Quantitative Scintillation Screen Studies at GSI-LINAC and Related Model Calculations

Scintillating screens are commonly used at accelerator facilities, however their imaging quality are not well understood, especially for high current ion beam operation. Several types of inorganic scintillators were investigated for various ion species and energies between 4.8 and 11.4 MeV/u. To validate the imaging quality of the scintillators a scraper scan method was established. For Al2O3 with a Ca beam of 4.8 and 11.4 MeV/u and a constant beam flux (ions/cm²/s), these methods are compared. For 4.8 MeV/u the results are in good agreement, while for 11.4 MeV/u the screen image does not reflect the beam distribution. A microscopic model is under development taking the properties of the fast electrons generated by the primary interaction into account. For Al2O3 this model can describe the observed saturation effect. Spectroscopic investigations were performed, to determine the influence of the ion beam intensity on the luminescence spectra emitted by the materials. No significant dependence on the spectrum with respect to the beam intensity was found for most of the scintillators