Preparations and characterizations for N2 doping/infusion - PowerPoint PPT Presentation

TTC High Q – High G Working Group, 2 nd May 2019 Preparations and characterizations for N2 doping/infusion capabilities at IPNO D. Longuevergne, M. Fouaidy, IPN Orsay

VACUUM FURNACE Built by TAVVacuum Furnaces Spa and commissioned in 2016  Routinely used for hydrogen degassing (650°C, 10h) of SPOKE resonators with Ti jacket  Dimensions : Max diameter : 700 mm. Max Length : 1600 mm  T emperature up to 1300°C (1°C – 10 °C per minutes). Homogeneity : +/- 5°C  Vacuum systems  Vacuum Valve Primary : Dry screw pump + roots  Cryo pump Roots pump Secondary : cryogenic pump  Vacuum : 5 E -7 – 1 E -6 mbar  Vacuum gauge Screw pump N2 injection line RGA N2 injection line N2 injection valve

VACUUM FURNACE

N2 Injection line  Air liquide ALPHAGAZ 2 (>99.9999%)  Stainless steel line (Ethanol rinsed + 150°C baking for > 100h)  Contamination measurement with RGA while injecting at 10 -4 mbar in furnace QUESTION : How does that look compared to other labs ?

N2 Infusion on samples  First infusion test done on Niobium samples (50 um BCP) exposed directly in furnace (not in Niobium box) QUESTION :  Cycle : Any infusion 800°C during 2h under vacuum  Cooling down at 160°C under vacuum done without  160°C during 48h with 2.5 e -2 mbar N2  caps ? Cooling down to 40°C under vacuum  Primary vacuum gauge Secondary vacuum gauge T emperature

SIMS characterization  Compact SIMS from Hidden Analytical available at IPNO (not TOF-SIMS) Argon 5 keV at 300 nA  Oxygen 5 keV at 300 nA   Sample analysis with Oxygen : First nanometer : First minute 

SIMS characterization First minute After 10 minutes

SIMS characterization  Dynamic SIMS : Oxygen beam

SIMS characterization  Dynamic SIMS : Argon beam

SIMS characterization  Dynamic SIMS : Argon beam

CONCLUSION  Injection line has been cleaned as possible  Ethanol rinsing + 150°C vacuum baking  No significant pollution measured with RGA beside water and Oxygen => Will install chemical filters  SIMS analysis of Nb samples show that N2 infused samples are not more polluted than BCP’d samples  Resolution of our SIMS too low to measure N2, C and N profils.  Next steps :  Infusion of an elliptical cavity from CEA Saclay  TOF-SIMS measurements  Installation of a chemical filter to decrease water and oxgygen content