for Application to RF Cavities for Accelerators

• Published in: IEEE transactions on applied superconductivity Vol. 17; no. 2; pp. 1330 - 1333
• Main Authors: Tajima, T., Canabal, A., Yue Zhao, Romanenko, A., Moeckly, B.H., Nantista, C.D., Tantawi, S., Phillips, L., Iwashita, Y., Campisi, I.E.
• Format: Journal Article
• Language: English
• Published: IEEE 01.06.2007
• Subjects: Co-evaporation; Linear particle accelerator; Magnesium compounds; Materials testing; Niobium; Optical materials; particle accelerators; PLD; Pulsed laser deposition; Radio frequency; superconducting RF cavities; Surface resistance; Tellurium; Temperature; {\hbox{MgB}}_{2}
• ISSN: 1051-8223; 1558-2515
• DOI: 10.1109/TASC.2007.899876

Magnesium diboride (MgB 2 ) has a transition temperature of (T c ) ~40 K, i.e., about 4 times as high as that of niobium (Nb). We have been evaluating MgB 2 as a candidate material for radio-frequency (RF) cavities for future particle accelerators. Studies in the last 3 years have shown that it could have about one order of magnitude less RF surface resistance (R s ) than Nb at 4 K. A power dependence test using a 6 GHz TE 011 mode cavity has shown little power dependence up to ~12 mT (120 Oe), limited by available power, compared to other high- materials such as YBCO. A recent study showed, however, that the power dependence of R s is dependent on the coating method. A film made with on-axis pulsed laser deposition (PLD) has showed rapid increase in compared to the film deposited by reactive evaporation method. This paper shows these results as well as future plans.