Cryogenic Current Comparator for Storage Rings and Accelerators

A Cryogenic Current Comparator (CCC) was developed for a non-destructive, highly sensitive monitoring of nA beams at the planned FAIR accelerator facility at GSI. The sensor part of the CCC was optimized for lowest possible noise-limited current resolution in combination with a high system bandwidth of about 200 kHz. It is foreseen to install the CCC inside the CRYRING, which will act as a well-suited test bench for further optimization of the CCC performance and the cryostat. In the meantime - until the completion of CRYRING - a CCC has been installed and will be tested in the antiproton storage ring (Antiproton Decelerator AD) at CERN. The pulse shape in the AD requires dedicated optimization of the sensor time response. The beam current will increase rapidly during injection from 0 to 12 μA. Since the slew rate of the overall system is limited by the CCC pickup coil, the input signal has to be low-pass filtered to not exceed the slew rate of the CCC system and to ensure a stable operation. For this purpose different low-pass configurations had been tested. In this contribution we present results of the CCC ¬sensor for AD, CRYRING and FAIR, respectively.