In his instrument, a fluorescent screen or photographic plate detected the parabolic paths of ions deflected by electric and magnetic fields.  
Using Eugene Goldstein's research on anode rays, J.J. Thomson designed an early version of this tool that he named the "parabola spectrograph."  In his instrument, a fluorescent screen or photographic plate detected the parabolic paths of ions deflected by electric and magnetic fields.  Modern versions of this instrument graph the relative number of deflected ions, creating a series of distinct peaks.  For 10 points-identify this versatile scientific tool used to determine relative atomic masses.
Using Eugene Goldstein's research on anode rays, J.J. Thomson designed an early version of this tool that he named the "parabola spectrograph."  
Mass Spectrometer (accept Mass Spectrograph)