After the development of SQUID magnetometers at Ford Research lab[citation-wiki] in 1965, I. K. Harvey at National Standards Lab, Sydney, Australia has shown that the SQUID magnetometers can be used to measure precise equalization of current ratios by precise measurement of superconducting screening current. This device, later known as Cryogenic Current Comparator (CCC), was soon developed into a beam current monitor at Physikalisch-Technische Bundesanstalt (PTB), Berlin. Based on the same principle, a Cryogenic Current Comparator was developed at the Beam Diagnostic group, GSI in 1995 in collaboration with Institute of Solid State Physics, Friedrich Schiller University (FSU), Jena.


The project was kicked off by this magazine article the CCC project at GSI was launched, back in 1991.

This joined project was successfully shown to measure ion beam current down to <10 nA with a bandwidth exceeding 10 kHz. The non-intercepting and absolute measurement possibilities with a wide dynamic range using CCC provided interesting applications in beam diagnostics. Intensity measurements independent of beam energy, type and trajectories with absolute calibration provided the possibility of calibration of other standard intensity measurement devices, especially in the low intensity ranges, where standard beam current transformers cannot be used.

After a number of beam measurements with the CCC, this project lead to award winning results: The 1998 Faraday Cup Award