GroundBIRD: an experiment for CMB polarization measurements at a large angular scale from the ground

Tajima, O.; Choi, Jhoon; Hazumi, M.; Ishitsuka, H.; Kawai, M.; Yoshida, Mitsuhiro

doi:10.1117/12.925816

Cited by 19 publications

(17 citation statements)

References 11 publications

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“…Numerous ground-based and balloon-borne missions are under way to measure the large angular scale spectrum of the CMB polarization. [1][2][3] In addition, several space instruments have been proposed to realize the ultimate promise of CMB polarization science, most recently LiteBIRD 4 and COrE+. 5 The large format detector arrays needed for these missions must be compatible with the space environment.…”

Section: Introductionmentioning

confidence: 99%

Silicon-based antenna-coupled polarization-sensitive millimeter-wave bolometer arrays for cosmic microwave background instruments

et al. 2016

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We describe feedhorn-coupled polarization-sensitive detector arrays that utilize monocrystalline silicon as the dielectric substrate material. Monocrystalline silicon has a low-loss tangent and repeatable dielectric constant, characteristics that are critical for realizing efficient and uniform superconducting microwave circuits. An additional advantage of this material is its low specific heat. In a detector pixel, two Transition-Edge Sensor (TES) bolometers are antenna-coupled to in-band radiation via a symmetric planar orthomode transducer (OMT). Each orthogonal linear polarization is coupled to a separate superconducting microstrip transmission line circuit. On-chip filtering is employed to both reject out-of-band radiation from the upper band edge to the gap frequency of the niobium superconductor, and to flexibly define the bandwidth for each TES to meet the requirements of the application. The microwave circuit is compatible with multi-chroic operation. Metalized silicon platelets are used to define the backshort for the waveguide probes. This micro-machined structure is also used to mitigate the coupling of out-of-band radiation to the microwave circuit. At 40 GHz, the detectors have a measured efficiency of ∼90%. In this paper, we describe the development of the 90 GHz detector arrays that will be demonstrated using the Cosmology Large Angular Scale Surveyor (CLASS) ground-based telescope.

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Section: Introductionmentioning

confidence: 99%

Silicon-based antenna-coupled polarization-sensitive millimeter-wave bolometer arrays for cosmic microwave background instruments

et al. 2016

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“…The target sensitivity is to constrain the tensor-to-scalar ratio r with a precision of σ r ∼ 0.01 with three year observation [7]. To achieve high enough sensitivity to observe B-modes for large sky coverage, we employ three features: fast rotation scanning, microwave kinetic inductance detector (MKID) and cold optics [6].…”

Section: Overview Of Groundbirdmentioning

confidence: 99%

“…GroundBIRD is aiming to measure the B-modes of CMB polarization [6]. The observation site is Teide observatory.…”

Section: Introductionmentioning

confidence: 99%

GroundBIRD: A CMB Polarization Experiment with MKID Arrays

Lee

Choi²,

Génova-Santos

et al. 2020

J Low Temp Phys

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GroundBIRD is a ground-based experiment for the precise observation of the polarization of the cosmic microwave background (CMB). To achieve high sensitivity at large angular scale, we adopt three features in this experiment: fast rotation scanning, microwave kinetic inductance detector (MKID) and cold optics. The rotation scanning strategy has the advantage to suppress 1/ f noise. It also provides a large sky coverage of 40%, which corresponds to the large angular scales of l ∼ 6. This allows us to constrain the tensor-to-scalar ratio by using low l B-mode spectrum. The focal plane consists of 7 MKID arrays for two target frequencies, 145 GHz and 220 GHz band. There are 161 pixels in total, of which 138 are for 144 GHz and 23 are for 220 GHz. This array is currently under development and the prototype will soon be evaluated in telescope. The GroundBIRD telescope will observe the CMB at the Teide observatory. The telescope was moved from Japan to Tenerife and is now under test. We present the status and plan of the GroundBIRD experiment.

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“…We have developed such technology that continuously maintains a cold condition a) shugo@post.kek.jp on a rotating system for long periods without frequent maintenance. We are motivated to use the technology for a radio telescope observing the cosmic microwave background (CMB) 6 . In this paper, we describe the developed system and its performance.…”

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confidence: 99%

Cryogenic cooling with cryocooler on a rotating system

Oguri

Choi

Kawai

et al. 2013

Review of Scientific Instruments

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We developed a system that continuously maintains a cryocooler for long periods on a rotating table. A cryostat that holds the cryocooler is set on the table. A compressor is located on the ground and supplies high-purity (>99.999%) and high-pressure (1.7 MPa) helium gas and electricity to the cryocooler. The operation of the cryocooler and other instruments requires the development of interface components between the ground and rotating table. A combination of access holes at the center of the table and two rotary joints allows simultaneous circulation of electricity and helium gas. The developed system provides two innovative functions under the rotating condition, cooling from room temperature and the maintenance of a cold condition for long periods. We have confirmed these abilities as well as temperature stability under a condition of continuous rotation at 20 rpm. The developed system can be applied in various fields, e.g., in tests of Lorentz invariance, searches for axion, radio astronomy, and cosmology, and application of radar systems. In particular, there is a plan to use this system for a radio telescope observing cosmic microwave background radiation.

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GroundBIRD: an experiment for CMB polarization measurements at a large angular scale from the ground

Cited by 19 publications

References 11 publications

Silicon-based antenna-coupled polarization-sensitive millimeter-wave bolometer arrays for cosmic microwave background instruments

Silicon-based antenna-coupled polarization-sensitive millimeter-wave bolometer arrays for cosmic microwave background instruments

GroundBIRD: A CMB Polarization Experiment with MKID Arrays

Cryogenic cooling with cryocooler on a rotating system

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