Impurity Content Optimization to Maximize QFactors of Superconducting Resonators
Abstract
Quality factor of superconducting radiofrequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of trapped flux, depends on the mean free path. A systematic study of a variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different Ndoping) is carried out. A bell shaped trend appears for the range of mean free path studied. Overdoped cavities fall at the maximum of this curve defining the largest values of sensitivity. In addition, we have studied the trend of the BCS surface resistance contribution as a function of mean free path, showing that Ndoped cavities follow close to the theoretical minimum. Adding these results together we show that the 2/6 Ndoping treatment gives the highest Qfactor values at 2 K and 16 MV/m, as long as the magnetic field fully trapped during the cavity cooldown is lower than 10 mG.
 Authors:
 Fermilab
 IIT, Chicago
 IIT, Chicago (main)
 Publication Date:
 Research Org.:
 Fermi National Accelerator Lab. (FNAL), Batavia, IL (United States)
 Sponsoring Org.:
 USDOE Office of Science (SC), High Energy Physics (HEP) (SC25)
 OSTI Identifier:
 1420925
 Report Number(s):
 FERMILABCONF16740TD
1633201
 DOE Contract Number:
 AC0207CH11359
 Resource Type:
 Conference
 Resource Relation:
 Conference: 28th International Linear Accelerator Conference, East Lansing, Michigan, 09/2509/30/2016
 Country of Publication:
 United States
 Language:
 English
 Subject:
 43 PARTICLE ACCELERATORS
Citation Formats
Martinello, Martina, Checchin, Mattia, Grassellino, Anna, Melnychuk, Oleksandr, Posen, Sam, Romanenko, Alexander, Sergatskov, Dmitri, and Zasadzinski, John. Impurity Content Optimization to Maximize QFactors of Superconducting Resonators. United States: N. p., 2017.
Web. doi:10.18429/JACoWLINAC2016TUPLR023.
Martinello, Martina, Checchin, Mattia, Grassellino, Anna, Melnychuk, Oleksandr, Posen, Sam, Romanenko, Alexander, Sergatskov, Dmitri, & Zasadzinski, John. Impurity Content Optimization to Maximize QFactors of Superconducting Resonators. United States. doi:10.18429/JACoWLINAC2016TUPLR023.
Martinello, Martina, Checchin, Mattia, Grassellino, Anna, Melnychuk, Oleksandr, Posen, Sam, Romanenko, Alexander, Sergatskov, Dmitri, and Zasadzinski, John. Mon .
"Impurity Content Optimization to Maximize QFactors of Superconducting Resonators". United States.
doi:10.18429/JACoWLINAC2016TUPLR023. https://www.osti.gov/servlets/purl/1420925.
@article{osti_1420925,
title = {Impurity Content Optimization to Maximize QFactors of Superconducting Resonators},
author = {Martinello, Martina and Checchin, Mattia and Grassellino, Anna and Melnychuk, Oleksandr and Posen, Sam and Romanenko, Alexander and Sergatskov, Dmitri and Zasadzinski, John},
abstractNote = {Quality factor of superconducting radiofrequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of trapped flux, depends on the mean free path. A systematic study of a variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different Ndoping) is carried out. A bell shaped trend appears for the range of mean free path studied. Overdoped cavities fall at the maximum of this curve defining the largest values of sensitivity. In addition, we have studied the trend of the BCS surface resistance contribution as a function of mean free path, showing that Ndoped cavities follow close to the theoretical minimum. Adding these results together we show that the 2/6 Ndoping treatment gives the highest Qfactor values at 2 K and 16 MV/m, as long as the magnetic field fully trapped during the cavity cooldown is lower than 10 mG.},
doi = {10.18429/JACoWLINAC2016TUPLR023},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Mon May 01 00:00:00 EDT 2017},
month = {Mon May 01 00:00:00 EDT 2017}
}

Quality factor of superconducting radiofrequency (SRF) cavities is degraded whenever magnetic flux is trapped in the cavity walls during the cooldown. In this contribution we study how the trapped flux sensitivity, defined as the trapped flux surface resistance normalized for the amount of flux trapped, depends on the mean free path. A variety of 1.3 GHz cavities with different surface treatments (EP, 120 C bake and different Ndoping) were studied in order to cover the largest range of mean free path nowadays achievable, from few to thousands of nanometers. A bell shaped trend appears for the range of mean freemore »

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