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.
The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status / Westbrook, B., Ade, P.A.R., Aguilar, M., Akiba, Y., Arnold, K., Baccigalupi, C., Barron, D., Beck, D., Beckman, S., Bender, A.N., Bianchini, F., Boettger, D., Borrill, J., Chapman, S., Chinone, Y., Coppi, G., Crowley, K., Cukierman, A., de Haan, T., Dünner, R., et al.. - In: JOURNAL OF LOW TEMPERATURE PHYSICS. - ISSN 0022-2291. - 193:5-6(2018), pp. 758-770. [10.1007/s10909-018-2059-0]
The POLARBEAR-2 and Simons Array Focal Plane Fabrication Status
Baccigalupi, C.;Bianchini, F.;Borrill, J.;Fabbian, G.;Jaffe, A.;Krachmalnicoff, N.;Poletti, D.;Puglisi, G.;Stompor, R.;Tikhomirov, A.;
2018-01-01
Abstract
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.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
