The Ebex Cryostat and Supporting Electronics

Sagiv, Ilan

doi:10.1142/9789814374552_0429

Cited by 8 publications

(7 citation statements)

References 13 publications

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“…The cryogenic performance and housekeeping electronics are discussed in detail elsewhere. 17 The cold optics alignment is verified using coordinate-measuring machine (CMM) measurements of the relative positions of the focal plane and lenses to reference points external to the cryostat, which allows for indexing of the cold optics to the warm optics. Before the engineering flight, CMM measurements verified that the optical alignment of all cold optics components was within 0.127 mm (0.005 in) in translation and 0.1 • in rotation of the nominal positions in the optics model.…”

Section: Overviewmentioning

confidence: 99%

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EBEX: a balloon-borne CMB polarization experiment

et al. 2010

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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 = 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.

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Section: Overviewmentioning

confidence: 99%

“…4 The performance of the cryogenics and receiver housekeeping during the flight is also available elsewhere. 17…”

Section: Overview Of the North American Engineering Flightmentioning

confidence: 99%

EBEX: a balloon-borne CMB polarization experiment

et al. 2010

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“…The SQUIDs in turn are connected in groups of four to digital frequency-domain multiplexing readout (DfMux) boards. 12 The design of the EBEX instrument is detailed elsewhere, 2,8,13 and the bolometer readout system is described in Hubmayr et al 14 and Aubin et al 15 EBEX completed a 13 hour engineering flight from Ft. Sumner, New Mexico in June 2009. In this paper we describe the software and data flow architecture that make up the EBEX control and monitoring systems.…”

Section: Instrument Descriptionmentioning

confidence: 99%

“…The time servers broadcast synchronization messages onto the CANbus, and distribute timing data to the DfMux boards and ACS via an RS-485 serial link that does not connect to the flight computers. The housekeeping and timing subsystems are described in Sagiv et al 13…”

Section: Systemsmentioning

confidence: 99%

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

Milligan¹,

Aubin²,

Baccigalupi³

et al. 2010

SPIE Proceedings

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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.

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“…We have developed multilayer epoxy-based dielectric AR coatings with more than 90% fractional bandwidth. While multilayer dielectric coatings have been developed [6][7][8], our moldable adhesive coatings have the advantage of being applicable for high dielectric constant curved lenses. Additionally, we can tune the dielectric constant of our layers, which allows for broad application of our coatings.…”

Section: Introductionmentioning

confidence: 99%

Epoxy-based broadband antireflection coating for millimeter-wave optics

et al. 2013

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We have developed epoxy-based, broadband antireflection coatings for millimeter-wave astrophysics experiments with cryogenic optics. By using multiple-layer coatings where each layer steps in dielectric constant, we achieved low reflection over a wide bandwidth. We suppressed the reflection from an alumina disk to 10% over fractional bandwidths of 92% and 104% using two-layer and three-layer coatings, respectively. The dielectric constants of epoxies were tuned between 2.06 and 7.44 by mixing three types of epoxy and doping with strontium titanate powder required for the high dielectric mixtures. At 140 K, the band-integrated absorption loss in the coatings was suppressed to less than 1% for the two-layer coating, and below 10% for the three-layer coating.

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The Ebex Cryostat and Supporting Electronics

Cited by 8 publications

References 13 publications

EBEX: a balloon-borne CMB polarization experiment

EBEX: a balloon-borne CMB polarization experiment

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

Epoxy-based broadband antireflection coating for millimeter-wave optics

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