Speaker
Victoria Cooley
(University of Wisconsin-Madison)
Description
The goals of Fermilab’s Superconductivity and Radio Frequency Development Department are to engineer, fabricate, and improve superconducting radio frequency (SCRF) cavities in the interest of advancing
accelerator technology. Improvement includes exploring possible limitations on cavity performance and mitigating such impediments. This report focuses on investigating and measuring the Seebeck Effect observed in cavity constituents titanium, niobium, and stainless steel arranged in thermocouples. These junctions exist between cavities, helium jackets, and bellows, and their connection can produce a loop of electrical current and magnetic flux spontaneously during cooling. Such currents could induce trapped flux in cavity surfaces, and lead to loss of quality factor after cool down. Our findings show that welded junctions behave differently than intrinsic junctions, perhaps due to inter-diffusion of elements. An estimate of thermally-induced current is made from the observed voltages and resistivity of the components.
Author
Victoria Cooley
(University of Wisconsin-Madison)
Co-authors
Mr
A. Curtis Crawford
(Fermilab)
Lance Cooley
(Fermilab)
