A   B   C   D   E   F   G   H   I   J   K   L   M   N   O   P   Q   R   S   T   U   V   W   X   Y   Z    

Krawczyk, F.L.

Paper Title Page
TPPT088 Power Dependence of the RF Surface Resistance of MgB2 Superconductor 4215
  • T. Tajima, A. Findikoglu, A.J. Jason, F.L. Krawczyk, F. M. Mueller, A. H. Shapiro
    LANL, Los Alamos, New Mexico
  • R.L. Geng, H. Padamsee, A.S. Romanenko
    Cornell University, Laboratory for Elementary-Particle Physics, Ithaca, New York
  • B. Moeckly
    STI, Santa Barbara, California
  MgB2 is a superconducting material that has a transition temperature (Tc) of ~40 K. Recently, it has been shown at 4 K, liquid helium temperature, that the surface RF resistance can be lower than Nb that has the Tc of 9.2 K and has been used for most superconducting RF cavities in the past decades. One of the problems with other high-Tc materials such as YBCO was its rapid increase in RF surface resistance with higher surface magnetic fields. Recently, we have shown that MgB2 shows little increase up to about 120 Oe, equivalent of an accelerating field of about 3 MV/m. The highest field tested was limited by available power. This result is encouraging and has made us consider fabricating a cavity coated with MgB2 and test it. Also, there might be a potential that this material has a higher critical magnetic field that enables the cavity to run at a higher gradient than Nb cavities.  
ROAC006 W-Band Source Development at Los Alamos
  • B.E. Carlsten, L.M. Earley, P. Ferguson, F.L. Krawczyk, J. M. Potter, S.J. Russell, Z-F. Wang
    LANL, Los Alamos, New Mexico
  • S. Humphries
    Field Precision, Albuquerque, New Mexico
  Funding: This work was supported by funds from the Laboratory-Directed Research and Development program at Los Alamos National Laboratory, operated by the University of California for the U.S. Department of Energy.

A high-power mm-wave source architecture is being developed at Los Alamos, based on the interaction of a sheet-electron beam with a ridged waveguide slow-wave structure. This type of traveling-wave source is capable of producing peak output rf powers up to 500 kW at 100 GHz. We will describe the source concept, present interaction simulations, and review rf structure design and cold test results and sheet beam propagation experiments.