Dark current measurements on a superconducting cavity using a cryogenic current comparator.

Area of Science:

• High-energy physics
• Accelerator science
• Superconductivity

Background:

• Superconducting linear accelerators are crucial for particle physics research.
• Accurate measurement of dark currents is essential for accelerator performance and safety.
• Existing measurement techniques can be limited in noisy environments.

Purpose of the Study:

• To develop and demonstrate a nondestructive method for measuring dark currents in tera electron volt energy superconducting cavities.
• To assess the feasibility of measurements in a highly noisy accelerator environment.

Main Methods:

• Utilized a low-temperature direct current superconducting quantum interference device (dc SQUID) based cryogenic current comparator (CCC).
• Performed measurements in an extremely noisy accelerator environment.
• Achieved high current sensitivity for dark current detection.

Main Results:

• Demonstrated a current sensitivity of 0.2 nA/Hz(1/2) under challenging conditions.
• Successfully enabled the detection of dark currents as low as 5 nA.
• Validated the nondestructive nature of the measurement technique.

Conclusions:

• The developed dc SQUID-based CCC is effective for nondestructive dark current measurements in noisy accelerator settings.
• This method offers a significant advancement for characterizing superconducting linear accelerators.
• The technique has implications for improving the performance and reliability of future accelerators.