Journal of Low Temperature Physics

, Volume 167, Issue 5–6, pp 726–731

Cryogenic Integrated Offset Compensation for Time Domain SQUID Multiplexing

  • D. Prêle
  • F. Voisin
  • J. Martino
  • E. Bréelle
  • G. Bordier
  • M. Piat
Article

DOI: 10.1007/s10909-012-0606-7

Cite this article as:
Prêle, D., Voisin, F., Martino, J. et al. J Low Temp Phys (2012) 167: 726. doi:10.1007/s10909-012-0606-7

Abstract

Superconducting QUantum Interference Device (SQUID) multiplexing is a common technique in the use of large arrays of Transition Edge Sensors (TES). A Time Domain Multiplexer (TDM) combines input TES signals into one output signal using several SQUIDs. Different TES, SQUID and amplifier characteristics induce unavoidable different offsets on the multiplexed signal. Additionally, given the periodicity of the SQUID characteristic, the Flux Locked Loop (FLL) operating point is only defined modulo Φ0. This can lead to a large output offset. In multiplexed mode, the difference between offsets associated with different pixels can induce a parasitic signal which is often larger than that of the TES. These offset signals drastically constrain the readout dynamic range and thus the maximum gain allowed. They also limit the signal-to-noise ratio, the FLL stability and the multiplexing frequency.

Offsets in SQUID readout are discussed and offset compensation for TDM is presented. The dynamic calibration and compensation on a simplified 4:1 TDM are demonstrated in simulation. Dynamic offset compensation is being implemented on a cryogenic SiGe integrated circuit operated at 4 K for 128:1 TDM.

Keywords

Offset-compensation Flux locked loop Time domain SQUID multiplexing Cryogenic integrated circuit 

Copyright information

© Springer Science+Business Media, LLC 2012

Authors and Affiliations

  • D. Prêle
    • 1
  • F. Voisin
    • 1
  • J. Martino
    • 1
  • E. Bréelle
    • 1
  • G. Bordier
    • 1
  • M. Piat
    • 1
  1. 1.AstroParticule & Cosmology laboratory (APC)CNRS—Paris Diderot UniversityParisFrance

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