Image charge detection of ion bunches using a segmented, cryogenic detector

Abstract

The response of a dedicated image charge detector to a single passage of small ion bunches was studied. This detector was designed and built in our labs aiming for a maximized signal-to-noise ratio (SNR) with the motivation to enable single ion detection for deterministic ion implantation, a key technique for solid state based quantum technologies, in the future. It is shown how segmentation of the detector with the appropriate combination of the individual segment signal channels significantly increases the SNR. Additionally, the detector is cryogenically cooled to temperatures down to 163 K, further enhancing the SNR. The detection sensitivity of this detector prototype was measured to be 80 elementary charges for SNR=2, detecting 4 keV Xe+ ion bunches. At this SNR, the false-positive error rate is expected to be 0.1%. Comparing the measured sensitivity with a theoretical estimation yielding 22 elementary charges for SNR=2, the presented results lead the way to further optimizations of the detector components and the signal analysis techniques, necessary to realize single ion detection.