SRF2013 - List of Authors (Price, K.M.)

Paper	Title	Page
TUP097	Study of the Temperature Interface Between Niobium and Superfluid Helium. Temperature Waves Measurements from Heat Sources	700
	A. Ganshin, F. Furuta, D.L. Hartill, G.H. Hoffstaetter, K.M. Price, E.N. Smith Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA
	Funding: This work has been supported by NSF award PHY-0969959 and DOE award DOE/SC00008431. One of the most important properties of Superconducting Radio Frequency (SRF) cavities is their ability to disperse generated heat from the internal cavity wall to the external super fluid helium bath. When the generated heat is not removed fast enough, an effect known as thermal feedback dominates, resulting in medium field Q-slope. This medium field Q-slope has the ability to reduce the Q factor should it become strong enough. To determine what physical factors affect the creation of the medium field Q-slope we will be computationally modeling the medium field Q-slope with varying parameters, such as Kapitza conductivity, wall thickness, RF frequency, bath temperature, residual resistivity ratio, residual resistance, and phonon mean path. Our results show that the medium-field Q slope is highly dependent on the Kapitza conductivity and that by doubling the Kapitza conductivity the medium field Q-slope reduces significantly. Understanding and controlling the medium ﬁeld Q-slope will benefit future continuous wave (CW) applications such as the Energy Recovery Linacs (ERL) where cryogenics costs dominate due to CW operation at medium ﬁelds (< 20 MV/m).

Paper

Title

Page

Study of the Temperature Interface Between Niobium and Superfluid Helium. Temperature Waves Measurements from Heat Sources

700

A. Ganshin, F. Furuta, D.L. Hartill, G.H. Hoffstaetter, K.M. Price, E.N. Smith
Cornell University (CLASSE), Cornell Laboratory for Accelerator-Based Sciences and Education, Ithaca, New York, USA

Funding: This work has been supported by NSF award PHY-0969959 and DOE award DOE/SC00008431.
One of the most important properties of Superconducting Radio Frequency (SRF) cavities is their ability to disperse generated heat from the internal cavity wall to the external super fluid helium bath. When the generated heat is not removed fast enough, an effect known as thermal feedback dominates, resulting in medium field Q-slope. This medium field Q-slope has the ability to reduce the Q factor should it become strong enough. To determine what physical factors affect the creation of the medium field Q-slope we will be computationally modeling the medium field Q-slope with varying parameters, such as Kapitza conductivity, wall thickness, RF frequency, bath temperature, residual resistivity ratio, residual resistance, and phonon mean path. Our results show that the medium-field Q slope is highly dependent on the Kapitza conductivity and that by doubling the Kapitza conductivity the medium field Q-slope reduces significantly. Understanding and controlling the medium ﬁeld Q-slope will benefit future continuous wave (CW) applications such as the Energy Recovery Linacs (ERL) where cryogenics costs dominate due to CW operation at medium ﬁelds (< 20 MV/m).