Compatibility Study of the LiteBIRD SQUID Controller Unit With a Dual-Stage SQUID Amplification Chain

IEEE Transactions on Applied Superconductivity, vol. 36, pp. 1601406

Abstract

The LiteBIRD satellite will map the polarisation of the Cosmic Microwave Background (CMB) with unprecedented sensitivity by means of antenna-coupled transition edge sensors (TESs). Its current design features single SQUID-Array Amplifiers (SAA) at a temperature of about 400 mK in order to read out up to 64 TESs in a frequency division multiplexing scheme. The front-end part of the electronics (the SQUID Controller Assembly -SCA) was designed to handle this configuration. Nevertheless, alternative configurations of the experiment are being studied that might require a dual-stage SQUID (DSS) amplification chain in order to meet thermal and noise requirements. In light of this possibility, we have successfully investigated the feasibility of controlling two individual SAAs in a DSS Amplifier (DSSA) configuration with two independent channels of the present SCA. The SQUID directly connected to the sensor, commonly referred to as ‘front-end’, behaves as an emitter-follower, or buffer, circuit and it decouples the impedance of the TES(s) from the rest of the readout chain whilst producing a moderate amplification. The second SQUID, ‘booster’, is responsible for a high-gain amplification of the signal and can be thermally decoupled from the front-end allowing it to dissipate a lot more power and thus exhibiting a higher gain. We characterised a breadboard model in which two SQUID amplifiers are cascaded but hosted on the same circuit board and thus not thermally decoupled. This was intended to perform functional tests and to assess the feasibility of controlling a DSSA without introducing major changes in the already developed LiteBIRD SCA. We present the typical I-V and I-$\Phi$curves of the two SQUIDs along with the characterisation of the DSSA in terms of bandwidth, linearity and total harmonic distortion (THD).

Authors 17

1. Mario de Lucia

   University of Pisa

   Affiliation as printed

   Università di Pisa

2. Paolo Dal Bo

   University of Pisa

   Affiliation as printed

   Università di Pisa

3. A. Tartari

   Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

   Affiliation as printed

   INFN Sezione di Pisa

4. Jean-François Cliche
   Affiliation as printed

   Three-Speed Logic Inc

5. Giulia Conenna Aachen Space Research Organization Netherlands (SRON)

   Space Research Organisation Netherlands

   Affiliation as printed

   Space Research Organization Netherlands (SRON)

6. Gabriele Coppi

   University of Milano-Bicocca

   Affiliation as printed

   University of Milano Bicocca

7. E. Di Giorgi

   University of Pisa

   Affiliation as printed

   Università di Pisa

8. Matt Dobbs

   McGill University

   Affiliation as printed

   McGill University

9. Tommaso Lari

   University of Pisa

   Affiliation as printed

   Università di Pisa

10. Maurizio Massa

    Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

    Affiliation as printed

    INFN Sezione di Pisa

11. Andrea Moggi

    Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

    Affiliation as printed

    INFN Sezione di Pisa

12. Joshua Montgomery

    McGill University

    Affiliation as printed

    McGill University

13. Donato Nicolò

    University of Pisa

    Affiliation as printed

    Università di Pisa

14. Michele Pinchera

    Istituto Nazionale di Fisica Nucleare, Sezione di Pisa

    Affiliation as printed

    INFN Sezione di Pisa

15. Graeme M. Smecher

    McGill University

    Affiliation as printed

    McGill University

16. M. Zannoni

    University of Milano-Bicocca

    Affiliation as printed

    University of Milano Bicocca

17. G. Signorelli

    University of Pisa

    Affiliation as printed

    Università di Pisa