Modular High Capacity Current Lead

A high capacity current lead (10) comprises components that are electrically coupled using indium joints. The current lead includes a heat exchanger having a portion at room temperature (100) and a portion (200) within a vacuum cryostat. The room-temperature portion is temperature controlled against both overheating and over-cooling. The cryogenic portion (200) of the heat exchanger is electrically coupled to a coolant boiling chamber (300) using indium joints. The boiling chamber (300) has a lid and a base that may be electrically coupled using indium joints, or they may be brazed. The boiling chamber (300) is surrounded by a vacuum lid that may be electrically coupled to the base using indium joints, or brazed. The base is electrically coupled to a superconductor module (400) having high-temperature superconductor (HTS) tapes for conveying current to a device, such as a superconducting electromagnet.