15th International Conference on RF Superconductivity, Chicago, United States Review of RF Sample Test Equipment and Results Work supported by the German Doctoral Students program of the Federal Ministry of Education and Research (BMBF) Acknowledgements: Wolfgang Weingarten and everybody from CERN BE/RF and TE/CRG Carsten Welsch (University of Liverpool, Cockcroft Institute, Daresbury) Ernst Haebel (CERN) 1. Illuminating a superconducting Sample by RF 1/11 3 B‫׀׀‬ TE011 mode max • Small samples can be exposed to RF using a pill box cavity with demountable endplate • Three possible techniques • Replacement • Thermometry • Calorimetric 0 Demountable endplate [email protected] Flange Host cavity 1. Illuminating a superconducting Sample by RF 1/11 3 B‫׀׀‬ TE011 mode max • Small samples can be exposed to RF using a pill box cavity with demountable endplate Bruenseraede et al (1971) • Three possible techniques • Replacement • Thermometry • Calorimetric 0 Demountable endplate [email protected] Flange Host cavity 1. Illuminating a superconducting Sample by RF 1/11 3 B‫׀׀‬ TE011 mode max • Small samples can be exposed to RF using a pill box cavity with demountable endplate • Three possible techniques • Replacement • Thermometry • Calorimetric 0 THPO050 [email protected] Demountable endplate Flange Host cavity 2. The Calorimetric Measurement Technique 2/11 Temperature T (Sensor) Bath Temperature PRF (Cavity) PDC,2 PDC (Heater) PRF Temperature of Interest PDC,1 Sample Power time DC on ≈60 s PRF  PDC ,1  PDC , 2  1 2 R Surface H Sample R Surface  2 ( PDC ,1  PDC , 2 )  Sample [email protected] 2 H dS 2 dS RF on ≈40 s 2. The Calorimetric Measurement Technique 2/11 Temperature T (Sensor) Bath Temperature PRF (Cavity) PDC,2 PDC (Heater) PRF Temperature of Interest PDC,1 Sample Power time DC on ≈60 s PRF  PDC ,1  PDC , 2  1 2 R Surface H 2 RF on ≈40 s dS Sample R Surface  2 ( PDC ,1  PDC , 2 )  Sample [email protected] 2 H dS Direct Measurement 2. The Calorimetric Measurement Technique 2/11 Temperature T (Sensor) Bath Temperature PRF (Cavity) PDC,2 PDC (Heater) PRF Temperature of Interest PDC,1 Sample Power time DC on ≈60 s PRF  PDC ,1  PDC , 2  1 2 R Surface H 2 RF on ≈40 s dS Sample R Surface  2 ( PDC ,1  PDC , 2 )  [email protected] 2 H dS Sample Direct Measurement • Measurement of transmitted power Pt • Pt=c∫H2ds, c from computer code 2. TE011/TE012 Cavity from CEA Saclay and IPN Orsay1,2 Feedthrough + Pumps 3/11 DC Heater Temperature Sensors Cavity Sample • TE011 (4 GHz) TE012 (5.6 GHz) • Developed from CEA Saclay/IPN Orsay1 • Modified cavity recently comissioned2 Cavity Sample 1 M. [email protected] 2 Fouaidy, P. Bosland et al. - EPAC 2002, Paris, France G. Martinet et al. – SRF 2009, Berlin, Germany 2. TE011/TE012 Cavity from CEA Saclay and IPN Orsay1 • Systematic sample studies • Correlation with surface properties • Nb film residual surface resistance increases with the substrate roughness 50 μm 4 GHz 4/11 [email protected] 1 M. Fouaidy, P. Bosland et al. - EPAC 2002, Paris, France 3. Sapphire loaded cavity at JLAB3,4 5/11 • Sapphire rod attached inside the cavity lowers resonance frequency • 7.5 GHz for 5 cm sample diameter Sapphire Rod TE011 Cavity 3 L. [email protected] 4 Phillips et al. – SRF 2005, Ithaca, United States B. Xiao et al. – Rev. Sci. Instrum. 82, 056114 (2011) 6/11 ∆λ [nm] RS [μΩ] RS [μΩ] 3. Sapphire loaded cavity at JLAB4 Tc/T T [K] T [K] • Derive material parameters from surface impedance measurements • ∆/kTc=1.842, λ(0 K) =45.3 nm, London penetration depth=36.1 nm, coherence length=51.3 nm, mean free path=256 nm, Rres=1.54 μΩ for Niobium Sample Results on MgB2: THPO048 [email protected] 4 B. Xiao et al. – Rev. Sci. Instrum. 82, 056114 (2011) 4. The Quadrupole Resonator at CERN 7/11 Rods 361 mm B max ‫׀׀‬ 0 Sample, E-beam welded to cylinder 5 [email protected] E. Mahner et al. -Rev. Sci. Instrum., Vol. 74, No. 7, July 2003) Junginger et. al – SRF 2009, Berlin Germany 6T. 4. The Quadrupole Resonator at CERN 8/11 Tc=9.25 K Bulk Niobium Sample RRR=50 BCP (T<15°C) 1200 MHz 800 MHz 400 MHz [email protected] 4. The Quadrupole Resonator at CERN 8/11 Tc=9.25 K RS  1200 MHz 800 MHz 400 MHz f 3 dB BW 1200 MHz 800 MHz 400 MHz [email protected] 4. The Quadrupole Resonator at CERN R[nΩ] Bulk Nb f=400,800, 1200 MHz T=2..10.5 K Tc/T R[nΩ] Nb on Cu f=400, 800, 1200 MHz T=2..10.5 K Tc/T 8/11 4. The Quadrupole Resonator at CERN 8/11 400MHz 100 f=400,800, 1200 MHz T=2..10.5 K T=2, 2.5, 3, 4, 4.5 K f=400 MHz 80 Rs nOhm R[nΩ] R[nΩ] Bulk Nb 60 40 20 Bulk Nb 0 0 10 20 30 40 50 B mT B[mT] Tc/T 800MHz Nb on Cu 1400 Nb on Cu f=400, 800, 1200 MHz T=2..10.5 K Rs nOhm R[nΩ] R[nΩ] R[nΩ] 1200 1000 800 f=800 MHz T=2.1, 2.5, 2.9 3.5, 4 K 600 400 200 0 Tc/T 0 10 20 30 B mT B[mT] 40 50 4. The Quadrupole Resonator at CERN 140 Bulk Nb 120 120 100 100 Bp [mT] Bp[mT] 140 9/11 80 60 40 Nb on Cu 80 60 40 κ(0 K)=1.4 20 κ(0 K)=3.7 20 0 0 6 7 8 T[K] 9 6 7 8 T [K] Solid Curve: Prediction from Vortex Line Nucleation Model Dashed Curve: Prediction from Ginzburg Landau Model [email protected] 9 4. The Quadrupole Resonator at CERN 60 10/11 Bpeak scales with f-0.46+/-0.13 in CW 50 Bp[mT] 40 400 MHz 30 20 1200 MHz 10 Bulk Nb 0 0 0.1 0.2 0.3 1-(T/Tc)2 [email protected] 0.4 0.5 0.6 5. Comparison of the Different Devices 11/11 TE011/012 Cavity Sapphire loaded Quadrupole f [GHz] 4/5.6 7.5 0.4/0.8/1.2 Sample diameter d [cm] 12 5 7.5 Bmax [mT] 40 14 (Amplifier Power) 60 (Quench) Resolution at 5 mT from minimal detectable heating [nΩ] 1.432 1.24 0.44 2 [email protected] 4 G. Martinet et al. – SRF 2009, Berlin, Germany B. Xiao et al. – Rev. Sci. Instrum. 82, 056104 (2011)