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1. BICEP Array: 150 GHz detector module development

   https://doi.org/10.48550/ARXIV.2111.14785  

   Schillaci, A. ; Ade, P. A. ; Ahmed, Z. ; Amiri, M. ; Barkats, D. ; Basu Thakur, R. ; Bischoff, C. A. ; Beck, D. ; Bock, J. J. ; Buza, V. ; et al ( November 2021 , Journal of low temperature physics)

   The BICEP/Keck Collaboration is currently leading the quest to the highest sensitivity measurements of the polarized CMB anisotropies on degree scale with a series of cryogenic telescopes, of which BICEP Array is the latest Stage-3 upgrade with a total of ∼32,000 detectors. The instrument comprises 4 receivers spanning 30 to 270 GHz, with the low-frequency 30/40 GHz deployed to the South Pole Station in late 2019. The full complement of receivers is forecast to set the most stringent constraints on the tensor to scalar ratio r. Building on these advances, the overarching small-aperture telescope concept is already being used as the reference for further Stage-4 experiment design. In this paper I will present the development of the BICEP Array 150 GHz detector module and its fabrication requirements, with highlights on the high-density time division multiplexing (TDM) design of the cryogenic circuit boards. The low-impedance wiring required between the detectors and the first-stage SQUID amplifiers is crucial to maintain a stiff voltage bias on the detectors. A novel multi-layer FR4 Printed Circuit Board (PCB) with superconducting traces, capable of reading out up to 648 detectors, is presented along with its validation tests. I will also describe an ultra-high density TDM detectormore »module we developed for a CMB-S4-like experiment that allows up to 1,920 detectors to be read out. TDM has been chosen as the detector readout technology for the Cosmic Microwave Background Stage-4 (CMB-S4) experiment based on its proven low-noise performance, predictable costs and overall maturity of the architecture. The heritage for TDM is rooted in mm- and submm-wave experiments dating back 20 years and has since evolved to support a multiplexing factor of 64x in Stage-3 experiments.« less
2. Design and characterization of new 90 GHz detectors for the Cosmology Large Angular Scale Surveyor (CLASS)

   https://doi.org/10.1117/12.2630081  

   Nunez, Carolina ; Appel, John W. ; Bruno, Sarah Marie ; Datta, Rahul ; Ali, Aamir ; Bennett, Charles L. ; Dahal, Sumit ; Denes Couto, Jullianna ; Denis, Kevin ; Eimer, Joseph ; et al ( August 2022 , Proceedings Volume 12190, Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy XI)

   Zmuidzinas, Jonas ; Gao, Jian-Rong (Ed.)

   The Cosmology Large Angular Scale Surveyor (CLASS) is a polarization-sensitive telescope array located at an altitude of 5,200 m in the Chilean Atacama Desert. CLASS is designed to measure "E-mode" (even parity) and "B-mode" (odd parity) polarization patterns in the Cosmic Microwave Background (CMB) over large angular scales with the aim of improving our understanding of inflation, reionization, and dark matter. CLASS is currently observing with three telescopes covering four frequency bands: one at 40 GHz (Q); one at 90 GHz (W1); and one dichroic system at 150/220 GHz (G). In these proceedings, we discuss the updated design and in-lab characterization of new 90 GHz detectors. The new detectors include design changes to the transition-edge sensor (TES) bolometer architecture, which aim to improve stability and optical efficiency. We assembled and tested four new detector wafers, to replace four modules of the W1 focal plane. These detectors were installed into the W1 telescope, and will achieve first light in the austral winter of 2022. We present electrothermal parameters and bandpass measurements from in-lab dark and optical testing. From in-lab dark tests, we also measure a median NEP of 12.3 aW√ s across all four wafers about the CLASS signal band, whichmore »is below the expected photon NEP of 32 aW√ s from the field. We therefore expect the new detectors to be photon noise limited.« less
3. Searching for RF-Only Triggered Cosmic Ray Events with the High-Elevation BEACON Prototype

   https://doi.org/10.22323/1.395.1084  

   Southall, Daniel ; Wissel, Stephanie ; Alvarez-Muniz, Jaime ; Carvalho Jr., Washington ; Cummings, Austin ; Curtis-Ginsberg, Zachery ; Deaconu, Cosmin ; Hughes, Kaeli ; Ludwig, Andrew ; Mulrey, Katharine ; et al ( March 2022 , Proceedings of 37th International Cosmic Ray Conference)

   The Beamforming Elevated Array for COsmic Neutrinos (BEACON) is a concept for a neutrino telescope designed to measure tau lepton air showers generated from tau neutrino interactions near the horizon. This detection mechanism provides a pure measurement of the tau flavor of cosmogenic neutrinos, which could be used to set limits on the observed flavor ratios for cosmogenic neutrinos in a manner complimentary to the all-flavor neutrino flux measurements made by other experiments. BEACON is expected to also be capable of detecting cosmic rays through RF-only triggers. BEACON aims to achieve this sensitivity by using mountaintop radio arrays of dual-polarized antennas operating in the 30-80 MHz band which utilize directional interferometric triggering. BEACON stations are designed to efficiently use a small amount of instrumentation, allowing for deployment in a variety of high-elevation sites. The interferometric trigger provides a natural tool for directional-based anthropogenic RFI rejection at the trigger level, broadening the list for potential station sites. The BEACON prototype has seen continuous design advancements towards improving the mechanical durability and scientific capabilities since its initial deployment at White Mountain Research Station in 2018. Here we present the current prototype’s sensitivity to RF-triggered cosmic-ray background signals. We also present the nextmore »generation prototype, which includes scintillating cosmic ray detectors, improved antennas, and refined calibration techniques.« less
4. Adjusting neutrino interaction models and evaluating uncertainties using NOvA near detector data

   https://doi.org/10.1140/epjc/s10052-020-08577-5  

   Acero, M. A. ; Adamson, P. ; Agam, G. ; Aliaga, L. ; Alion, T. ; Allakhverdian, V. ; Anfimov, N. ; Antoshkin, A. ; Asquith, L. ; Aurisano, A. ; et al ( December 2020 , The European Physical Journal C)

   Abstract The two-detector design of the NOvA neutrino oscillation experiment, in which two functionally identical detectors are exposed to an intense neutrino beam, aids in canceling leading order effects of cross-section uncertainties. However, limited knowledge of neutrino interaction cross sections still gives rise to some of the largest systematic uncertainties in current oscillation measurements. We show contemporary models of neutrino interactions to be discrepant with data from NOvA, consistent with discrepancies seen in other experiments. Adjustments to neutrino interaction models in GENIE are presented, creating an effective model that improves agreement with our data. We also describe systematic uncertainties on these models, including uncertainties on multi-nucleon interactions from a newly developed procedure using NOvA near detector data.
5. Reconstructing the neutrino energy for in-ice radio detectors: A study for the Radio Neutrino Observatory Greenland (RNO-G)

   https://doi.org/10.1140/epjc/s10052-022-10034-4  

   Aguilar, J. A. ; Allison, P. ; Beatty, J. J. ; Bernhoff, H. ; Besson, D. ; Bingefors, N. ; Botner, O. ; Bouma, S. ; Buitink, S. ; Carter, K. ; et al ( February 2022 , The European Physical Journal C)

   Since summer 2021, the Radio Neutrino Observatory in Greenland (RNO-G) is searching for astrophysical neutrinos at energies$${>10}$$$>10$ PeV by detecting the radio emission from particle showers in the ice around Summit Station, Greenland. We present an extensive simulation study that shows how RNO-G will be able to measure the energy of such particle cascades, which will in turn be used to estimate the energy of the incoming neutrino that caused them. The location of the neutrino interaction is determined using the differences in arrival times between channels and the electric field of the radio signal is reconstructed using a novel approach based on Information Field Theory. Based on these properties, the shower energy can be estimated. We show that this method can achieve an uncertainty of 13% on the logarithm of the shower energy after modest quality cuts and estimate how this can constrain the energy of the neutrino. The method presented in this paper is applicable to all similar radio neutrino detectors, such as the proposed radio array of IceCube-Gen2.