Cooley L.

Paper	Title	Page
TU204	Review of SRF Materials Workshop	94
	G. Wu, L. Cooley, H. Edwards Fermilab C. Antoine CEA-Saclay
	The performance of niobium cavities has approached the theoretical hard limit. Yet the consistent achievement of higher performing cavities remains the greatest challenge. To further understand the basic materials science, a workshop was held at Fermilab in May 2007 to present and discuss the fundamental and experimental limitations, and propose new ideas.
	Slides(PDF)
TUP49	ECR Plasma Cleaning: An In-situ Processing Technique for RF Cavities	243
	G. Wu, H. Jiang, T. Khabiboulline, I. Pechenezhskiy, T. Koeth, J. Reid, W. Muranyi, B. Tennis, E. Harms, Y. Terechkine, H. Edwards, D. Mitchell, A. Rowe, C. Boffo, C. Cooper, L. Cooley, R. Schuessler Fermilab W. -D. Moeller DESY Hamburg C. Antoine CEA-Saclay A. Romanenko Cornell University
	A condition for Electron Cyclotron Resonance (ECR) can be established inside a fully assembled RF cavity without the need for removing high-power couplers. As such, plasma generated by this process can be used as a final cleaning step, or as an alternative cleaning step in place of other techniques. We will describe the current effort to study plasma cleaning by ECR in a 3.9GHz cavity.
TUP64	Initial Tests of Atomic Layer Deposition (ald) in Superconducting RF Systems	285
	M. Pellin, J. Elam, J. Moore, J. Norem ANL C. Antoine CEA-Saclay L. Cooley Fermilab T. Prolier, J. Zasadzinski IIT R. Rimmer JLab
	Atomic Layer Deposition (ALD) is a method of synthesizing materials in single atomic layers. We are studying this technique as a method of producing highly controlled surfaces for superconducting RF systems. We have begun tests of ALD coatings of single cells that will involve RF measurements of a cell before and after coating at Argonne. In addition to the tests on complete cells, we are also beginning a program of point contact tunneling measurements to determine the properties of the superconductors at the interface between the bulk niobium and the oxide layer. We describe the method, and tests we are beginning with single cell resonators and small samples.
WEP01	Studies of alternative techniques for niobium cavity fabrication	429
	C. Compton, D. Baars, T. Bieler, J. Bierwagen, S. Bricker, W. Hartung, D. Pendell, R. York Michigan State University L. Cooley, H. Jiang, B. Kephart Fermilab
	Alternative fabrication techniques for superconducting radio frequency (SRF) cavities are being investigated. The main goals are to reduce cavity fabrication costs and expand possibilities for advanced cavity designs. At present, SRF cavities are fabricated via deep drawing of parts from sheet material and electron beam welding (EBW) to join the parts together. EBW produces welds of high quality, but the procedures are costly and timeconsuming. Alternative technologies being explored include tungsten inert gas (TIG) welding of Nb, hydroforming of Nb, and electron-beam free form fabrication (EBFFF) of Nb. If techniques can be developed which do not degrade the Nb purity, TIG welding could reduce or eliminate the need for EBW. Hydroforming could also be an alternative to deep drawing and EBW. As has been demonstrated by several other groups, complete cavities can be hydroformed from Nb tubes in one step using internal pressure and outer dies. Hydroforming of cavities in an industrial setting is presently being explored. EBFFF is a new technique for forming parts from wire stock with an electron beam. Though it may not be suitable for fabrication of a complete cavity, EBFFF could be used to produce tubes for hydroforming or parts for drift tube cavities. Additionally, the possibility of producing single crystal tubes using EBFFF is being explored.