiel (1), Z. Sternovsky (3), Y.-F. Xie (3) and R. Srama (1,2) (1) Max-Planck-Institut für Kernphysik, Heidelberg, Germany (2) Institut für Raumfahrtsysteme, Universität Stuttgart, Germany (3) Laboratory for Atmospheric and Space Physics, University of Colorado at Boulder, USA (katharina.otto@mpi-hd.mpg.de / Fax: +49 6221 516 660) Abstract To ascertain a dust particle’s trajectory in the beam line a new developed position sensitive detector is imple- mented in the beam line of the Heidelberg dust acceler- ator. It has been calibrated recently, so that the detector signals could be mapped to a position. Additionally an idealised simulation calculated the expected signals. The accuracy of the detector for various SNR has been determined and represents the position sensitive detec- tor as a valuable and reliable component of a dust ac- celerator. 1. Introduction Investigating the dynamical and physical properties of cosmic dust can reveal a great deal of information about both the dust and its many sources. Over re- cent years several spacecrafts (e.g. Cassini, Stardust, Galileo) have successfully characterised cosmic dust using a variety of techniques.The accurate and reli- able interpretation of collected spacecraft data requires a comprehensive programme of terrestrial instrument calibration. For this, μm and sub-μm sized dust par- ticles are charged and accelerated by an electrostatic accelerator to speeds in excess of 100 km/s. The position sensitive beam monitor was built to de- termine a particle’s position in the beam line by using the charge induced by the passing dust particle. De- pending on the particle’s position a different amount of charge is induced on conductive plates that can be amplified and analysed [2]. 2. Design The position sensitive beam monitor includes four pairs of copper coated PCB plates of 1007.5mm 2 area facing its opposite with a distance of 15mm. The pairs are perpendicular to its neighbouring pairs so that a dust particle’s displacement from the center can be de- tected in every direction. One plate of each pair is grounded, the other one is connected to a collective Figure 1: Rack of the position sensitive detector. Blue symbolizes PEEK, red copper. The detecting plates are justified perpendicular to the PEEK plates and not shown in this sketch. charge amplifier. The pairs are separated by copper orifices to shield them from each other. Charged dust particles passing this set up induce charge on the PCB plates that is higher the closer the particle passes the measuring plate. Thus, the signal can be recorded by one channel of the oscilloscope, and the position of the particle relative to the plates is derived by the relative heights of the sequent signals. The advantage here is that all four detecting plates are connected to the same charge amplifier, so that no fur- ther calibration of amplifying devices is necessary. Subsequently a signal produced by the position sensi- tive detector shows four charge peaks in which the first and third give information about the horizontal posi- tion of the passing particle and the second and forth peak give information about the vertical position, see figure 2. 3. Simulation A signal produced by the position sensitive detector not only varies depending on the passing dust parti- EPSC Abstracts Vol. 6, EPSC-DPS2011-1052, 2011 EPSC-DPS Joint Meeting 2011 c  Author(s) 2011