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Full-Text Articles in Physics
Experiment And Results On Plasma Etching Of Srf Cavities, J. Upadhyay, Do Im, J. Peshl, S. Popovic, L. Vuskovic, A. -M. Valente-Feliciano, L. Phillips
Experiment And Results On Plasma Etching Of Srf Cavities, J. Upadhyay, Do Im, J. Peshl, S. Popovic, L. Vuskovic, A. -M. Valente-Feliciano, L. Phillips
Physics Faculty Publications
The inner surfaces of SRF cavities are currently chemically treated (etched or electro polished) to achieve the state of the art RF performance. We designed an apparatus and developed a method for plasma etching of the inner surface for SRF cavities. The process parameters (pressure, power, gas concentration, diameter and shape of the inner electrode, temperature and positive dc bias at inner electrode) are optimized for cylindrical geometry. The etch rate non-uniformity has been overcome by simultaneous translation of the gas point-of-entry and the inner electrode during the processing. A single cell SRF cavity has been centrifugally barrel polished, chemically …
Imperfection And Tolerance Analysis Of Hom Couplers For Odu/Slac 400 Mhz Crabbing Cavity, S. U. De Silva, R. G. Olave, H. Park, J. R. Delayen, Z. Li
Imperfection And Tolerance Analysis Of Hom Couplers For Odu/Slac 400 Mhz Crabbing Cavity, S. U. De Silva, R. G. Olave, H. Park, J. R. Delayen, Z. Li
Physics Faculty Publications
In preparation for the LHC High Luminosity upgrade, a 400 MHz crab cavity has been developed jointly at ODU/SLAC, including two higher order mode couplers designed to dampen the wakefields in order to comply with the impedance budget specified for the LHC system. During fabrication, assembly, and processing of the couplers, a number of imperfections may arise that could modify the higher order mode spectrum and the associated impedance for each mode. We present here a detailed study of the imperfections of the horizontal- and vertical- HOM couplers, and the associated allowed tolerances for manufacture, assembly and processing.
Crab Cavity And Cryomodule Development For Hl-Lhc, F. Carra, A. A. Carvalho, K. Artoos, S. Atieh, I. A. Santillana, S. Belomestnykh, A. Boucherie, J. P. Brachet, K. Brodzinski, G. Burt, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Crab Cavity And Cryomodule Development For Hl-Lhc, F. Carra, A. A. Carvalho, K. Artoos, S. Atieh, I. A. Santillana, S. Belomestnykh, A. Boucherie, J. P. Brachet, K. Brodzinski, G. Burt, S. U. De Silva, J. R. Delayen, R. Olave, H. Park
Physics Faculty Publications
The HL-LHC project aims at increasing the LHC luminosity by a factor 10 beyond the design value. The installation of a set of RF Crab Cavities to increase bunch crossing angle is one of the key upgrades of the program. Two concepts, Double Quarter Wave (DQW) and RF Dipole (RFD) have been proposed and are being produced in parallel for test in the SPS beam before the next long shutdown of CERN accelerator’s complex. In the retained concept, two cavities are hosted in one single cryomodule, providing thermal insulation and interfacing with RF coupling, tuning, cryogenics and beam vacuum. This …
Effects Of Plasma Processing On Secondary Electron Yield Of Niobium Samples, M. Basovic, S. Popovic, M. Tomovic, L. Vuskovic, A. Samolov, F. Cuckov
Effects Of Plasma Processing On Secondary Electron Yield Of Niobium Samples, M. Basovic, S. Popovic, M. Tomovic, L. Vuskovic, A. Samolov, F. Cuckov
Physics Faculty Publications
Impurities deposited on the surface of Nb during both the forming and welding of accelerator cavities add to the imperfections of the sheet metal, which then affects the overall performance of the cavities. This leads to a drop in the Q factor and limits the maximum acceleration gradient achievable per unit length of the cavities. The performance can be improved either by adjusting the fabrication and preparation parameters, or by mitigating the effects of fabrication and preparation techniques used. We have developed the experimental setup to determine Secondary Electron Yield (SEY) from the surface of Nb samples. Our aim is …