Various phenomena of residual gas ionization, photoemission or synchrotron radiation cause the generation of additional electrons and may have influence on the performance of elementary particle accelerators. This results in a significant loss of accelerated elementary particles beam. In order to make the CERN Super Proton Synchrotron (SPS) able to deliver the sufficient density proton or positron beam to the Large Hadron Collider (LHC) and reach maximum luminosity at the collision points, it is necessary to prevent the formation of e-clouds in the SPS. This phenomenon is also very important in other applications, firstly, in high-power microwave sources  and in radio frequency devices employed in space. The main project goal – to reveal the physical mechanisms related to control of the secondary electron emission in thin coatings and structures, used in vacuum chambers of the particle accelerators. The main tasks to be solved during the project include: 1st task: Investigate the relation of the secondary electron yield with the optical properties of diamond like carbon films; 2nd task: To form DLC thin films on Kapton substrates (DLC on Kapton substrates used in the secondary electron yield and gas detectors) and to investigate physical properties; 3rd task: To investigate to possibility to use different periodic structures for the decrease of secondary electron yield coefficient.
Lithuanian Academy of Sciences
Analysis of the structure of the films (sp3/sp2 variation depending on deposition conditions, evaluated using Raman scattering spectroscopy) will be identified as it is also crucial aspect in explaining the physical mechanism of SEY from the amorphous carbon films. SEY will be determined directly (CERN facilities) and indirectly using XPS technique (KTU) that will allow us to relate this data with the determined optical characteristics. DLC surface will be structured using different laser parameters (fluence, number of pulses, polarization) and different pitches. By changing laser fluence and number of pulses, different thicknesses and filling factors can be achieved. Circular and linear polarization can have an impact on
Period of project implementation: 2019-05-27 - 2019-12-31
Project coordinator: Kaunas University of Technology