AlMn-Al dual TES bolometer development for CMB telescopes

Transition-edge sensor (TES) as a type of low-temperature superconducting bolometers offers excellent signal-to-noise-ratio, and is one of the most up-to-date technologies used for cosmic microwave background (CMB) observations. The Ali CMB polarization telescope (AliCPT) project in China uses TES bolometers as the focal plane detector through an international collaborative effort. To increase collecting efficiency of the telescope, and include bolometers of different frequency bands, large-scale production of TES bolometer arrays needs to be accomplished in the future. In this work, we developed single pixel TES bolometers, the saturation power and noise equivalent power (NEP) of which satisfy the requirements of 90 GHz and 150 GHz CMB applications. Each of the bolometers consist of a 1200 ppm AlMn alloy TES for CMB science observation and an Al TES for laboratory optical tests. Dark characterization is applied on these bolometers. Their heat capacities are in the range of 0.7\(\sim \)1.6 pJ/K and the NEP values are below 30 aW/\(\sqrt{Hz}\). The T\(_{c}\) values are about 360 mK and can be adjusted to about 410 mK by additional annealing.