Journal Article

On-Sky Performance of the SPT-3G Frequency-Domain Multiplexed Readout

Jones, A., Gilbert, A., Smecher, G., de Haan, T., Michalik, D., Ding, J., Korman, M., Natoli, T., Ferguson, K. R., Benson, B. A., Anderson, A. J., Tucker, C., Lee, A. T., Kofman, A. M., Avva, J. S., Pan, Z., Whitehorn, N., Chang, C. L., Dobbs, M. A., Harke-Hosemann, A. H., Nguyen, H., Yoon, K. W., Paschos, P., Meyer, S. S., Rahlin, A., Bryant, L., Kuhlmann, S., Lowitz, A. E., Dutcher, D., Carter, F. W., Groh, J. C., Story, K. T., Kubik, D. L., Barry, P. S., Kuo, C. -L., Noble, G. I., Cukierman, A., Quan, W., Byrum, K., Thompson, K. L., Carlstrom, J. E., Nadolski, A., Halverson, N. W., Guns, S., Montgomery, J., Riebel, D., Stark, A. A., Stephen, J., Gardner, R. W., Suzuki, A., Howe, D., Everett, W., Ade, P. A. R., Guyser, R., Posada, C. M., Denison, E. V., Gallicchio, J., Young, M. R., Vanderlinde, K., Cecil, T. W., Foster, A., Jonas, M., Vieira, J. D., Basu Thakur, R., Hilton, G. C., Henning, J. W., Jeong, O. B., Wang, G., Leitch, E. M., Vale, L. R., Yefremenko, V., Sobrin, J. A., Khaire, T. S., Novosad, V., Padin, S., Bender, A. N., Shirokoff, E., Sayre, J. T., Cliche, J. F., Harrington, N. L., Holzapfel, W. L., Irwin, K. D., Ruhl, J. E., Pearson,

2019

Overview

Frequency-domain multiplexing (fMux) is an established technique for the readout of large arrays of transition-edge sensor (TES) bolometers. Each TES in a multiplexing module has a unique AC voltage bias that is selected by a resonant filter. This scheme provides for the operation and readout of multiple bolometers on a single pair of wires, reducing thermal loading onto sub-Kelvin stages. The current receiver on the South Pole Telescope, SPT-3G, uses a 68x fMux system to operate its large-format camera of ~16,000 TES bolometers. We present here the successful implementation and performance of the SPT-3G readout as measured on-sky. Characterization of the noise reveals a median pair-differenced 1/f knee frequency of 33 mHz, indicating that low-frequency noise in the readout will not limit SPT-3G’s measurements of sky power on large angular scales. Measurements further show that the median readout white noise level in each of the SPT-3G observing bands is below the expectation for photon noise, demonstrating that SPT-3G is operating in the photon-noise-dominated regime.

• Publisher: Springer
• Subject: Cosmic microwave background / Frequency-domain multiplexing / Transition-edge sensor