Author: Popovic, S.     [Popović, S.]
Paper Title Page
MOPC122 Etching of Niobium Sample Placed on Superconducting Radio Frequency Cavity Surface in Ar/CL2 Plasma 367
 
  • J. Upadhyay, M. Nikolić, S. Popović, L. Vušković
    ODU, Norfolk, Virginia, USA
  • H.L. Phillips, A-M. Valente-Feliciano
    JLAB, Newport News, Virginia, USA
 
  Plas­ma based sur­face mod­i­fi­ca­tion is a promis­ing al­ter­na­tive to wet etch­ing of su­per­con­duct­ing radio fre­quen­cy (SRF) cav­i­ties. It has been proven with flat sam­ples that the bulk Nio­bi­um (Nb) re­moval rate and the sur­face rough­ness after the plas­ma etch­ings are equal to or bet­ter than wet etch­ing pro­cess­es. To op­ti­mize the plas­ma pa­ram­e­ters, we are using a sin­gle cell cav­i­ty with 20 sam­ple hold­ers sym­met­ri­cal­ly dis­tribut­ed over the cell. These hold­ers serve the pur­pose of di­ag­nos­tic ports for the mea­sure­ment of the plas­ma pa­ram­e­ters and for the hold­ing of the Nb sam­ple to be etched. The plas­ma prop­er­ties at RF (100 MHz) and MW (2.45 GHz) fre­quen­cies are being mea­sured with the help of elec­tri­cal and op­ti­cal probes at dif­fer­ent pres­sures and RF power lev­els in­side of this cav­i­ty. The nio­bi­um coupons placed on sev­er­al hold­ers around the cell are being etched si­mul­ta­ne­ous­ly. The etch­ing re­sults will be pre­sent­ed at this con­fer­ence.