Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Design and characterization of the POLARBEAR-2b and POLARBEAR-2c cosmic
  microwave background cryogenic receivers   The POLARBEAR-2/Simons Array Cosmic Microwave Background (CMB) polarization
experiment is an upgrade and expansion of the existing POLARBEAR-1 (PB-1)
experiment, located in the Atacama desert in Chile. Along with the CMB
temperature and $E$-mode polarization anisotropies, PB-1 and the Simons Array
study the CMB $B$-mode polarization anisotropies produced at large angular
scales by inflationary gravitational waves, and at small angular scales by
gravitational lensing. These measurements provide constraints on various
cosmological and particle physics parameters, such as the tensor-to-scalar
ratio $r$, and the sum of the neutrino masses. The Simons Array consists of
three 3.5 m diameter telescopes with upgraded POLARBEAR-2 (PB-2) cryogenic
receivers, named PB-2a, -2b, and -2c. PB-2a and -2b will observe the CMB over
multiple bands centered at 95 GHz and 150 GHz, while PB-2c will observe at 220
GHz and 270 GHz, which will enable enhanced foreground separation and
de-lensing. Each Simons Array receiver consists of two cryostats which share
the same vacuum space: an optics tube containing the cold reimaging lenses and
Lyot stop, infrared-blocking filters, and cryogenic half-wave plate; and a
backend which contains the focal plane detector array, cold readout components,
and millikelvin refrigerator. Each PB-2 focal plane array is comprised of 7,588
dual-polarization, multi-chroic, lenslet- and antenna-coupled, Transition Edge
Sensor (TES) bolometers which are cooled to 250 mK and read out using
Superconducting Quantum Interference Devices (SQUIDs) through a digital
frequency division multiplexing scheme with a multiplexing factor of 40. In
this work we describe progress towards commissioning the PB-2b and -2c
receivers including cryogenic design, characterization, and performance of both
the PB-2b and -2c backend cryostats.

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The categories of this paper are: q-fin
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The categories of this paper are: acc-phys
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The categories of this paper are: adap-org
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The categories of this paper are: ao-sci
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-lat
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The categories of this paper are: eess
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The categories of this paper are: cs
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The categories of this paper are: funct-an
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The categories of this paper are: alg-geom
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The categories of this paper are: comp-gas
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The categories of this paper are: q-alg
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The categories of this paper are: hep-ph
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The categories of this paper are: stat
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The categories of this paper are: plasm-ph
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The categories of this paper are: hep-th