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The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status

  • Author(s): Westbrook, B
  • Ade, PAR
  • Aguilar, M
  • Akiba, Y
  • Arnold, K
  • Baccigalupi, C
  • Barron, D
  • Beck, D
  • Beckman, S
  • Bender, AN
  • Bianchini, F
  • Boettger, D
  • Borrill, J
  • Chapman, S
  • Chinone, Y
  • Coppi, G
  • Crowley, K
  • Cukierman, A
  • de Haan, T
  • Dünner, R
  • Dobbs, M
  • Elleflot, T
  • Errard, J
  • Fabbian, G
  • Feeney, SM
  • Feng, C
  • Fuller, G
  • Galitzki, N
  • Gilbert, A
  • Goeckner-Wald, N
  • Groh, J
  • Halverson, NW
  • Hamada, T
  • Hasegawa, M
  • Hazumi, M
  • Hill, CA
  • Holzapfel, W
  • Howe, L
  • Inoue, Y
  • Jaehnig, G
  • Jaffe, A
  • Jeong, O
  • Kaneko, D
  • Katayama, N
  • Keating, B
  • Keskitalo, R
  • Kisner, T
  • Krachmalnicoff, N
  • Kusaka, A
  • Le Jeune, M
  • Lee, AT
  • Leon, D
  • Linder, E
  • Lowry, L
  • Madurowicz, A
  • Mak, D
  • Matsuda, F
  • May, A
  • Miller, NJ
  • Minami, Y
  • Montgomery, J
  • Navaroli, M
  • Nishino, H
  • Peloton, J
  • Pham, A
  • Piccirillo, L
  • Plambeck, D
  • Poletti, D
  • Puglisi, G
  • Raum, C
  • Rebeiz, G
  • Reichardt, CL
  • Richards, PL
  • Roberts, H
  • Ross, C
  • Rotermund, KM
  • Segawa, Y
  • Sherwin, B
  • Silva-Feaver, M
  • Siritanasak, P
  • Stompor, R
  • Suzuki, A
  • Tajima, O
  • Takakura, S
  • Takatori, S
  • Tanabe, D
  • Tat, R
  • Teply, GP
  • Tikhomirov, A
  • Tomaru, T
  • Tsai, C
  • Whitehorn, N
  • Zahn, A
  • et al.
Abstract

© 2018, Springer Science+Business Media, LLC, part of Springer Nature. We present on the status of POLARBEAR-2 A (PB2-A) focal plane fabrication. The PB2-A is the first of three telescopes in the Simons Array, which is an array of three cosmic microwave background polarization-sensitive telescopes located at the POLARBEAR site in Northern Chile. As the successor to the PB experiment, each telescope and receiver combination is named as PB2-A, PB2-B, and PB2-C. PB2-A and -B will have nearly identical receivers operating at 90 and 150 GHz while PB2-C will house a receiver operating at 220 and 270 GHz. Each receiver contains a focal plane consisting of seven close-hex packed lenslet-coupled sinuous antenna transition edge sensor bolometer arrays. Each array contains 271 dichroic optical pixels, each of which has four TES bolometers for a total of 7588 detectors per receiver. We have produced a set of two types of candidate arrays for PB2-A. The first we call Version 11 (V11) uses a silicon oxide (SiO x ) for the transmission lines and crossover process for orthogonal polarizations. The second we call Version 13 (V13) uses silicon nitride (SiN x ) for the transmission lines and cross-under process for orthogonal polarizations. We have produced enough of each type of array to fully populate the focal plane of the PB2-A receiver. The average wirebond yield for V11 and V13 arrays is 93.2% and 95.6%, respectively. The V11 arrays had a superconducting transition temperature (T c ) of 452±15 mK, a normal resistance (R n ) of 1.25±0.20Ω, and saturation powers of 5.2 ± 1.0 pW and 13 ± 1.2 pW for the 90 and 150 GHz bands, respectively. The V13 arrays had a superconducting transition temperature (T c ) of 456 ± 6 mK, a normal resistance (R n ) of 1.1±0.2Ω, and saturation powers of 10.8 ± 1.8 pW and 22.9 ± 2.6 pW for the 90 and 150 GHz bands, respectively. Production and characterization of arrays for PB2-B are ongoing and are expected to be completed by the summer of 2018. We have fabricated the first three candidate arrays for PB2-C but do not have any characterization results to present at this time.

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