Simulations of systematic effects arising from cosmic rays in the LiteBIRD space telescope, and effects on the measurements of CMB B-modes

Stever, S.; Ghigna, Tommaso; Tominaga, M.; Puglisi, Giuseppe; Tsujimoto, Masahiro; Marazzini, M. Zeccoli; Baratto, M.; Tomasi, M.; Minami, Y.; Sugiyama, S.; Kato, A.; Matsumura, Tomotake; Ishino, H.; Patanchon, G.; Hazumi, M.

doi:10.1088/1475-7516/2021/09/013

Cited by 7 publications

(3 citation statements)

References 26 publications

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“…Simulations in COMSOL suggest that the presence of a normal metal such Pd or Au on the backside of the wafer will drastically reduce any signals in the TES as a result of a cosmic ray striking the substrate. 18 This presents a technical tension between coating the backside of the wafer with a normal metal while keeping the wafer optically transparent where the light from the telescope must pass through the wafer to stimulate the sinuous antenna. As such we have developed a Backside Cosmic Ray Mitigation Layer (BCRML) to solve this issue.…”

Section: Backside Palladium Depositionmentioning

confidence: 99%

“…Simulation work from 18 suggest that a layer of normal metal deposited on the backside of the device wafer should be effective at reducing the amplitude and rate of cosmic ray signals seen in bolometers. The primary effect comes from the heat capacity and thermal conductivity of the Pd which helps keep the temperature of the substrate stable with minimal thermal gradients that could be caused by incident cosmic rays.…”

Section: Cosmic Ray Testingmentioning

confidence: 99%

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Development of the low frequency telescope focal plane detector modules for LiteBIRD

Westbrook¹,

Raum²,

Lee³

et al. 2022

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI

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LiteBIRD is a JAXA-led strategic large-class satellite mission designed to measure the polarization of the cosmic microwave background and Galactic foregrounds from 34 to 448 GHz across the entire sky from L2 in the late 2020s. The scientific payload includes three telescopes which are called the low-, mid-, and high-frequency telescopes each with their own receiver that covers a portion of the mission's frequency range. The low frequency telescope will map synchrotron radiation from the Galactic foreground and the cosmic microwave background. We discuss the design, fabrication, and characterization of the low-frequency focal plane modules for low-frequency telescope, which has a total bandwidth ranging from 34 to 161 GHz. There will be a total of 4 different pixel types with 8 overlapping bands to cover the full frequency range. These modules are housed in a single low-frequency focal plane unit which provides thermal isolation, mechanical support, and radiative baffling for the detectors. The module design implements multi-chroic lenslet-coupled sinuous antenna arrays coupled to transition edge sensor bolometers read out with frequencydomain mulitplexing. While this technology has strong heritage in ground-based cosmic microwave background experiments, the broad frequency coverage, low optical loading conditions, and the high cosmic ray background of the space environment require further development of this technology to be

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Section: Backside Palladium Depositionmentioning

confidence: 99%

Section: Cosmic Ray Testingmentioning

confidence: 99%

Development of the low frequency telescope focal plane detector modules for LiteBIRD

Westbrook¹,

Raum²,

Lee³

et al. 2022

Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI

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“…An early result is described in a series of two articles. One is by Stever et al, 5 which describes the overview of this study and covers the details of the simulation from the CR spectrum to the Time-Ordered Data (TOD) and predicted ∆r. This article covers the details of the simulation from the TOD to sky maps and power spectrum.…”

Section: Introductionmentioning

confidence: 99%

Simulation of the cosmic ray effects for the LiteBIRD satellite observing the CMB B-mode polarization

Tominaga,

Tsujimoto,

Stever

et al. 2021

Preprint

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The LiteBIRD satellite is planned to be launched by JAXA in the late 2020s. Its main purpose is to observe the large-scale B-mode polarization in the Cosmic Microwave Background (CMB) anticipated from the Inflation theory. LiteBIRD will observe the sky for three years at the second Lagrangian point (L2) of the Sun-Earth system. Planck was the predecessor for observing the CMB at L2, and the onboard High Frequency Instrument (HFI) suffered contamination by glitches caused by the cosmic-ray (CR) hits. We consider the CR hits can also be a serious source of the systematic uncertainty for LiteBIRD. Thus, we have started a comprehensive end-toend simulation study to assess impact of the CR hits for the LiteBIRD detectors. Here, we describe procedures to make maps and power spectra from the simulated time-ordered data, and present initial results. Our initial estimate is that C BB l by CR is ∼ 2 × 10 −6 µK 2 CMB in a one-year observation with 12 detectors assuming that the noise is 1 aW/ √ Hz for the differential mode of two detectors constituting a polarization pair.

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Design of the On-Board Data Compression for the Bolometer Data of LiteBIRD

Tominaga

Tsujimoto²,

Smecher³

et al. 2022

J Low Temp Phys

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LiteBIRD is a space-borne experiment dedicated to detecting large-scale B-mode anisotropies in the linear polarization of the Cosmic Microwave Background (CMB) predicted by the theory of inflation. It is planned to be launched in the late 2020s to the second Lagrange point (L2) of the Sun-Earth system. LiteBIRD will map the sky in 15 frequency bands. In comparison to Planck HFI, the previous low-temperature bolometer-based satellite for CMB observations, the number of detector has increased by two orders of magnitude, up to ∼5000 detectors in total. The data rate is 19 Hz from each detector. The bandpass to the ground is limited to 10 Mbps using the X-band for a few hours per day. These require the data to be compressed by more than 50%. The exact value depends on how much information entropy is contained in the real data. We have thus evaluated the compression by simulating the time-ordered data of polarization sensitive bolometers. The foreground emission, detector noise, cosmic ray glitches, leakage from the CMB intensity to polarization, etc. are simulated. We investigated several algorithms and demonstrated that the required compression ratio can be achieved by some of them. We describe the details of this evaluation and propose algorithms that can be employed in the on-board digital electronics of LiteBIRD.

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Simulations of systematic effects arising from cosmic rays in the LiteBIRD space telescope, and effects on the measurements of CMB B-modes

Cited by 7 publications

References 26 publications

Development of the low frequency telescope focal plane detector modules for LiteBIRD

Development of the low frequency telescope focal plane detector modules for LiteBIRD

Simulation of the cosmic ray effects for the LiteBIRD satellite observing the CMB B-mode polarization

Design of the On-Board Data Compression for the Bolometer Data of LiteBIRD

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