The next generation of cryogenic current comparators for beam monitoring

A new Cryogenic Current Comparator with eXtended Dimensions (CCC-XD), compared to earlier versions built for GSI, is currently under development for a non-destructive, highly-sensitive monitoring of nA-intensities of beams for larger beamline diameters planned for the new FAIR accelerator facility at GSI. The CCC consists of a: 1) flux concentrator, 2) superconducting shield against external magnetic field and a 3) superconducting toroidal coil of niobium which is read out by a 4) Superconducting Quantum Interference Device (SQUID). The new flux concentrator (1) comprises a specially designed highly-permeable core made of nano-crystalline material, in order to assure low-noise operation with high system bandwidth of up to 200 kHz. The superconducting shielding of niobium (2) is extended in its geometric dimensions compared to the predecessor CCC and thus will suppress (better -200 dB) disturbing magnetic fields of the beamline environment more effectively. For the CCD-XD readout, new SQUID sensors (4) with sub-μm Josephson junctions are used which enable the lowest possible noiselimited current resolution in combination with a good suppression of external disturbances. The CCC-XD system, together with a new dedicated cryostat, will be ready for testing in the CRYRING at GSI in spring 2017. For the application of a CCC in the antiproton storage ring at CERN a pulse shape correction has been developed and tested in parallel. Results from electrical measurements of two components (1 and 4) of the new CCC-XD setup will be presented in this work.