We show that thermal and magnetic contributions to the breakdown of superconductivity in radiofrequency (RF) fields can be separated by applying two RF modes simultaneously to a superconducting surface. We develop a simple model that illustrates how mode-mixing RF data can be related to properties of the superconductor. Within our model the data can be described by a single parameter, which can be derived either from RF or thermometry data. Our RF and thermometry data are in good agreement with the model. We propose to use mode-mixing technique to decouple thermal and magnetic effects on RF breakdown of superconductors.
REFERENCES
1.
R. L.
Geng
, G. V.
Eremeev
, H.
Padamsee
, and V. D.
Shemelin
, “High gradient studies for ILC with single-cell re-entrant shape and elliptical shape cavities made of fine-grain and large-grain niobium
,” in Proceedings of the Particle Accelerator Conference (PAC'2007), June, 2007, pp. 2337
–2339
.2.
F.
Furuta
and K.
Saito
, “50 MV/M recipe for ICHIRO end groups with ethanol rinsing and wiping
,” in Proceedings of the 14th International Conference on RF superconductivity (SRF'2009), August, 2009, pp. 821
–823
.3.
R. A.
French
, “Intrinsic type-II superconductivity in pure niobium
,” Cryogenics
8
(5
), 301
–308
(1968
).4.
F.
Pei-Jen Lin
and A.
Gurevich
, “Effect of impurities on the superheating field of type-II superconductors
,” Phys. Rev. B
85
, 054513
(2012
).5.
M. K.
Transtrum
, G.
Catelani
, and J. P.
Sethna
, “Superheating field of superconductors within Ginzburg-Landau theory
,” Phys. Rev. B
83
, 094505
(2011
).6.
G.
Catelani
and J. P.
Sethna
, “Temperature dependence of the superheating field for superconductors in the high-κ London limit
,” Phys. Rev. B
78
, 224509
(2008
).7.
T.
Yogi
, G. J.
Dick
, and J. E.
Mercereau
, “Critical rf magnetic fields for some type-I and type-II superconductors
,” Phys. Rev. Lett.
39
, 826
–829
(1977
).8.
H.
Padamsee
, D.
Proch
, P.
Kneisel
, and J.
Mioduszewski
, “Field strength limitations in superconducting cavities-multipacting and thermal breakdown
,” IEEE Trans. Magn.
17
(1
), 947
–950
(1981
).9.
G. V.
Eremeev
, “Study of the high field Q-slope using thermometry
,” Ph.D. dissertation (Cornell University
, 2008
).10.
A.
Gurevich
, “Superconducting radio-frequency fundamentals for particle accelerators
,” Rev. Accel. Sci. Technol.
5
, 119
–146
(2012
).11.
V. M.
Uroev
, Equations of Mathematical Physics
, 1st ed. (Yauza
, Moscow
, 1998
) [in Russian].12.
C.
Chou
, D.
White
, and H. L.
Johnston
, “Heat capacity in the normal and superconducting states and critical field of niobium
,” Phys. Rev.
109
, 788
–796
(1958
).13.
A.
Gurevich
, “Multiscale mechanisms of SRF breakdown
,” in Proceedings of the 12th International Workshop on RF Superconductivity
(2005
)A.
Gurevich
, [Physica C
441
(1–2
), 38
–43
(2006
)].14.
T.
Hays
and H.
Padamsee
, “Measuring the rf critical field of Pb, Nb, and Nb3Sn
,” in Proceedings of the 8th Workshop on RF superconductivity (SRF'1997) (1997
), pp. 789
–794
.15.
N.
Valles
and M.
Liepe
, “The superheating field of niobium: Theory and experiment
,” in Proceedings of the 15th International Conference of RF Superconductivity (SRF'2011), July, 2011, pp. 293
–301
.16.
N. W.
Ashcroft
and D. N.
Mermin
, Solid State Physics
, 1st ed. (Thomson Learning
, Toronto
, 1976
).17.
R. L.
Geng
and A. C.
Crawford
, “Standard procedures of ILC high gradient cavity processing and handling at Jefferson Lab
,” in Proceedings of the 15th International Conference on RF superconductivity (SRF'2011), July, 2011, pp. 391
–393
.18.
G.
Ciovati
, T.
Higo
, P.
Kneisel
, J.
Mammosser
, A.
Matheisen
, P.
Michelato
, H.
Padamsee
, D.
Reschke
, T.
Rothgeb
, T.
Saeki
, K.
Saito
, B.
Visentin
, H.
Weise
, and Chr.
Oevermann
, “Final surface preparation for superconducting cavities
,” Technical Report TTC-Report No. 2008-05, DESY
, 2008
.19.
H.
Padamsee
, J.
Knobloch
, and T.
Hays
, RF Superconductivity for Accelerators
(Wiley
, New York
, 2008
).20.
H.
Wang
, “TM010 pass band modes of TESLA 9-cell cavity
,” Technical Report No. JLAB-TN-07-052, TJNAF
, 2007
.21.
Z. A.
Conway
, D. L.
Hartill
, H. S.
Padamsee
, and E. N.
Smith
, “Oscillating superleak transducers for quench detection in superconducting ILC cavities cooled with He-II
,” in Proceedings of the Linear Accelerator Conference (LINAC'2008), September, 2008, pp. 863
–865
.22.
G.
Ciovati
, R.
Flood
, P.
Kneisel
, D.
Machie
, and M.
Morrone
, “A 2-cell temperature mapping system for ILC cavities
,” Technical Report No. JLAB-TN-08-012, TJNAF
, 2008
.23.
G.
Eremeev
, R. L.
Geng
, and A. D.
Palczewski
, “Probing the fundamental limit of niobium in high radiofrequency fields by dual mode excitation in superconducting radiofrequency cavities
,” in Proceedings of the 15th International Conference on RF superconductivity (SRF'2011), July, 2011, pp. 746
–749
.24.
J.
Knobloch
, “Advanced thermometry studies of superconducting RF cavities
,” Ph.D. dissertation (Cornell University, 1997
).25.
P.
Kneisel
, G.
Ciovati
, and A.
Crawford
, “Status of in-house 9-cell fabrication and testing at JLab
,” Technical Report No. JLAB-TN-08-083, TJNAF
, 2008
.26.
J.
Matricon
and D.
Saint-James
, “Superheating fields in superconductors
,” Phys. Lett. A
24
(5
), 241
–242
(1967
).27.
A. D.
Palczewski
, G.
Eremeev
, and R. L.
Geng
, “Design, construction, and initial test of high spatial resolution thermometry arrays for detection of surface temperature profiles on SRF cavities in superfluid helium
,” in Proceedings of the 15th International Conference on RF superconductivity (SRF'2011), July, 2011, pp. 755
–758
.28.
K.
Watanabe
, H.
Hayano
, and Y.
Iwashita
, “Cavity inspection and repair techniques
,” in Proceedings of the 15th International Conference on RF superconductivity (SRF'2011), July, 2011, pp. 598
–602
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