Characterizing the Sensitivity of 40 GHz TES Bolometers for BICEP Array

Journal Article · Mon Feb 24 00:00:00 EST 2020 · Journal of Low Temperature Physics

DOI:https://doi.org/10.1007/s10909-020-02411-8· OSTI ID:1608641

Zhang, C. ; Ade, P. A. R.; Ahmed, Z.; Amiri, M.; Barkats, D.; Thakur, R. Basu; Bischoff, C. A.; Bock, J. J.; Boenish, H.; Bullock, E.; Buza, V.; Cheshire, J.; Connors, J.; Cornelison, J.; Crumrine, M.; Cukierman, A.; Dierickx, M.; Duband, L.; Fatigoni, S.; Filippini, J. P. ; Hall, G.; Halpern, M.; Harrison, S.; Henderson, S.; Hildebrandt, S. R.; Hilton, G. C.; Hui, H.; Irwin, K. D.; Kang, J.; Karkare, K. S.; Karpel, E.; Kefeli, S.; Kovac, J. M.; Kuo, C. L.; Lau, K.; Megerian, K. G.; Moncelsi, L.; Namikawa, T.; Nguyen, H. T.; O’Brient, R.; Palladino, S.; Precup, N.; Prouvé, T.; Pryke, C.; Racine, B.; Reintsema, C. D.; Richter, S.; Schillaci, A.; Schmitt, B.; Schwarz, R.; Sheehy, C. D.; Soliman, A.; Germaine, T. St.; Steinbach, B.; Sudiwala, R. V.; Thompson, K. L.; Tucker, C.; Turner, A. D.; Umiltà, C.; Vieregg, A. G.; Wandui, A.; Weber, A. C.; Wiebe, D. V.; Willmert, J.; Wu, W. L. K.; Yang, E.; Yoon, K. W.; Young, E.; Yu, C.

The BICEP/Keck (BK) experiment aims to detect the imprint of primordial gravitational waves in the cosmic microwave background polarization, which would be direct evidence of the inflation theory. While the tensor-to-scalar ratio has been constrained to be $$r_{0.05}<0.06$$ at 95% c.l., further improvements on this upper limit are hindered by polarized galactic foreground emissions and removal of gravitational lensing polarization. The 30/40 GHz receiver of the BICEP Array (BA) will deploy at the end of 2019 and will constrain the synchrotron foreground with unprecedented accuracy within the BK sky patch. We will show the design of the 30/40 GHz detectors and test results summarizing its performance. The low optical and atmospheric loading at these frequencies requires our TES detectors to have low saturation power in order to be photon noise dominated. To realize the low thermal conductivity required from a 250 mK base temperature, we developed new bolometer leg designs. We will present the relevant measured detector parameters: $$G, T_c, R_n, P_{sat}$$, and spectral bands, and noise spectra. We achieved a per bolometer NEP including all noise components of 2.07×10^-17W/$$\sqrt{Hz}$$, including an anticipated photon noise level 1.54×10^-17W/$$\sqrt{Hz}$$.

• Research Organization: SLAC National Accelerator Lab., Menlo Park, CA (United States)
• Sponsoring Organization: USDOE
• Contributing Organization: The Keck Array and BICEP2 Collaborations
• Grant/Contract Number: AC02-76SF00515; 06-ARPA206-0040; 10-SAT10-0017; 12-SAT12-0031; 14-SAT14-0009; 16-SAT16-0002.; 0742818; 0742592; 1044978; 1110087; 1145172; 1145143; 1145248; 1639040; 1638957; 1638978; 1638970; 1726917
• OSTI ID: 1608641
• Journal Information: Journal of Low Temperature Physics, Vol. 199, Issue 3-4; ISSN 0022-2291
• Publisher: Springer
• Country of Publication: United States
• Language: English

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