PAC09 - List of Authors (Crawford, A.C.)

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Crawford, A.C.

Paper	Title	Page
WE5PFP055	Improved Performance of JLab 7-Cell Cavities by Electropolishing	2126
	C.E. Reece, A.C. Crawford, R.L. Geng JLAB, Newport News, Virginia
	Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177 The great majority of experience in niobium SRF cavity processing at Jefferson Lab is with BCP etching. This has been used on CEBAF cavities and others totaling over 500 in number. With improved process quality control, field emission is now largely controlled and other factors limit performance. All of the prototype cavities developed for the 12 GeV upgrade, although meeting minimum requirements, have demonstrated a Q-drop in the 17 23 MV/m range that is not remedied by 120 C bake. Most of these cavities received >250 micron removal by BCP etch. Three of these cavities are being electropolished using the protocol under development within ILC R&D activities. The first such cavity was transformed from Q = 3 ·10¹⁰ at 17 MV/m to quench from 10¹0 at 35 MV/m. The details of this and two subsequent electropolished JLab 7-cell cavities will be reported.

Paper

Title

Page

WE5PFP055

Improved Performance of JLab 7-Cell Cavities by Electropolishing

2126

C.E. Reece, A.C. Crawford, R.L. Geng
JLAB, Newport News, Virginia

Funding: Authored by Jefferson Science Associates, LLC under U.S. DOE Contract No. DE-AC05-06OR23177

The great majority of experience in niobium SRF cavity processing at Jefferson Lab is with BCP etching. This has been used on CEBAF cavities and others totaling over 500 in number. With improved process quality control, field emission is now largely controlled and other factors limit performance. All of the prototype cavities developed for the 12 GeV upgrade, although meeting minimum requirements, have demonstrated a Q-drop in the 17 23 MV/m range that is not remedied by 120 C bake. Most of these cavities received >250 micron removal by BCP etch. Three of these cavities are being electropolished using the protocol under development within ILC R&D activities. The first such cavity was transformed from Q = 3 ·10¹⁰ at 17 MV/m to quench from 10¹0 at 35 MV/m. The details of this and two subsequent electropolished JLab 7-cell cavities will be reported.