We report on low-noise DC SQUID series arrays incorporating intracoil damping, which show smooth DC characteristics. The voltage-flux characteristics of these devices are reproducible upon repeated cooling and do not require multiple heating/cooling cycles to maximize peak-to-peak output voltage modulation depth. The devices consist of 100 DC SQUIDs with individual signal and feedback coils connected in series. The total input inductance is 600 nH, and the peak-to-peak output modulation is 4 mV with a transfer function of 350 V/A. The bandwidth is 5 MHz and the equivalent input current noise is approximately 2.5 pA/root Hz. With these characteristics, these devices are useful as preamplifiers for microcalorimeter X-ray detectors.
Citation: Applied Superconductivity
Pub Type: Journals
microcalorimeter X-ray detectors, arrays, low-noise dc SQUIDs