Surface wave control for large arrays of microwave kinetic inductance detectors

Large ultra-sensitive detector arrays are needed for present and future observatories for far infra-red, submillimeter wave (THz), and millimeter wave astronomy. With increasing array size, it is increasingly important to control stray radiation inside the detector chips themselves, the surface wave. We demonstrate this effect with focal plane arrays of 880 lens-antenna coupled Microwave Kinetic Inductance Detectors (MKIDs). Presented here are near field measurements of the MKID optical response versus the position on the array of a reimaged optical source. We demonstrate that the optical response of a detector in these arrays saturates off-pixel at the $\sim-30$ dB level compared to the peak pixel response. The result is that the power detected from a point source at the pixel position is almost identical to the stray response integrated over the chip area. With such a contribution, it would be impossible to measure extended sources, while the point source sensitivity is degraded due to an increase of the stray loading. However, we show that by incorporating an on-chip stray light absorber, the surface wave contribution is reduced by a factor $>$10. With the on-chip stray light absorber the point source response is close to simulations down to the $\sim-35$ dB level, the simulation based on an ideal Gaussian illumination of the optics. In addition, as a crosscheck we show that the extended source response of a single pixel in the array with the absorbing grid is in agreement with the integral of the point source measurements.Comment: accepted for publication in IEEE Transactions on Terahertz Science and Technolog

Social intuition: behavioral and neurobiological considerations

Social intuition is instrumental in bringing about successful human interactions, yet its behavioral and neural underpinnings are still poorly understood. We focus in this article on the automatic, involuntary, nature of social intuition, rather than on higher-level cognitive and explicit Theory-of-Mind processes (which contribute to rendering social intuition meaningful in real-life situations). We argue that social-affective implicit learning plays a crucial role in establishing automatic social intuition. These implicit learning processes involve associations between the perception of other’s bodily articulations, concurrent events, and the consequences or outcomes in terms of subsequent actions, affective valences and visceral states. The traditional non-social implicit learning paradigms do not allow one to draw conclusions about the role of implicit learning processes in social intuition, as they lack these vital characteristics typically associated with human actions. We introduce a new implicit learning paradigm, which aims to fill these gaps. It targets agile, rapid, social-affective learning processes, involving cue contingencies with a relatively simple structure, unlike the very complex structures that underpin the traditional tasks. The paradigm features matching social and non-social versions, allowing direct comparison. Preliminary data suggest equal performance of TD (typically-developed) and ASC (autism spectrum conditions) groups on the non-social version, but impaired implicit learning in ASC on the social version. We hypothesize that this reflects an anomalous use of implicitly learned affective information in ASC when judging other people. We further argue that the mirror neuron mechanism (MNM), which is part of the Action Observation Network, forms an integral part of the neural substrate for social intuition. In particular as there are indications that the MNM supports action anticipation, and that implicitly learned information can trigger MNM activation, which both seem vital to a social intuition ability. The insights that can be derived from comparing the performances of TD and ASC individuals on (non)social implicit learning tasks, and the implications for the role of MNM activation, are discussed

Full characterization and analysis of a terahertz heterodyne receiver based on a NbN hot electron bolometer

We present a complete experimental characterization of a quasioptical twin-slot antenna coupled small area (1.0×0.15 µm^2) NbN hot electron bolometer (HEB) mixer compatible with currently available solid state tunable local oscillator (LO) sources. The required LO power absorbed in the HEB is analyzed in detail and equals only 25 nW. Due to the small HEB volume and wide antenna bandwidth, an unwanted direct detection effect is observed which decreases the apparent sensitivity. Correcting for this effect results in a receiver noise temperature of 700 K at 1.46 THz. The intermediate frequency (IF) gain bandwidth is 2.3 GHz and the IF noise bandwidth is 4 GHz. The single channel receiver stability is limited to 0.2–0.3 s in a 50 MHz bandwidth

Complex Beam Mapping and Fourier Optics Analysis of a Wide-Field Microwave Kinetic Inductance Detector Camera

For astronomical instruments, accurate knowledge of the optical pointing and coupling are essential to characterize the alignment and performance of (sub-)systems prior to integration and deployment. Ideally, this requires the phase response of the optical system, which for direct (phase insensitive) detectors was not previously accessible. Here we show development of the phase sensitive complex beam pattern technique using a dual optical source heterodyne technique for a large field of view Microwave Kinetic Inductance Detector camera at 350 GHz. We show here how you can analyze the measured data with Fourier optics, which allows integration into a telescope model to calculate the on sky beam pattern and telescope aperture efficiency prior to deployment at a telescope.Comment: This is a post-peer-review, pre-copy edit version of an article published in Journal of Low Temperature Physics. The final authenticated version is available onlin

Applying Energy Absorption Interferometry to THz direct detectors using photomixers

Detector requirements for far infrared astronomy generally result in devices which exhibit a few-moded response to incident radiation. The sensitivity and spatial form of the individual modes to which such a detector is sensitive can be determined with knowledge of the complex valued cross-spectral density of the system, which we label the detector response function (DRF). A matrix representing the discretized cross-spectral density can be measured from the complex amplitudes of interference fringes generated by two identical sources as they are independently scanned through the field of view. We provide experimental verification of this technique using monochromatic THz beams generated by photomixers in which the relative phase is varied with fiber stretchers. We use this system to characterize the modal response of a single pixel from an array of microwave kinetic inductance detectors (MKIDs).Comment: in IEEE Transactions on Terahertz Science and Technology. 202

Occupational therapy for community dwelling elderly people: a systematic review

OBJECTIVE: Occupational therapy might play an important role in maintaining independent living for community dwelling elderly people. The aim of this systematic review is to determine whether occupational therapy improves outcome for people who are >/=60 years and are living independently. METHODS: An extensive search in MEDLINE, CINAHL, EMBASE, AMED and SCISEARCH until July 2002 was performed. Studies with controlled and uncontrolled designs were included. Six intervention categories were distinguished and individually analysed using a best-evidence synthesis, based on the type of design, the methodological quality, type of outcome measures and statistical significance of findings. RESULTS: 17 studies were included, ten of which were randomised clinical trials. Six randomised clinical trials had a high methodological quality. Strong evidence is present for the efficacy of advising on assistive devices as part of a home hazards assessment on functional ability. There is some evidence for the efficacy of training of skills combined with a home hazard assessment in decreasing the incidence of falls in elderly people at high risk of falling. Some evidence is available for the efficacy of comprehensive occupational therapy on functional ability, social participation and quality of life. Insufficient evidence is present for the efficacy of counselling the primary caregiver of dementia patients about maintaining the patient's functional abilities. CONCLUSION: This review shows that occupational therapy interventions for community dwelling elderly people results in positive outcomes. Future research in the efficacy of occupational therapy in elderly patient groups such as people with dementia is recommended. Furthermore, research into tailoring interventions to the needs of elderly patients is recommended. (aut.ref.

Public Engagement in Energy Research

Public Engagement in Research is a key element in "Responsible Research and Innovation"; a cross-cutting issue in current European research funding. Public engagement can advance energy R&D, by delivering results that are more in-line with society's views and demands; and collaboration also unlocks societal skills and knowledge. This paper structures the ways to look at engagement, and gives some pointers on how to implement it in energy R&D, with various levels of intensity. The publics to engage with can be citizens, future users, affected persons, but also organisations that represent them. We have selected methods and tools that showcase a broad range of types of engagement that have been applied in The Netherlands or the UK. The cases are grouped based on the role of the researcher in the engagement process. These roles relate to discussing with, consulting, involving, collaborating with and supporting the various publics. This study shows that there is a diversity of tools and methods already available-open to variation, combinations and further development- that facilitate the participation of society in energy research. Not only for democratic reasons, but also for instrumental benefits in creating innovations to help solve the Grand Societal Challenge of the energy transition