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The MIllimeter Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs, MISTRAL, is a cryogenic LEKID camera, operating in the W band ( 77 - 103 GHz ) from the Gregorian focus of the 64-m aperture Sardinia Radio Telescope (SRT), in Italy. This instrument features a high angular resolution ( ∼ 12 arcsec ) and a wide instantaneous field of view ( ∼ 4 arcmin ), allowing continuum surveys of the mm-wave sky with many scientific targets, including observations of galaxy clusters via the Sunyaev–Zel'dovich effect. In May 2023, MISTRAL has been installed at SRT for the technical commissioning. In this contribution, we will describe the MISTRAL instrument focusing on the laboratory characterization of its focal plane: a ∼ 400 -pixel LEKID array. We will show the optical performance of the detectors highlighting the procedure for the identification of the pixels on the focal plane, the measurements of the optical responsivity and NEP, and the estimation of the optical efficiency. [ABSTRACT FROM AUTHOR]

The White Blood Cell (WBC) differential test ranks as the second most frequently performed diagnostic assay. It requires manual confirmation of the peripheral blood smear by experts to identify signs of abnormalities. Automated digital microscopy has emerged as a solution to reduce this labor-intensive process and improve efficiency. Several publicly available datasets provide various WBC subtypes of differing quality and resolution. These datasets have contributed to advancing WBC classification using machine learning techniques. However, digital microscopy of blood cells with high magnification often requires a wider depth of field, posing challenges for automatic digital microscopy that necessitates capturing multiple stacks of focal planes to obtain complete images of specific blood cells. Our dataset provides 25,773 image stacks from 72 patients. The image labels consist of 18 classes encompassing normal and abnormal cells, with two experts reviewing each label. Each image includes 10 z-stacks of cropped 200 by 200 pixel images, captured using a 50X microscope with 400 nm intervals. This study presents a comprehensive multi-focus dataset for WBC classification. [ABSTRACT FROM AUTHOR]

The application of CdZnTe(CZT) crystals in infrared focal plane detectors and x-ray imaging detectors is hindered by the low infrared transmittance (IRT) and the presence of Cd/Te inclusions/precipitation. Over the preceding decades, strategies involving Cd vapor control during the growth process and substrate post-annealing have been posited to address these challenges. Presently, the prioritized approach is the utilization of substrate post-annealing, owing to the limited precision in comprehending the Cd-Te equilibrium and the intricacies associated with Cd vapor control technology. This study delves into the effect of the removed surface layer depth of a CZT and the selection of the (111) A-face or (111) B-face on IRT during Cd atmosphere annealing. It is recommended that a minimum of 60 μm of the surface layer be eliminated using chemical mechanical polishing technology before annealing. Experimental findings further reveal that Cd atom diffusion from the (111) A-face results in an IRT enhancement of up to 60%, in stark contrast to the slight improvement observed with the (111) B-face after annealing. The mechanism of Cd atom diffusions affecting the IRT in the annealing process is discussed. [ABSTRACT FROM AUTHOR]

Keyhole laser-based processes have been adopted widely due to the high-quality welds and cuts that they produce and the accurately controlled dimensions of the end part. Fast-running simulation tools are required in order to estimate the dependence of process outputs, efficiency, and stability on the process variables. This work presents a fast-running simulation tool for keyhole laser-based processes with inert or no assisting gas that takes into account the effect of laser beam defocusing and the alteration of the effective reflectivity of the material due to the keyhole cavity. The model is built upgrading a successful model for the thermal phenomena based on finite differences and the enthalpy method. The presented model is compared to experimental results for the laser cutting process with both CO 2 and fiber laser sources and inert assisting gas. The model accurately predicts cutting depth and kerf, heat-affected zone width, and the dependence of the cutting depth on the position of the focal plane. The model manages to achieve reduced computational time enabling its utilization in process digital twins. [ABSTRACT FROM AUTHOR]

The bioinspired camera, comprising a single lens and a curved image sensor—a photodiode array on a curved surface—, was born of flexible electronics. Its economical build lends itself well to space-constrained machine vision applications. The curved sensor, much akin to the retina, helps image focusing, but the curvature also creates a problem of image distortion, which can undermine machine vision tasks such as object recognition. Here we report an anti-distortion single-lens camera, where 4096 silicon photodiodes arrayed on a curved surface in a nonuniform pattern assimilated to the distorting optics are the key to anti-distortion engineering. That is, the photo-pixel distribution pattern itself is warped in the same manner as images are warped, which correctively reverses distortion. Acquired images feature no appreciable distortion across a 120° horizontal view, as confirmed by their neural-network recognition accuracies. This distortion correction via photo-pixel array reconfiguration is a form of in-sensor computing. Curvature of image sensors that match the focal plane of the lens facilitate focussing but can cause image distortion. Here, an anti-distortion single-lens camera was developed using a curved image sensor with a photo-pixel distribution pattern warped like image warping to correctively reverse distortion. [ABSTRACT FROM AUTHOR]

We report on the effects of cosmic ray interactions with the kinetic inductance detector (KID)-based focal plane array for the terahertz intensity mapper (TIM). TIM is a NASA-funded balloon-borne experiment designed to probe the peak of the star formation in the Universe. It employs two spectroscopic bands, each equipped with a focal plane of four ∼ 900-pixel, KID-based array chips. Measurements of an 864-pixel TIM array show 791 resonators in a 0.5 GHz bandwidth. We discuss challenges with resonator calibration caused by this high multiplexing density. We robustly identify the physical positions of 788 (99.6 %) detectors using a custom LED-based identification scheme. Using this information, we show that cosmic ray events occur at a rate of 2.1 events / min / cm 2 in our array. 66 % of the events affect a single pixel, and other 33 % affect < 5 KIDs per event spread over a 0.66 cm 2 region (2 pixel pitches in radius). We observe a total cosmic ray dead fraction of 0.0011 % and predict that the maximum possible in-flight dead fraction is ∼ 0.124 %, which demonstrates our design will be robust against these high-energy events. [ABSTRACT FROM AUTHOR]

We are studying and developing high-performance spectroscopy solutions in silicon technology in the framework of instrumental developments around the B-BOP bolometer arrays and in the continuation of the former developments of the Herschel space telescope instruments and in particular its photodetector array camera and spectrometer. The integration of multiwavelength spectroscopic capabilities close to the array of a cooled bolometer would make it possible to detect the interstellar medium continuum by scanning and to trace its evolution, particularly by the detection of characteristic lines such as the cooling line [CII] at 158 µm. In this paper, we present the first concept under development and the preliminary results obtained from our cryogenic optical test bench. This solution is a tunable Fabry–Perot cavity with silicon mirrors driven by a cryogenic piezoelectric mechanism with a nanometric step. Each mirror is a dielectric Bragg structure, a stack of quarter-wave layers of silicon and air providing high reflectivity without metal loss. This solution allows extremely accurate scanning around a targeted wavelength. The first prototype cannot be integrated on a focal plane as it stands, and future optimizations integrating miniaturized scanning systems will make the system much more compact. [ABSTRACT FROM AUTHOR]

The Simons Observatory (SO) is a cosmic microwave background instrumentation suite in the Atacama Desert of Chile. More than 65,000 polarization-sensitive transition-edge sensor (TES) bolometers will be fielded in the frequency range spanning 27 to 280 GHz, with three separate dichroic designs. The mid-frequency 90/150 GHz and ultra-high-frequency 220/280 GHz detector arrays, fabricated at NIST, account for 39 of 49 total detector modules and implement the feedhorn-fed orthomode transducer-coupled TES bolometer architecture. A robust production-level fabrication framework for these detector arrays and the monolithic DC/RF routing wafers has been developed, which includes single device prototyping, process monitoring techniques, in-process metrology, and cryogenic measurements of critical film properties. Application of this framework has resulted in timely delivery of nearly 100 total superconducting focal plane components to SO with 88 % of detector wafers meeting nominal criteria for integration into a detector module: a channel yield > 95 % and T c in the targeted range. [ABSTRACT FROM AUTHOR]

We present the optical characterization of two-scale hierarchical phased-array antenna kinetic inductance detectors (KIDs) for millimeter/submillimeter wavelengths. Our KIDs have a lumped-element architecture with parallel plate capacitors and aluminum inductors. The incoming light is received with a hierarchical phased array of slot dipole antennas, split into 4 frequency bands (between 125 GHz and 365 GHz) with on-chip lumped-element band-pass filters, and routed to different KIDs using microstriplines. Individual pixels detect light for the 3 higher-frequency bands (190–365 GHz), and the signals from four individual pixels are coherently summed to create a larger pixel detecting light for the lowest frequency band (125–175 GHz). The spectral response of the band-pass filters was measured using Fourier transform spectroscopy (FTS), the far-field beam pattern of the phased-array antennas was obtained using an infrared source mounted on a 2-axis translating stage, and the optical efficiency of the KIDs was characterized by observing loads at 294 K and 77 K. We report on the results of these three measurements. [ABSTRACT FROM AUTHOR]

Time-division multiplexing is the readout architecture of choice for many ground and space experiments, as it is a very mature technology with proven outstanding low-frequency noise stability, which represents a central challenge in multiplexing. Once fully populated, each of the two BICEP Array high-frequency receivers, observing at 150 GHz and 220/270 GHz, will have 7776 TES detectors tiled on the focal plane. The constraints set by these two receivers required a redesign of the warm readout electronics. The new version of the standard multichannel electronics, developed and built at the University of British Columbia, is presented here for the first time. BICEP Array operates time-division multiplexing readout technology to the limits of its capabilities in terms of multiplexing rate, noise and cross talk, and applies them in rigorously demanding scientific application requiring extreme noise performance and systematic error control. Future experiments like CMB-S4 plan to use TES bolometers with time-division/SQUID-based readout for an even larger number of detectors. [ABSTRACT FROM AUTHOR]

The Europa Thermal Emission Imaging System (E-THEMIS) on the Europa Clipper spacecraft will investigate the temperature and physical properties of Europa using thermal infrared (TIR) images in three wavelength bands centered from 7-14 μm, 14-28 μm and 28-80 μm. E-THEMIS will map >80% of the surface Europa at multiple times of day at a resolution of 8-km per pixel, ∼32% percent of the surface at ≤1 km/pixel resolution, and ∼6% percent at ≤100 m/pixel resolution. The specific objectives of the investigation are to 1) understand the formation of surface features, including sites of recent or current geologic activity, in order to understand regional and global processes and evolution and 2) to identify safe sites for future landed missions. E-THEMIS uses an uncooled microbolometer detector array for the IR focal plane. The E-THEMIS focal plane has 920 cross-track pixels (896 active) and 140 along-track pixels in each of the three spectral bands. The image data are collected at 14-bits per pixel at a frame rate of 60 Hz. The instrument can operate in framing mode, where full frame images are collected, and optionally co-added in time, in each band, or in time-delay-integration (TDI) mode where consecutive rows from each band are offset spatially to remove the spacecraft motion and then summed. In addition, the data in each band can be spatially aggregated from 2 × 2 to 5 × 5 pixels. These modes will be varied throughout each Europa flyby to optimize the data precision while fitting within the E-THEMIS data allocation. The expected temperature precision, measured as the noise equivalent spectral radiance, is 1.2 K at scene temperatures ≥90 K for a TDI of 16 with 4 × 4 pixel coaggregation in Band 2. The absolute accuracy at 90 K is 2−3 K in Band 2. E-THEMIS is an all-reflective, three-mirror anastigmat telescope with a 6.45-cm effective aperture and a speed of f/1.34 cross-track and 1.92 along-track. The mass of instrument Sensor Assembly, mounted on the spacecraft nadir deck, is 11.4 kg, the vault electronics are 1.8 kg, and the two are connected through a 3.1 kg harness. The Sensor volume is 23.7 cm x 31.8 cm x 29.8 cm. E-THEMIS consumes an average operation power of 34.8 W at 28 V. E-THEMIS was developed by Arizona State University with Raytheon Vision Systems developing the microbolometer focal plane assembly and Ball Aerospace developing the electronics. E-THEMIS was integrated, tested, and radiometrically calibrated on the Arizona State University campus in Tempe, AZ. [ABSTRACT FROM AUTHOR]

Efficient fiber-chip coupling interfaces are critically important for integrated photonics. Since surface gratings diffract optical signals vertically out of the chip, these couplers can be placed anywhere in the circuit allowing for wafer-scale testing. While state-of-the-art grating couplers have been developed for silicon-on-insulator (SOI) waveguides, the moderate index contrast of silicon nitride (SiN) presents an outstanding challenge for implementing efficient surface grating couplers on this platform. Due to the reduced grating strength, a longer structure is required to radiate the light from the chip which produces a diffracted field that is too wide to couple into the fiber. In this work, we present a novel grating coupler architecture for silicon nitride photonic integrated circuits that utilizes an amorphous silicon (α-Si) overlay. The high refractive index of the α-Si overlay breaks the coupler's vertical symmetry which increases the directionality. We implement subwavelength metamaterial apodization to optimize the overlap of the diffracted field with the optical fiber Gaussian mode profile. Furthermore, the phase of the diffracted beam is engineered to focalize the field into an SMF-28 optical fiber placed 55 µm above the surface of the chip. The coupler was designed using rigorous three-dimensional (3D) finite-difference time-domain (FDTD) simulations supported by genetic algorithm optimization. Our grating coupler has a footprint of 26.8 × 32.7 µm2 and operates in the O-band centered at 1.31 μm. It achieves a high directionality of 85% and a field overlap of 90% with a target fiber mode size of 9.2 µm at the focal plane. Our simulations predict a peak coupling efficiency of − 1.3 dB with a 1-dB bandwidth of 31 nm. The α-Si/SiN grating architecture presented in this work enables the development of compact and efficient optical interfaces for SiN integrated photonics circuits with applications including optical communications, sensing, and quantum photonics. [ABSTRACT FROM AUTHOR]

Exactly converging the metal powder flux at a given substrate position is of great importance for additively manufacturing high-quality metallic products, and it essentially depends on the geometric structure and thermal dynamics of powder streams. In this study, we developed a 3D numerical model to elucidate the interactions between powder, gas, and laser beam in a coaxial nozzle during laser directed energy deposition (DED). The numerical simulation indicates that the waist-shaped powder stream converges approximately 11.2 mm below the nozzle outlet, where the minimum nominal radius is achieved. Within the laser irradiation area, the powder particle temperature increases dramatically and reaches the maximum average value at approximately 20 mm away from the nozzle outlet. Furthermore, optimal powder stream convergence and high thermal efficiency can be achieved when the powder stream driven by low inner gas flow rate converges 4 mm below the laser beam focal plane. The results of high-speed and infrared imaging analysis demonstrate that the proposed model has good predictability for the mean particle velocity and temperature, with average R2 of 0.91 and 0.96, respectively. This study provides an effective approach to achieve desired metal-powder stream convergence and high thermal efficiency for DED powder feeding. [ABSTRACT FROM AUTHOR]

The paper investigates the characteristics of the laser beam percussion micro-drilling (LBPMD) process in aerospace nickel-based superalloy Hastelloy X using microsecond pulses. The quality of the drilled hole is crucial in laser beam micromachining, and selecting appropriate process parameters significantly impacts the hole's quality. The objective is to achieve predefined hole dimensions with minimal taper angles. Additionally, the study focuses on the alteration of pulse width, which is a combination of laser pulse frequency and duty cycle. Laser power (P), duty cycle % (D), focal plane position (FPP), and laser frequency (f) are considered input parameters, while geometric features such as inlet and outlet diameters, hole taper angle, and inlet circularity are examined as process responses. ANOVA is employed to establish significant relationships between process parameters and response variations based on experimental tests. Creating a precise simulation model that accurately accounts for the moving boundary of the target material's receding surface is a crucial and challenging task in formulating the laser heat conduction problem. It is necessary to simultaneously capture the material's dynamic front movement and update the boundary conditions of the laser source. To model the micro-drilled hole with LBPMD, the UMESHMOTION and DFLUX subroutines, along with the arbitrary Lagrangian-Eulerian (ALE) adaptive remesh algorithm in the Abaqus™ software, are utilized. Notably, no previous numerical study has predicted the geometry of micro-drilled holes using this technique. The proposed procedure is validated through the predictions of inlet and outlet hole diameters. Special emphasis is placed on the validation of models. Consequently, the numerical model and statistical model are compared as well as the need to define model applicability. The study demonstrates that all input parameters significantly influence the inlet hole diameter, while the pulse width notably affects the taper angle and circularity. The interaction between high laser frequency and low duty cycle results in reduced pulse duration. Multi-objective optimization is performed to determine the optimal process parameter settings for desired quality characteristics, considering minimum hole taper angle, precise inlet diameter, and maximum inlet circularity of the hole as optimization criteria. The findings show that with the optimized predicted results obtained from the optimal input variables, a composite desirability of 92% can be achieved. [ABSTRACT FROM AUTHOR]

SRON (Netherlands Institute for Space Research) is developing the focal plane assembly (FPA) for Athena X-IFU, whose demonstration model (DM) will use for the first time a time domain multiplexing (TDM)-based readout system for the on-board transition-edge sensors (TES). We report on the characterization activities on a TDM setup provided by NASA goddard space flight center (GSFC) and national institute for standards and technology (NIST) and tested in SRON cryogenic test facilities. The goal of these activities is to study the impact of the longer harness, closer to X-IFU specs, in a different EMI environment and switching from a single-ended to a differential readout scheme. In this contribution we describe the advancement in the debugging of the system in the SRON cryostat, which led to the demonstration of the nominal spectral performance of 2.8 eV at 5.9 keV with 16-row multiplexing, as well as an outlook for the future endeavors for the TDM readout integration on X-IFU's FPA-DM at SRON. [ABSTRACT FROM AUTHOR]

CNES (French Space Agency) is in charge of the development of the X-ray Integral Field Unit (X-IFU) instrument for Athena, the high resolution X-ray spectrometer of the ESA Athena X-ray Observatory. X-IFU will deliver spectra from 0.2 to 12 keV with a spectral resolution in the range of 2.5 eV up to 7 keV on a 5′′ pixels, with a field of view > 4′ equivalent diameter. The main sensor array detection chain is a key part of the instrument, being by far the main contributor to its performance. It involves major partners: NASA GFSC, NIST, SRON, VTT, APC, and IRAP. The cryo-harness interconnecting the Focal Plane Assembly cold interface to the Warm Front End Electronics is under CNES responsibility. The different technical solutions are the loom technology and the shielded twisted pair technology. Characterizations have been performed on breadboards to assess the crosstalk performances for each solution. The results of these analysis are a driver to perform the trade-off between the available cryo-harness technologies. [ABSTRACT FROM AUTHOR]

Expressions are obtained for the position of the maximum Imax of the Fourier transform of a Bessel–Gaussian beam (BGB) and its dependence on the topological charge is substantiated. It is found that Imax depends on the angle of the cone and the parameters of the Gaussian beam. Here, as the cone angle is reduced (and, therefore, the diffraction-free region increases), the distances between the maxima of the intensity distributions in the focal plane of the lens, corresponding to different magnitudes of the topological charge, increase. An expression is found for the position of the energy center of the Fourier transform of the BGB and it is shown that it also depends on the cone angle γ and the size of the Gaussian beam waist w0. As the product γw0 increases, the shift in the energy center of the BGB relative to the radius R of the annular Fourier spectrum in the approximation of geometric optics decreases. These results reveal the impossibility of forming perfect vortices with a BGB. Here the degree of their "imperfection" is determined by the deviation of the maximum of the intensity distribution in the focal plane of the lens on the parameter R which specifies the radius of the ring of the Fourier image of the Bessel beam, which is greater for beams with a larger diffraction-free region. [ABSTRACT FROM AUTHOR]

In this paper, the improved design of an Ice Giants Net Flux Radiometer (IG-NFR), for inclusion as a payload on a future Uranus probe mission, is given. IG-NFR will measure the net radiation flux, in seven spectral bands, each with a 10° Field-Of-View (FOV) and in five viewing angles as a function of altitude. Net flux measurements within spectral filter bands, ranging from solar to far-infrared, will help derive radiative heating and cooling profiles, and will significantly contribute to our understanding of the planet's atmospheric heat balance and structure, tropospheric 3-D flow, and compositions and opacities of the cloud layers. The IG-NFR uses an array of non-imaging Winston cones integrated to a matched thermopile detector Focal Plane Assembly (FPA), with individual bandpass filters and windows, housed in a vacuum micro-vessel. The FPA thermopile detector signals are read out in parallel mode, amplified and processed by a multi-channel digitizer application specific integrated circuit (MCD ASIC) under field programmable gate array (FPGA) control. The vacuum micro-vessel rotates providing chopping between FOV's of upward and downward radiation fluxes. This unique design allows for small net flux measurements in the presence of large ambient fluxes and rapidly changing temperatures during the probe descent to ≥10 bar pressure. [ABSTRACT FROM AUTHOR]

Micro-structured chemical vapor deposition (CVD) diamonds with different geometric features tend to demonstrate outstanding performance and functionality in certain aspects. In this paper, an ablation model for machining micro-structures on the surface of CVD diamond coatings using spray-mist-assisted laser processing was established. Firstly, the principle of spray-mist-assisted laser processing was described, where the water film formed by spray impingement was taken into account for its influence on the laser beam through reflection and absorption, resulting in energy losses, as well as refraction causing focal plane shift. Next, a single groove ablation model was developed based on Gaussian optics and ablation threshold theory. Subsequently, the model validity was verified through laser ablation experiments. Meanwhile, the influences of laser parameters, including laser power, scanning speed, and defocusing distance on the machining characteristics, were discussed. Finally, utilizing raster scanning and incorporating the matrix convolution method, the laser ablation model was further extended. Micro-structures with parabolic-like profiles were achieved, indicating the applicability of this approach in guiding the fabrication of micro-structures with specific contours. [ABSTRACT FROM AUTHOR]

A new approach to the creation of millimeter-wave radio imaging systems is proposed. This approach is based on the use of an array receiver consisting of a densely packed (pixel size of 4 mm) array of planar mixers located in the focal plane of a quasi-optical objective, with application of the frequency-modulated continuous-wave radar technique. It has been demonstrated that the implementation of the heterodyne type of reception makes it possible to increase the distance range of the array radio imaging system up to ~100 m while maintaining the angular resolution at the previous level. [ABSTRACT FROM AUTHOR]

The 14 April 1895 (Mw 6.1, in the area of Ljubljana, Slovenia) earthquake is still not fully understood. The aim of this work is to derive information about its source from the inversion of an updated dataset of intensities (evaluated with EMS-98). This was done via automatic non-linear geophysical inversion KF-NGA, which was performed using a Niching Genetic Algorithm and has been presented in other articles. The distribution of damage caused by this earthquake is not homogeneous and often shows significant intensity differences between neighbouring sites. Statistical analysis of the intensities, epicentral distances and geologic nature of the sites suggests some site effects. Nevertheless, the resulting solution is consistent with regional seismotectonics, i.e. an almost pure dip-slip mechanism: strike 282° ± 5°, dip 38° ± 7°, rake 86° ± 9° (± 180° because of the intrinsic ambiguity of the KF-NGA-inversion). Since the rake angle is close to 90°, there is an almost perfect ambiguity between the two planes of the focal mechanism. Therefore, our solution has a Dinaric direction and could be associated either with a fault plane that dips NE or with one that dips SW. [ABSTRACT FROM AUTHOR]

Self-focusing and self-phase modulation of focused femtosecond laser pulse were studied in bulk fused silica. Depending on pulse energy magnitude, three different regimes were observed in the experiment: (1) linear regime, when the self-focusing effect is insignificant, characterized by linear spectral broadening; (2) transition regime, when the self-focusing effect notably reduces a laser beam spot in a focal plane without considerable nonlinear absorption and beam collapse, characterized by quick increase in spectral broadening due to self-phase modulation; (3) nonlinear regime, filamentation, characterized by near-to- linear spectral broadening due to self-phase modulation. The slope for the linear and nonlinear regimes was the same within the measurement error bars. The numerical simulation, using the ray transfer matrix method, envisioned the self-phase modulation spectral broadening effect in all these regimes. [ABSTRACT FROM AUTHOR]

In this study, we determine the stress release from the 2003 Bam earthquake (Mw 6.6) by applying the stress inversion technique to focal mechanisms of 199 aftershocks. There is no evidence of significant surface faulting that can be used to study the faulting pattern of the Bam fault zone. Therefore, we applied two independent methods for identifying the faulting pattern in this zone: the instability criterion based on the analysis of orientations of nodal planes of focal mechanisms with respect to the regional stress, and the Fry method based on the analysis of spatial clustering of aftershock foci. The results show that the fault associated with the 2003 Bam earthquake is well oriented for shearing under the present-day regional stress. We identified four sets of faults with a close angular relation to the maximum horizontal compression (SHmax) that have been (re)activated. These faults include strike-slip (right lateral and left lateral), thrust, and normal faults that are oriented approximately oblique, perpendicular, and parallel relative to the SHmax, respectively. The direction of the SHmax is N31° E. Based on the results, we propose to apply the instability criterion and the Fry method to seismic data as two valuable and independent techniques in order to constrain the kinematic and active faulting in the area. [ABSTRACT FROM AUTHOR]

In the current work properties of a solar radiance concentrator with Fresnel lens made of Elastosil RT604 silicon made by Wacker have been investigated. The dependence of concentrator focal distance on temperature has been determined. Impact of variation of temperature-dependent concentrator focusing properties on the magnitude of short current of photovoltaic submodule has been determined by direct measurements using solar simulator. Using formalized model of modules based on the studied concentrator and solar cells with three and six p–n-junctions dimensions of a solar image in a wavelength range corresponding to an absorption profile of individual p–n-junctions has been calculated for the temperature range 10–60°C. It has been concluded that in the case of three p–n-junctions the minimum size of solar image at focal plane was 4.7 mm with the distance between the concentrator and solar cell being equal to 106.25 mm, and in the case of six p–n-junctions, the minimum size was 4.8 mm with the distance between concentrator and solar cell being equal to 106.5 mm. [ABSTRACT FROM AUTHOR]

Off-axis parabolic mirrors (OAPMs) are widely used in the THz and mm-wave communities for spectroscopy and imaging applications, as a result of their broadband, low-loss operation and high numerical apertures. However, the aspherical shape of an OAPM creates significant geometric aberrations: these make achieving diffraction-limited performance a challenge, and lower the peak electric field strength in the focal plane. Here, we quantify the impact of geometric aberrations on the performance of the most widely used spectrometer designs, by using ray tracing and physical optics calculations to investigate whether diffraction-limited performance can be achieved in both the sample and the detector plane. We identify simple rules, based on marginal ray propagation, that allow spectrometers to be designed that are more robust to misalignment errors, and which have minimal aberrations for THz beams. For a given source, this allows the design of optical paths that give the smallest THz beam focal spot, with the highest THz electric field strength possible. This is desirable for improved THz imaging, for better signal-to-noise ratios in linear THz spectroscopy and optical-pump THz-probe spectroscopy, and to achieve higher electric field strengths in non-linear THz spectroscopy. [ABSTRACT FROM AUTHOR]

The dipole characteristics of Frenkel excitons and charge-transfer excitons between donor and acceptor molecules in organic heterostructures such as exciplexes are important in organic photonics and optoelectronics. For the bilayer of the organic donor 4,4′,4′′-tris[(3-methylphenyl)phenylamino]triphenylamine and acceptor 2,4,6-tris(biphenyl-3-yl)-1,3,5-triazine molecules, the exciplexes form aligned dipoles perpendicular to the Frenkel excitons, as observed in back focal plane photoluminescence images. The angular chromism of exciplexes observed in the 100 meV range indicates possible delocalization and angle-sensing photonic applications. The blue shift of the peak position and increase in the linewidth of photoluminescene spectra with increasing excitation power are caused by the repulsive aligned exciplex dipole moments with a long lifetime (4.65 μs). Electroluminescence spectra of the exciplex from organic light-emitting diodes using the bilayer are blue-shifted with increasing bias, suggesting unidirectional alignment of the exciplex dipole moments. The observation of exciplex dipole moment alignments across molecular interfaces can facilitate the controlled coupling of exciton species and increase efficiency of organic light-emitting diodes. The directional features of dipole moments of Frenkel excitons and exciplexes are important for optoelectronic applications. Here, the authors study photo- and electro-luminescence emissions of organic heterostructures and observe angular chromism of exciplexes, indicating possible delocalization. [ABSTRACT FROM AUTHOR]

Depth information is useful in many image processing applications. However, since taking a picture is a process of projection of a 3D scene onto a 2D imaging sensor, the depth information is embedded in the image. Extracting the depth information from the image is a challenging task. A guiding principle is that the level of blurriness due to defocus is related to the distance between the object and the focal plane. Based on this principle and the widely used assumption that Gaussian blur is a good model for defocus blur, we formulate the problem of estimating the spatially varying defocus blurriness as a Gaussian blur classification problem. We solve the problem by training a deep neural network to classify image patches into one of the 20 levels of blurriness. We have created a dataset of more than 500,000 image patches of size 32 × 32 which does not require human labelling. The dataset is used to train and test several well-known network models. We find that MobileNetV2 is suitable for this application due to its low memory requirement and high accuracy. The trained model is used to determine the patch blurriness which is then refined by applying an iterative weighted guided filter. The result is a defocus map that carries the information of the degree of blurriness for each pixel. We compare the proposed method with state-of-the-art techniques and we demonstrate its successful applications in adaptive image enhancement and defocus magnification limited to images that present a clear distinction between defocus levels. [ABSTRACT FROM AUTHOR]

Seismic swarms of low magnitude earthquakes occur frequently in the Calabrian Arc. During the last few years, several earthquakes of magnitude up to ML4.4 occurred both on land and offshore near the coast of Calabria. Some of them were followed by a sequence of tens to hundreds of smaller, well-clustered earthquakes that occurred during the following weeks or months. In other cases, swarms of low-magnitude earthquakes occur without a classical mainshock-aftershock evolution. In this work, we selected swarms that were well recorded by a high number of seismic stations to perform a detailed analysis consisting of the determination of the relative location and focal mechanism for as many earthquakes as possible. In some cases, the relative location allows to recognize the seismogenic fault and to distinguish the fault plane from the auxiliary plane of the focal mechanism solution. In other cases, the relative location unravels a small cloud of events that is not compatible with a unique fault plane, suggesting the occurrence of the swarm in highly fractured seismogenic volume. The relative hypocenter positions allow to estimate the size of the seismogenic volume, which is very small in most of the cases, often less than 1 km3. However, its extension is greater than the size computed for the mainshock rupture in many cases. The most common source mechanism is of normal type, but strike-slip and reverse kinematics are also found, in particular for swarms located offshore and near the coast. The temporal distribution of events does not show any evident migration of the sources, thus suggesting that the driving mechanism is not related with aseismic phenomena like fluid diffusion and stress waves. [ABSTRACT FROM AUTHOR]

Spontaneous parametric down-conversion (SPDC) is a widely used process to prepare entangled photon pairs. In SPDC, a second-order nonlinear crystal is pumped by a coherent laser beam to generate photon pairs. The photon pairs are usually detected by single-mode fibers (SMF), where only photons in a Gaussian mode can be collected. The collection modes possess typical Gaussian parameters, namely a beam waist and a focal plane position. The collection efficiency of photons highly depends on the choice of both parameters. The exact focal plane position of the pump beam relative to those of the detection modes is difficult to determine in a real experiment. Usually, theoretical and experimental studies assume that the focal plane positions of the pump and the generated beams are positioned in the center of the crystal. The displacement of beam focal planes can lead to deviations from expected results and the coupling efficiency into SMF can decrease. In this study, we theoretically examine variable positions of focal planes in the Laguerre–Gaussian basis, a popular experimental modal decomposition of the spatial biphoton state. We explore how the choice of focal plane positions affects the spatial and temporal properties and the purity of the photon pairs. We present SPDC setups where precise knowledge of the focal plane position is essential and scenarios where focal plane displacements have negligible impact on experimental outcomes. [ABSTRACT FROM AUTHOR]

Earthquake focal mechanisms provide critical in-situ insights about the subsurface faulting geometry and stress state. For frequent small earthquakes (magnitude< 3.5), their focal mechanisms are routinely determined using first-arrival polarities picked on the vertical component of seismometers. Nevertheless, their quality is usually limited by the azimuthal coverage of the local seismic network. The emerging distributed acoustic sensing (DAS) technology, which can convert pre-existing telecommunication cables into arrays of strain/strain-rate meters, can potentially fill the azimuthal gap and enhance constraints on the nodal plane orientation through its long sensing range and dense spatial sampling. However, determining first-arrival polarities on DAS is challenging due to its single-component sensing and low signal-to-noise ratio for direct body waves. Here, we present a data-driven method that measures P-wave polarities on a DAS array based on cross-correlations between earthquake pairs. We validate the inferred polarities using the regional network catalog on two DAS arrays, deployed in California and each comprising ~ 5000 channels. We demonstrate that a joint focal mechanism inversion combining conventional and DAS polarity picks improves the accuracy and reduces the uncertainty in the focal plane orientation. Our results highlight the significant potential of integrating DAS with conventional networks for investigating high-resolution earthquake source mechanisms. Determining earthquake faulting orientation is essential for understanding earthquake-stress interactions. Here, the authors present a technique that leverages telecom fiber optic cables to improve the estimation of this fundamental parameter. [ABSTRACT FROM AUTHOR]

The Einstein Probe (EP) satellite is designed for X-ray time-domain astronomy. The Follow-up X-ray Telescope (FXT) is one of the scientific payloads onboard EP. It will mainly be used for the follow-up X-ray observation, and it will also be used for the sky survey and Target of Opportunity (ToO) observation. The focal plane detector of FXT provided by the Max Planck Institute for Extraterrestrial Physics (MPE) adopts a PNCCD sensor. For detector cooling, a helium pulse tube refrigerator is used, provided by the Technical Institute of Physics and Chemistry (TIPC), Chinese Academy of Sciences (CAS), to keep the detector working at a temperature of −90 ± 0.5 °C. The PNCCD driving and data acquisition electronics are developed by the Institute of High Energy Physics (IHEP), CAS. To observe different celestial sources, we designed six filter wheel positions and three scientific operating modes for the PNCCD detector: the full-frame mode, the partial-window mode, and the timing mode. In the full-frame mode, the system frame rate is 20 frame/s and the energy resolution of the whole system reaches 92 eV @ 1.49 keV (FWHM). The frame rate of partial-window mode is 500 frame/s. In the timing mode, the time resolution is about 94 μs. This paper mainly introduces the design and test results of the focal plane camera. [ABSTRACT FROM AUTHOR]

The Einstein Probe (EP) mission is a science mission designed for the time domain astronomy, which is approved by the Chinese Academy of Sciences (CAS) in 2017 and is to be launched in 2023 with a duration time of more than 3 years. The Follow-up X-ray Telescope (FXT) is an important payload onboard EP, which employs the Wolter I focusing mirror as the X-ray collection unit and the PNCCD as the focal plane detector. The Phase C study has been finished in 2021. During the Phase C, the structural and thermal model (STM) of the mirror assembly of FXT, provided by the European Space Agency (ESA), a mirror assembly developed by the Institute of High Energy Physics (IHEP), a qualification model (QM) PNCCD and other components, are integrated and tested in IHEP. All optical performances meet the goal requirement of EP, such as the field of view of 60 arcmins, the angular resolution of less than 30 arcsec HEW on-axis, and the focal length of ab. 1600 mm. After that, the FXT is assembled, integrated, and tested on the EP satellite platform. Furthermore, these performances are not changed after the mechanical and thermal tests on the spacecraft platform. [ABSTRACT FROM AUTHOR]

MUSCAT is a new large-format 1.1 mm continuum camera for local and extra-galactic astronomy currently being installed at the 50 m Large Millimetre Telescope Alfonso Serrano, LMT. The focal plane is populated with 1458 feedhorn coupled Aluminium LEKIDs, cooled to 130 mk, and read out with 6 frequency division multiplexed RF readout chains, each with a 500 MHz bandwidth. The nominal mux ratio is ∼ 250 resonators per chain with an average spacing of 2 MHz between resonators. In each RF chain, the multiplexed waveform generation/decomposition is performed with the BLAST-TNG firmware on a ROACH2 FPGA board with a MUSIC DAC/ADC. The quadrature modulated IF signals are mixed to and from the LEKID readout band on a custom card that houses IQ mixers, a programmable synthesizer, and additional programmable input and output gain control and filtering. Within the cryostat, the RF signals are attenuated prior to reaching the focal plane array and then amplified at 4K. A novel software system controls all the programmable hardware and handles instructions from the LMT instrument control system to record and store observation data, as well as performing automated resonator retuning and providing results of quick look analysis to the telescope operators. In this paper, we present the detailed design and in-lab performance of the cryogenic and room temperature electronics, and the software control system. [ABSTRACT FROM AUTHOR]

The BICEP/Keck series of experiments target the cosmic microwave background at degree-scale resolution from the South Pole. Over the next few years, the "Stage-3" BICEP Array (BA) telescope will improve the program's frequency coverage and sensitivity to primordial B-mode polarization by an order of magnitude. The first receiver in the array, BA1, began observing at 30/40 GHz in early 2020. The next two receivers, BA2 and BA3, are currently being assembled and will map the southern sky at frequencies ranging from 95 to 150 GHz. Common to all BA receivers is a refractive, on-axis, cryogenic optical design that focuses microwave radiation onto a focal plane populated with antenna-coupled bolometers. High-performance antireflective coatings up to 760 mm in aperture are needed for each element in the optical chain, and must withstand repeated thermal cycles down to 4 K. Here, we present the design and fabrication of the 30/40 GHz anti-reflection coatings for the recently deployed BA1 receiver, with indices matched to its various polyethylene, nylon and alumina optical components. We describe an epoxy coating technique designed for alumina optics, which achieves better than 80% transmission at room temperature. For polyethylene optical elements, we present a new heat-compression approach that allows low-density polytetrafluoroethylene AR layers to reach sub-percent reflected power. We describe the planned use of these methods for the next BA cryostats, which may inform technological choices for future small-aperture telescopes of the CMB-S4 experiment. [ABSTRACT FROM AUTHOR]

Superconducting On-chip Fourier Transform Spectrometers (SOFTS) are broadband, ultra-compact and electronic interferometers. SOFTS will enable kilo-pixel spectro-imaging focal planes, enhancing sub-millimeter astrophysics and cosmology. Particular applications include cluster astrophysics, cosmic microwave background (CMB) science, and line intensity mapping. This article details the development, design and bench-marking of radio frequency (RF) on-chip architecture of SOFTS for Ka and W-bands. [ABSTRACT FROM AUTHOR]

A modular cryogenic cross-disperser MOBIUS for the Large Binocular Telescope (LBT) is being developed to produce a simultaneous zJHK spectrum with a single LUCI, the LBT Utility Cameras in the Infrared. Its compact and exchangeable optical design fit within the existing focal plane mask frame of the LUCI spectrograph without any other hardware modifications. This unique deployable system enables a rapid acquisition of data over a wide wavelength range to better understand the unknown objects in the universe. [ABSTRACT FROM AUTHOR]

A 2D model for the annealing process after ion implantation in HgCdTe was established. The 2D model was based on the diffusion equations of Hg vacancy and interstitial. Generation and annihilation of the Hg vacancy and interstitial were considered. The coupled diffusion equations combined with the boundary equation were solved simultaneously. Annealing temperature and annealing time dependence experiments were carried out to determine the key parameter and prove the effectiveness of the 2D model. This work provides an efficient 2D model of the annealing process in n-on-p HgCdTe, which makes the junction design of HgCdTe less costly and more accurate and gives fundamental guidance to the fabrication of small-pitch focal planes. [ABSTRACT FROM AUTHOR]

Two-photon stereolithography (TPS) is widely used for the fabrication of various three–dimensional (3D) structures with sub-micron fabrication resolution in a single fabrication process. However, TPS is unsuitable for microstructures with fine-hole patterns. The laser ablation process can be easily drilled, or made holes in various materials. However, in the case of laser ablation, the focal plane of the laser is fixed, which is limited to the processing plane. In this study, a multidirectional ablation process is studied to apply laser ablation to various processing planes of a 3D microstructure fabricated by the TPS process. A 3D hybrid fabrication process with the advantages of both TPS and laser ablation is expected to improve the fabrication efficiency. The 3D hybrid process is proposed based on a single laser source. The microstructure is fabricated using TPS, and the multi-directional ablation process creates a hole in the lateral side of the 3D microstructure. To develop the multidirectional ablation process, the reflecting mirror system should be designed to adaptably rotate the laser focal plane and guide the laser path for the target process plane. Through various examples, we demonstrate the ability of the multi-directional ablation process with various examples. [ABSTRACT FROM AUTHOR]

Biochip-based research is currently evolving into a three-dimensional and large-scale basis similar to the in vivo microenvironment. For the long-term live and high-resolution imaging in these specimens, nonlinear microscopy capable of label-free and multiscale imaging is becoming increasingly important. Combination with non-destructive contrast imaging will be useful for effectively locating regions of interest (ROI) in large specimens and consequently minimizing photodamage. In this study, a label-free photothermal optical coherence microscopy (OCM) serves as a new approach to locate the desired ROI within biological samples which are under investigation by multiphoton microscopy (MPM). The weak photothermal perturbation in sample by the MPM laser with reduced power was detected at the endogenous photothermal particles within the ROI using the highly sensitive phase-differentiated photothermal (PD–PT) OCM. By monitoring the temporal change of the photothermal response signal of the PD–PT OCM, the hotspot generated within the sample focused by the MPM laser was located on the ROI. Combined with automated sample movement in the x–y axis, the focal plane of MPM could be effectively navigated to the desired portion of a volumetric sample for high-resolution targeted MPM imaging. We demonstrated the feasibility of the proposed method in second harmonic generation microscopy using two phantom samples and a biological sample, a fixed insect on microscope slide, with dimensions of 4 mm wide, 4 mm long, and 1 mm thick. [ABSTRACT FROM AUTHOR]

In microscale particle velocimetry, the spatial resolution of velocity measurements along the optical axis is often degraded by signal from tracer particles outside the focal plane. Structured illumination microscopy particle tracking velocimetry (SIM PTV) can eliminate most of this out-of-focus signal by using illumination with a non-zero spatial frequency to preferentially illuminate the in-focus particles. Two such (raw) images can then be combined to eliminate the background signal and demodulate the image. The objective of this study was to quantify and optimize the spatial and temporal resolution of SIM PTV based upon Poiseuille flow in a microchannel at Reynolds numbers Re ≈ 0.02. The axial spatial resolution, estimated for this known velocity profile from the standard deviation of the velocity measurements, is improved by at least a factor of 2 compared with the results for a uniformly illuminated flow. This axial spatial resolution is in good agreement with that given by the point spread function of the imaging system derived by Neil et al. (Neil et al., Opt Lett 22:1905–1907, 1997). The spatial frequency of the illumination that optimizes the spatial resolution is a function of the scattering area of the tracer particles. Interestingly, increasing the number of raw images does not appear to improve the axial resolution. Finally, the temporal resolution of SIM PTV is estimated based upon both image and velocity acquisition times. [ABSTRACT FROM AUTHOR]

This paper presents a design and synthesizing preprocess of silicon-integrated focal plane plasmonic switch array (FPPSA) to sensitize the beam steering sensor functions in the wider field-of-view (FoV). Initially, FPPSA is formulated with the base plasmonic beam steering theory and then we designed a structure with a 24 × 24 FPP switch array using 480 nm wider plasmonic reactive beam steering which is integrated to accomplish a phase noise of less than 0.005 dB. Furthermore, the proposed sensor is synthesized with electromechanical plasmonic unbuffered phase switches with absorption of greater than 2.66 dB/m, error estimation of 0.355 dB/m, power group index of 5.08–8.058 and the coupling coefficient of 0.22–0.856, beam divergence 0.045° × 0. 45° behavioral analysis has been done. The numerical result shows that conduction distance with the potentials 0.366 eV and 0.199 eV by the power of 20 nW are used to achieve near and far FoV of 45° × 45°−120° × 120 °. The comparative study is carried out with the existing methods (thermo optics, electro-optics, MEMS sensor beam steering sensor). Finally, the proposed design is done by exploring the Ansys Lumerical simulator. The synthesizing results received the confidence of FoV to obtain good stability in blind zone suppressed by beam steering for autonomous navigation. [ABSTRACT FROM AUTHOR]

In myopia, the eye grows too long, and the image projected on the retina is poorly focused when subjects look at a distance. While the retina normally controls eye growth by visual processing, it seems to give up during myopia development. But what has changed? To determine whether the sharp image is in front or behind the retinal plane, a comparison of image sharpness in red and blue would provide a reliable cue because focal planes are about 1.3 D apart due to longitudinal chromatic aberration (LCA). However, up to now, it could not be demonstrated that the retina does, in fact, such a comparison. We used a new approach: movies were digitally filtered in real time to present either the blue channel of the RGB color format unfiltered while green and red were blurred ("blue in focus"), or the red channel was unfiltered while green and blue were blurred ("red in focus") accordingly to the human LCA function. Here we show that, even though filtered movies looked similar, eyes became significantly shorter when the movie was sharp in the red plane but became longer when it was presented sharp in the blue plane. Strikingly, the eyes of young subjects who were already myopic did not respond at all—showing that their retina could no longer decode the sign of defocus based on LCA. Our findings resolve a long-standing question as to how the human retina detects the sign of defocus. It also suggests a new non-invasive strategy to inhibit early myopia development: keeping the red image plane on a computer screen sharp but low pass filtering the blue. [ABSTRACT FROM AUTHOR]

To date, the feasibility of super-resolution microscopy for imaging live and thick samples is still limited. Stimulated emission depletion (STED) microscopy requires high-intensity illumination to achieve sub-diffraction resolution, potentially introducing photodamage to live specimens. Moreover, the out-of-focus background may degrade the signal stemming from the focal plane. Here, we propose a new method to mitigate these limitations without drawbacks. First, we enhance a STED microscope with a detector array, enabling image scanning microscopy (ISM). Therefore, we implement STED-ISM, a method that exploits the working principle of ISM to reduce the depletion intensity and achieve a target resolution. Later, we develop Focus-ISM, a strategy to improve the optical sectioning and remove the background of any ISM-based imaging technique, with or without a STED beam. The proposed approach requires minimal architectural changes to a conventional microscope but provides substantial advantages for live and thick sample imaging. Super-resolution microscopy techniques can be challenging for live cells and thick samples. Here, the authors propose a method to reduce beam intensity and remove out-of-focus fluorescence background in image-scanning microscopy (ISM) and its combination with stimulated emission depletion (STED). [ABSTRACT FROM AUTHOR]

Light-field cameras allow the acquisition of both the spatial and angular components of the light-field. The conventional way to perform such acquisitions leads to a strong spatio-angular resolution limitation but correlation-enabled plenoptic cameras have been introduced recently that relax this constraint. Here we use a computational version of this concept to acquire realistic light-fields images using a commercial DSLR Camera lens as an imaging system. By placing the image sensor in the focal plane of a lens, within the camera we ensure the acquisition of pure angular components together with the spatial information. We perform an acquisition presenting a high spatio-angular rays resolution obtained through a trade off of the temporal resolution. The acquisition reported is photo-realistic and the acquisition of diffraction limited features is observed with the setup. Finally, we demonstrate the refocusing abilities of the camera. [ABSTRACT FROM AUTHOR]

A survey of nuclear structure results obtained along α -decay chains stemming from isotopes of element 114, Fl, and element 115, Mc, is presented. Measures taken to ensure a reliable hand-over of nuclear spectroscopy output to nuclear structure theory are outlined. Possible links between decay chains starting from element 117, Ts, and element 115, Mc, are commented on. The experiments were conducted with the TASISpec set-up placed in the focal plane of the TASCA separator at the GSI Helmholtzzentrum für Schwerionenforschung GmbH in Darmstadt, Germany. Plans to improve the decay-spectroscopy set-up towards future superheavy endeavours are described. [ABSTRACT FROM AUTHOR]

We report on the kinetic inductance detector (KID) array focal plane assembly design for the Terahertz Intensity Mapper (TIM). Each of the 2 arrays consists of 4 wafer-sized dies (quadrants), and the overall assembly must satisfy thermal and mechanical requirements, while maintaining high optical efficiency and a suitable electromagnetic environment for the KIDs. In particular, our design manages to strictly maintain a 50 μ m air gap between the array and the horn block. We have prototyped and are now testing a sub-scale assembly which houses a single quadrant for characterization before integration into the full array. The initial test result shows a >95% yield, indicating a good performance of our TIM detector packaging design. [ABSTRACT FROM AUTHOR]

The MIllimetric Sardinia radio Telescope Receiver based on Array of Lumped elements KIDs, MISTRAL, is a cryogenic W-band (77–103 GH) LEKID camera which will be integrated at the Gregorian focus of the 64 m aperture Sardinia Radio Telescope, in Italy, in Autumn 2022. This instrument, thanks to its high angular resolution ( ∼ 13 arcsec ) and the wide instantaneous field of view ( ∼ 4 arcmin ), will allow continuum surveys of the mm-wave sky with a variety of scientific targets, spanning from extragalactic astrophysics to solar system science. In this contribution, we will describe the design of the MISTRAL camera, with a particular focus on the optimisation and test of a prototype of the focal plane. [ABSTRACT FROM AUTHOR]

We measured the vibration of a prototype superconducting magnetic bearing (SMB) operating at liquid nitrogen temperature. This prototype system was designed as a breadboard model for LiteBIRD low-frequency telescope (LFT) polarization modulator unit. We set an upper limit of the vibration amplitude at 36 μ m at the rotational synchronous frequency. During the rotation, the amplitude of the magnetic field produced varies. From this setup, we compute the static and AC amplitude of the magnetic fields produced by the SMB magnet at the location of the LFT focal plane as 0.24 and 3 × 10 - 5 G, respectively. From the AC amplitude, we compute TES critical temperature variation of 7 × 10 - 8 K and fractional change of the SQUID flux is δ Φ / Φ 0 | ac = 3.1 × 10 - 5 . The mechanical vibration can be also estimated to be 3.6 × 10 - 2 N at the rotation mechanism location. [ABSTRACT FROM AUTHOR]

The far-infrared (FIR) band is uniquely suited to study the physical conditions in the interstellar medium and star formation out to the highest redshifts. Robust, high sensitivity detector arrays that operate over the entire FIR regime with up to several 104 pixels, large focal plane filling factors and compatibility with low noise detector designs and low cosmic ray cross sections, are required for future (F)IR missions, such as Origins. The arrays could consist of smaller sub-arrays, since they can be tiled. The GSFC-designed Backshort Under Grid (BUG) array architecture and its precursor architectures have been fielded in several FIR cameras, including GISMO at the IRAM 30 m telescope (the array used in this instrument was strictly speaking a precursor to the final BUG array) and HAWC + on SOFIA. The BUG array used in the latter instruments has an integrated termination board and SQUID readout multiplexer. The array was fabricated in collaboration between NASA/GSFC and NIST and meets these requirements. However, the BUG fabrication has many low throughput processing steps, with the consequence of long production times and sub-optimal yields. To meet the requirements for robustness and production efficiency for future arrays, we have developed, and by now partially demonstrated, a new architecture to provide the superconducting connection of transition edge sensor detectors to the readout multiplexers or readout boards behind the array. This approach will allow us to reach the goal to produce reliable, large low noise detector arrays for future space-based and suborbital instrumentation. [ABSTRACT FROM AUTHOR]

The Summertime Line Intensity Mapper (SLIM) is a mm-wave line-intensity mapping (mm-LIM) experiment for the South Pole Telescope (SPT). The goal of SPT-SLIM is to serve as a technical and scientific pathfinder for the demonstration of the suitability and in-field performance of multi-pixel superconducting filterbank spectrometers for future mm-LIM experiments. Scheduled to deploy in the 2023-24 austral summer, the SPT-SLIM focal plane will include 18 dual-polarisation pixels, each coupled to an R = λ / Δ λ = 300 thin-film microstrip filterbank spectrometer that spans the 2 mm atmospheric window (120–180 GHz). Each individual spectral channel feeds a microstrip-coupled lumped-element kinetic inductance detector, which provides the highly multiplexed readout for the 10k detectors needed for SPT-SLIM. Here, we present an overview of the preliminary design of key aspects of the SPT-SLIM focal plane array, a description of the detector architecture and predicted performance, and initial test results that will be used to inform the final design of the SPT-SLIM spectrometer array. [ABSTRACT FROM AUTHOR]