title: Design and performance of a new induction furnace for heat treatment of superconducting radiofrequency niobium cavities.
abstract: Superconducting radio frequency (SRF) cavities made of high purity niobium (Nb) are the building blocks of many modern particle accelerators. The fabrication process includes several cycles of chemical and heat treatment at low (∼120 °C) and high (∼800 °C) temperatures. In this contribution, we describe the design and performance of an ultra-high-vacuum furnace which uses an induction heating system to heat treat SRF cavities. Cavities are heated by radiation from the Nb susceptor. By using an all-niobium hot zone, contamination of the Nb cavity by foreign elements during heat treatment is minimized and allows avoiding subsequent chemical etching. The furnace was operated up to 1400 °C with a maximum pressure of ∼1 × 10(-5) Torr and the maximum achievable temperature is estimated to be higher than 2000 °C. Initial results on the performance of a single cell 1.5 GHz cavity made of ingot Nb heat treated at 1200 °C using this new induction furnace and without subsequent chemical etching showed a reduction of the RF losses by a factor of ∼2 compared to cavities made of fine-grain Nb which underwent standard chemical and heat treatments.
authors: Jefferson Lab, Newport News, Virginia 23606, USA.
authors: Pashupati
authors: P
authors: Dhakal
authors: Gianluigi
authors: G
authors: Ciovati
authors: Wayne
authors: W
authors: Rigby
authors: John
authors: J
authors: Wallace
authors: Ganapati Rao
authors: GR
authors: Myneni