Tuning of Kilopixel Transition Edge Sensor Bolometer Arrays with a Digital Frequency Multiplexed Readout System

A digital frequency multiplexing (DfMUX) system has been developed and used to tune large arrays of transition edge sensor (TES) bolometers read out with SQUID arrays for mm-wavelength cosmology telescopes. The DfMUX system multiplexes the input bias voltages and output currents for several bolometers on a single set of cryogenic wires. Multiplexing reduces the heat load on the camera's sub-Kelvin cryogenic detector stage. In this paper we describe the algorithms and software used to set up and optimize the operation of the bolometric camera. The algorithms are implemented on soft processors embedded within FPGA devices operating on each backend readout board. The result is a fully parallelized implementation for which the setup time is independent of the array size.Comment: 5 pages, 4 figure

Software systems for operation, control, and monitoring of the EBEX instrument

We present the hardware and software systems implementing autonomous operation, distributed real-time monitoring, and control for the EBEX instrument. EBEX is a NASA-funded balloon-borne microwave polarimeter designed for a 14 day Antarctic flight that circumnavigates the pole. To meet its science goals the EBEX instrument autonomously executes several tasks in parallel: it collects attitude data and maintains pointing control in order to adhere to an observing schedule; tunes and operates up to 1920 TES bolometers and 120 SQUID amplifiers controlled by as many as 30 embedded computers; coordinates and dispatches jobs across an onboard computer network to manage this detector readout system; logs over 3~GiB/hour of science and housekeeping data to an onboard disk storage array; responds to a variety of commands and exogenous events; and downlinks multiple heterogeneous data streams representing a selected subset of the total logged data. Most of the systems implementing these functions have been tested during a recent engineering flight of the payload, and have proven to meet the target requirements. The EBEX ground segment couples uplink and downlink hardware to a client-server software stack, enabling real-time monitoring and command responsibility to be distributed across the public internet or other standard computer networks. Using the emerging dirfile standard as a uniform intermediate data format, a variety of front end programs provide access to different components and views of the downlinked data products. This distributed architecture was demonstrated operating across multiple widely dispersed sites prior to and during the EBEX engineering flight.Comment: 11 pages, to appear in Proceedings of SPIE Astronomical Telescopes and Instrumentation 2010; adjusted metadata for arXiv submissio

The association between global cognitive function and walking capacity in individuals with broad ranges of cognitive and physical function: Are there sex differences?

IntroductionCognitive function is known to be associated with physical function, where greater walking capacity has been shown to have moderate to strong correlations with global cognitive function and other various domains of cognition in older adults with and without chronic conditions. Biological sex may moderate the relationship between cognitive and physical function, but whether sex differences exist in this association has not been examined in an aging population. The purpose of this study was to examine the associations between global cognitive function (Montreal Cognitive Assessment; MoCA), walking capacity (6-Minute Walk Test distance; 6 MWT) and sex in an aging population with broad ranges of cognitive and physical function.MethodsParticipants were assessed for global cognitive function (MoCA) and walking capacity (6 MWT). Multivariable regression analyses were performed to examine the interaction of sex in the association between MoCA and 6 MWT. First, we presented the unadjusted model (Model 1), then the model adjusted for age, history of stroke, and height (Model 2). To determine if there were sex-based differences in the association between global cognitive function and walking capacity, we included sex and an interaction term between sex*6 MWT distance in Models 3 and 4.ResultsTwenty-three females and 36 males were included in the multivariable regression analyses, respectively. Our sample represented broad ranges of cognitive and physical function levels, where MoCA scores ranged from 13 to 30, and 6 MWT distances from 203 to 750 m. 6 MWT distance was associated with MoCA in models unadjusted (R2 = 0.17; F(1,56) = 11.4; p < 0.01) and adjusted for age, stroke history, and height (R2 = 0.20; F(4,53) = 3.2; p = 0.02). No interaction with sex was found, but a main effect of sex was observed (R2 = 0.26; F(5,21) = 3.72; p = 0.03). When adjusting for age, height and history of stroke, males MoCA scores were 2.9 ± 1.3 less than the mean MoCA scores for females.DiscussionOur findings confirm the positive relationship between cognitive and physical function in older adults. Notably, we also observed superior performance in global cognition among females that was consistent across a broad spectrum of walking capacity

EBEX: A balloon-borne CMB polarization experiment

EBEX is a NASA-funded balloon-borne experiment designed to measure the polarization of the cosmic microwave background (CMB). Observations will be made using 1432 transition edge sensor (TES) bolometric detectors read out with frequency multiplexed SQuIDs. EBEX will observe in three frequency bands centered at 150, 250, and 410 GHz, with 768, 384, and 280 detectors in each band, respectively. This broad frequency coverage is designed to provide valuable information about polarized foreground signals from dust. The polarized sky signals will be modulated with an achromatic half wave plate (AHWP) rotating on a superconducting magnetic bearing (SMB) and analyzed with a fixed wire grid polarizer. EBEX will observe a patch covering ~1% of the sky with 8' resolution, allowing for observation of the angular power spectrum from \ell = 20 to 1000. This will allow EBEX to search for both the primordial B-mode signal predicted by inflation and the anticipated lensing B-mode signal. Calculations to predict EBEX constraints on r using expected noise levels show that, for a likelihood centered around zero and with negligible foregrounds, 99% of the area falls below r = 0.035. This value increases by a factor of 1.6 after a process of foreground subtraction. This estimate does not include systematic uncertainties. An engineering flight was launched in June, 2009, from Ft. Sumner, NM, and the long duration science flight in Antarctica is planned for 2011. These proceedings describe the EBEX instrument and the North American engineering flight.Comment: 12 pages, 9 figures, Conference proceedings for SPIE Millimeter, Submillimeter, and Far-Infrared Detectors and Instrumentation for Astronomy V (2010

Research priorities in the field of posttraumatic pain and disability: Results of a transdisciplinary consensus-generating workshop

© Copyright 2016 David M.Walton et al. Background. Chronic or persistent pain and disability following noncatastrophic \u27musculoskeletal\u27 (MSK) trauma is a pervasive public health problem. Recent intervention trials have provided little evidence of benefit from several specific treatments for preventing chronic problems. Such findings may appear to argue against formal targeted intervention for MSK traumas. However, these negative findings may reflect a lack of understanding of the causal mechanisms underlying the transition from acute to chronic pain, rendering informed and objective treatment decisions difficult. The Canadian Institutes of Health Research (CIHR) Institute ofMusculoskeletalHealth and Arthritis (IMHA) has recently identified better understanding of causalmechanisms as one of three priority foci of their most recent strategic plan. Objectives. A 2-day invitation-only active participation workshop was held inMarch 2015 that included 30 academics, clinicians, and consumers with the purpose of identifying consensus research priorities in the field of trauma-relatedMSK pain and disability, prediction, and prevention. Methods. Conversations were recorded, explored thematically, and member-checked for accuracy. Results. From the discussions, 13 themes were generated that ranged from a focus on identifying causal mechanisms and models to challenges with funding and patient engagement. Discussion. Novel priorities included the inclusion of consumer groups in research from the early conceptualization and design stages and interdisciplinary longitudinal studies that include evaluation of integrated phenotypes and mechanisms

First implementation of TES bolometer arrays with SQUID-based multiplexed readout on a balloon-borne platform

EBEX (the E and B EXperiment) is a balloon-borne telescope designed to measure the polarisation of the cosmic microwave background radiation. During a two week long duration science flight over Antarctica, EBEX will operate 768, 384 and 280 spider-web transition edge sensor (TES) bolometers at 150, 250 and 410 GHz, respectively. The 10-hour EBEX engineering flight in June 2009 over New Mexico and Arizona provided the first usage of both a large array of TES bolometers and a Superconducting QUantum Interference Device (SQUID) based multiplexed readout in a space-like environment. This successful demonstration increases the technology readiness level of these bolometers and the associated readout system for future space missions. A total of 82, 49 and 82 TES detectors were operated during the engineering flight at 150, 250 and 410 GHz. The sensors were read out with a new SQUID-based digital frequency domain multiplexed readout system that was designed to meet the low power consumption and robust autonomous operation requirements presented by a balloon experiment. Here we describe the system and the remote, automated tuning of the bolometers and SQUIDs. We compare results from tuning at float to ground, and discuss bolometer performance during fligh

Development and performance of the detectors and readout of the EBEX balloon-borne CMB polarimeter

The E and B Experiment (EBEX) is a balloon-borne polarimeter primarily designed to measure or set an upper limit on the B-mode polarization pattern of thecosmic microwave background (CMB). A precise measurement of degree angularscale B-mode polarization would provide compelling evidence in support of inflationary theories. In addition, EBEX was designed to characterize galactic dust bymeasuring the sky in three frequency bands, at 150, 250 and 410 GHz, and to measurethe B-mode polarization created by gravitational lensing of E-mode polarization.To accomplish these goals, EBEX employed a kilopixel array of transition edgesensor (TES) bolometers read out with a SQUID-based frequency domain multiplexed scheme. This system saw its first operation in a space-like environment during the EBEX engineering flight in 2009. More recently, during the 2012 to 2013Austral summer, EBEX flew its eleven day science flight. During this flight, theTES bolometer array was operated and tuned remotely from McMurdo station whileat float at 33 km above the Antarctic, and EBEX made its first measurement ofastrophysical sources.This thesis focuses primarily on the detailed implementation of TES bolometer detectors and the frequency domain readout scheme employed by EBEX. Thisincludes characterization of the bolometers, operation of the readout hardware andsoftware, and the cooling system developed to allow the readout to operate at float.It concludes with a bolometer calibration and a preliminary analysis of the bolometernoise during the long duration balloon flight.EBEX (“E and B Experiment”) est un polarimetre porte par un ballonstratospherique qui a ete concu pour fixer une limite superieure a la structure de lapolarisation des modes ‘B’ provenant de rayonnement cosmique. Une mesure precisedans l’ordre du degres des modes de polarisation B pourrait nous fournir une preuvefort probante en support des theories d’inflation. De plus, EBEX a ete concue pourcaracteriser la poussiere galactique en mesurant le ciel sur 3 bandes de frequences,150, 250 et 410 GHz, ainsi que les modes de polarisation de type B causes par leseffets de lentille gravitationnelles sur les modes polarisation de type E.Pour accomplir ceci, EBEX possede une matrice kilo-pixel de bolometres TESlus par des SQUIDs en utilisant une methode de multiplexage en frequence. Cesysteme a pris ses premieres mesures operationnelles dans un environnement quasi-spatial en 2009. Plus recemment, durant l’ete australe 2012/13, EBEX a effectue sa mission de vol scientifique de 11 jours. Durant ce vol, la matrice de bolometres TES a ete calibree et operee a distance a partir de la station McMurdo pendant l’instrument etait 33 km au-dessus de l’Antarctique, et faisait ses premieres observations de sourcesastrophysique.Cette these se concentre principalement sur l’implementation des bolometresTES et du systeme de lecture par multiplexage en frequence utilise par EBEX. Ceciinclut la caracterisation des bolometres, l’operation du materiel et logiciel de lecturedes bolometres, et le developpement du systeme de refroidissement qui permet delectures de fonctionner en vol a haute altitude. La these se conclut par l’etude dela calibration des bolometres et l’analyse preliminaire du bruit electronique mesuredurant le vol de long duree