We study the propagation of a specific class of instrumental systematics to the reconstruction of the
B
-mode power spectrum of the cosmic microwave background (CMB). We focus on the non-idealities ...of the half-wave plate (HWP), a polarization modulator that is to be deployed by future CMB experiments, such as the phase-A satellite mission LiteBIRD. We study the effects of non-ideal HWP properties, such as transmittance, phase shift, and cross-polarization. To this end, we developed a simple, yet stand-alone end-to-end simulation pipeline adapted to LiteBIRD. We analyzed the effects of a possible mismatch between the measured frequency profiles of HWP properties (used in the mapmaking stage of the pipeline) and the actual profiles (used in the sky-scanning step). We simulated single-frequency, CMB-only observations to emphasize the effects of non-idealities on the BB power spectrum. We also considered multi-frequency observations to account for the frequency dependence of HWP properties and the contribution of foreground emission. We quantified the systematic effects in terms of a bias Δ
r
on the tensor-to-scalar ratio,
r
, with respect to the ideal case without systematic effects. We derived the accuracy requirements on the measurements of HWP properties by requiring Δ
r
< 10
−5
(1% of the expected LiteBIRD sensitivity on
r
). Our analysis is introduced by a detailed presentation of the mathematical formalism employed in this work, including the use of the Jones and Mueller matrix representations.
Used for both proton decay searches and neutrino physics, large water Cherenkov (WC) detectors have been very successful tools in particle physics. They are notable for their large masses and charged ...particle detection capabilities. While current WC detectors reconstruct charged particle tracks over a wide energy range, they cannot efficiently detect neutrons. Gadolinium (Gd) has the largest thermal neutron capture cross section of all stable nuclei and produces an 8 MeV gamma cascade that can be detected with high efficiency. Because of the many new physics opportunities that neutron tagging with a Gd salt dissolved in water would open up, a large-scale R&D program called EGADS was established to demonstrate this technique’s feasibility. EGADS features all the components of a WC detector, chiefly a 200-ton stainless steel water tank furnished with 240 photo-detectors, DAQ, and a water system that removes all impurities from water while keeping Gd in solution. In this paper we discuss the milestones towards demonstrating the feasibility of this novel technique, and the features of EGADS in detail.
We laser-ablated sub-wavelength structures (SWS) on 200 mm diameter birefringent sapphire disks to produce broadband anti-reflection coating (ARC). The disks were assembled into a stack of five ...plates making an achromatic half-wave plate (AHWP) suitable for operation between 40 and 140 GHz. We report on the SWS fabrication and transmission measurements of the stack at room temperature. From the measurements, we compute a band average transmission and modulation efficiency for nine spectral bands that correspond to the frequency coverage of the
LiteBIRD
Low-Frequency Telescope (LFT). We also assess the level of instrumental polarization the AHWP exhibits. We discuss paths for further development to minimize the instrumental polarization from the AHWP. This work is a development milestone toward the implementation of an AHWP for the
LiteBIRD
satellite.
•We demonstrate a novel Pb-free die-attachment structure using Sn-plated Zn solder.•The bonded microstructure can be controlled by the process time.•The current bonding structure shows high bonding ...strength above 30MP.•The fracture of current bonding system occurred in the β-Sn matrix soldered layer.•The β-Sn phase in the fracture layer can be expected to reduce the brittleness of Zn.
A novel die-attachment method is demonstrated through quasi-transient liquid-phase bonding using Sn-plated Zn sheets. The bonding temperature can be decreased to 250°C, which is ∼100°C lower than that for typical Zn–Sn high-temperature solders. The bonded interface consists of primary α-Zn and Sn–Zn eutectic phases, and the microstructure can be controlled according to the diffusion velocities of metals. The high die-shear strength exceeding 30MPa from the controlled microstructure is superior to typical Pb–5Sn solders strength around 20MPa.
OBJECTIVES: The objectives of this study were to establish a magnetic resonance imaging‐based classification system for canine hyperadrenocorticism according to pituitary gland extension, determine ...indications for trans‐sphenoidal hypophysectomy, and clarify the prognosis for each disease grade. METHODS: A 5‐point classification system (Grades 1 to 5) was developed based on tumour extension in dorsal and cranio–caudal directions. Cases were then classified as Type A: no arterial circle of Willis or cavernous sinus involvement and Type B: cases in which these blood vessels were involved. RESULTS: Medical records and magnetic resonance imaging data of 37 cases with hyperadrenocorticism were reviewed. Thirty‐three cases underwent surgery; 4 Grade 5 cases did not have appropriate indications for surgery, and other therapies were used. Complete resection was achieved for 3, 3, 22 and 1 Grade 1A, 2A, 3A and 3B cases, respectively. Resection was incomplete in 1, 1 and 2 Grade 3A, 3B and 4B cases, respectively. Remission was achieved in 29 cases. Recurrence occurred in 4 cases, all of which were classified as Grade 3. CLINICAL SIGNIFICANCE: Dogs with Type A, Grade 1 to 3 hyperadrenocorticism had a good prognosis following trans‐sphenoidal hypophysectomy. Grade 3B, 4 and 5 cases may not be suitable for this surgery.
We present the development of a frequency-domain multiplexing readout of kinetic inductance detectors (KIDs) for pulse signals with a self-trigger system. The KIDs consist of an array of ...superconducting resonators that have different resonant frequencies individually, allowing us to read out multiple channels in the frequency domain with a single wire using a microwave-frequency comb. The energy deposited to the resonators break Cooper pairs, changing the kinetic inductance and, hence, the amplitude and the phase of the probing microwaves. For some applications such as X-ray detections, the deposited energy is detected as a pulse signal shaped by the time constants of the quasiparticle lifetime, the resonator quality factor, and the ballistic phonon lifetime in the substrate, ranging from microseconds to milliseconds. A readout system commonly used converts the frequency-domain data to the time-domain data. For the short pulse signals, the data rate may exceed the data transfer bandwidth, as the short time constant pulses require us to have a high sampling rate. In order to overcome this circumstance, we have developed a KID readout system that contains a self-trigger system to extract relevant signal data and reduces the total data rate with a commercial off-the-shelf FPGA board. We have demonstrated that the system can read out pulse signals of 15 resonators simultaneously with about 10 Hz event rate by irradiating
α
particles from
241
Am to the silicon substrate on whose surface aluminum KID resonators are formed.
We present a status of the development of microwave kinetic inductance detectors (MKIDs) for a detection of athermal phonons in a substrate. The energy deposited in the substrate is converted to ...athermal phonons. Athermal phonons arriving at the surface can break Cooper pairs in the MKIDs which are formed as a thin superconducting metal layer in the substrate surface. By counting the number of Cooper pairs broken and measuring the phonon arrival times, we can measure the amount of deposited energy and its position. MKIDs are suitable for the frequency-domain multiplexing readout, which enables us to readout hundreds of pixels simultaneously and, hence, to detect athermal phonons with a large detection efficiency. We fabricated MKIDs with a combination of aluminum and niobium on a silicon substrate, and then irradiated it with
α
particles from an
241
Am source. We detected phonons and made a rough estimation of the phonon propagation velocity of 1.1–1.3 km/s. We found that a thin insulator layer can block the phonon propagation from the substrate to the thin metal layer.
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