NJIT-Rutgers Physics Depts Joint Seminar


September 27th, Wednesday (*SPECIAL DAY*)


Light Emission from Particle Beam Excited Gases


Prof. Dr. Andreas Ulrich

Dept. of Physics, Technical Univ., Munich, Germany

(Experimental Astro-Particle Physics, Host: Murnick)


*SPECIAL TIME: 2:45pm-3:45pm with 2:30pm tea time



Electron beam and ion beam excitation of dense gases leads to light emission without the complications associated with gas discharges such as the transition from a glow- into an arc discharge. Observing the beam induced emission with an Echelle spectrograph with 1pm wavelength resolution allows pressure broadening to be observed for a fixed gas temperature over a wide density range with a high quality of the data. The results can be used as an alternative to measuring collisional rate constants via time resolved spectroscopy.


In a project to study the fundamental processes for optical beam diagnostics, the light emission from particle beam excited gases is studied space-and wavelength resolved. Applications are planned for the intense beams projected for the FAIR accelerator facility being built in Darmstadt, Germany. Different gases are tested by recording beam induced spectra to find optical transitions which can clearly indicate the beam position and shape. Recoil processes of both electrons and excited target atoms or ions can blur the actual shape of the beam. Besides observing the beam through appropriate optical filters, it is planned to study the recoil velocities by applying the spectroscopy with pm resolution. An attempt will be made to disentangle recoils effects from pressure broadening.