Yin Vallgren, C
Calatroni, S
Chiggiato, P
Costa Pinto, P
Neupert, H
Taborelli, M
Rumolo, G
Shaposhnikova, E
Vollenberg, W
Recent Experimental Results on Amorphous Carbon Coatings for Electron Cloud Mitigation
Amorphous carbon (a-C) thin films, produced in different coating configurations by using DC magnetron sputtering, have been investigated in laboratory for low secondary electron yield (SEY) applications. After the coatings had shown a reliable low initial SEY, the a-C thin films have been applied in the CERN Super Proton Synchrotron (SPS) and tested with Large Hadron Collider (LHC) type beams.Currently, we have used a-C thin film coated in so-called liner configuration for the electron cloud monitors. In addition the vacuum chambers of three dipole magnets have been coated and inserted into the machine. After describing the different configurations used for the coatings, results of the tests in the machine and a summary of the analyses after extraction will be presented. Based on comparison between different coating configurations, a new series of coatings has been applied on three further dipole magnet vacuum chambers. They have been installed and will be tested in coming machine development runs.
eng
2011
http://cds.cern.ch/record/1387885/files/CERN-ATS-2011-192.pdf;
Imported from Invenio.
Calatroni, S
Ferreira, L
Macatrao, M
Skala, A
Sosin, M
de Waele, R
Withofs, Y
Status of the EP Simulations and Facilities for the SPL
CERN is assembling a new vertical electropolishing facility in order to process several niobium cavities of beta 1 and beta 0.65 in the context of the HP-SPL R&D programme. Electrochemical simulations are being used in order to define the optimal cathode geometry to process the cavities in a vertical position. Macroscopic properties of fluid dynamics like the Reynolds number and thermodynamics linked to the power dissipated in the process are taken into account to dimension the main system components. All the materials from the different equipments must be compatible with all chemicals within the required working temperature and pressure. To provide safe operating conditions when handling chemicals or processing cavities, specific safety and protection equipment is also foreseen.
eng
2011
http://cds.cern.ch/record/1386713/files/CERN-ATS-2011-191.pdf;
Imported from Invenio.
Baglin, V
Gas Reduction Arising from Particles Interaction in Large Colliders
Workshop on surface phenomena limiting ultimate pressures in vacuum systems.
eng
2011
http://cds.cern.ch/record/1386335/files/CERN-ATS-2011-190.pdf;
Imported from Invenio.
An on-line dynamic magnetic flux analyzer for magnetic measurement is presented. The instrument achieves on-line harmonic analysis by means of an improved implementation of the sliding DFT algorithm on the basis of the Fast Digital Integrator [1]. In particular, the round-off error, unacceptable in digital integrators, is corrected by employing two buffers alternatively. Details about the structure of the instrument and the algorithm implementation are pointed out, and some experimental results are analyzed in order to validate the proposal.
eng
2011
http://cds.cern.ch/record/1385018/files/CERN-ATS-2011-188.pdf;
Imported from Invenio.