Scintillating Screen Applications in Accelerator Beam Diagnostics

Scintillation screens are widely used for transverse beam profile diagnostics at particle accelerators. The monitor principle relies on the fact that a charged particle crossing the screen material deposits energy which is converted into detectable light. The resulting photon emission leads to a direct image of the two-dimensional beam distribution and can be measured with standard optical techniques. Simplicity and low cost make this kind of diagnostic very attractive. During the last years, scintillating screen monitors were mainly deployed in hadron and low energy electron machines. Most recent experiences from modern LINAC-based light sources showed that optical transition radiation (OTR) diagnostics commonly used as standard profile measurement system might fail for high energy and high brilliance electron beams. This makes again the usage of scintillating screens very attractive. Studies showed that the response of scintillating materials depends on many parameters such as particle energy, intensity, species and time structure of the beam. Therefore, scintillating materials have to be tailored with respect to the application demands required at large accelerator facilities. Measured properties, as light yield or imaged beam shape, show a strong dependency on the scintillating material and change significantly with screen temperature as observed for high current ion beams at low energies. In addition, the spectral response of inorganic material might change with intense ion irradiation. Many investigations on scintillating screen properties were performed for particle ίuxes much higher than for typical applications in medical imaging or high energy physics.