72 research outputs found
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 flight
EBEX: the E and B Experiment
The E and B Experiment, EBEX, is a Cosmic Microwave Background polarization experiment designed to detect or set upper limits on the signature of primordial gravity waves. Primordial gravity waves are predicted to be produced by inflation, and a measurement of the power spectrum of these gravity waves is a measurement of the energy scale of inflation. EBEX has sufficient sensitivity to detect or set an upper limit at 95% confidence on the energy scale of inflation of < 1.4 × 10^(16) GeV. This article reviews our strategy for achieving our science goals and discusses the implementation of the instrument
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 flight
Effect of Instrumental Polarization with a Half-Wave Plate on the -Mode Signal: Prediction and Correction
We evaluate the effect of half-wave plate (HWP) imperfections inducing
intensity leakage to the measurement of Cosmic Microwave Background (CMB)
-mode polarization signal with future satellite missions focusing on the
tensor-to-scalar ratio . The HWP is modeled with the Mueller formalism, and
coefficients are decomposed for any incident angle into harmonics of the HWP
rotation frequency due to azimuthal angle dependence. Although we use a general
formalism, band-averaged matrix coefficients are calculated as an example for a
9-layer sapphire HWP using EM propagation simulations. We perform simulations
of multi-detector observations in a band centered at 140\,GHz using \LB
instrumental configuration. We show both theoretically and with the simulations
that most of the artefacts on Stokes parameter maps are produced by the dipole
leakage on -modes induced by the fourth harmonics and
. The resulting effect is strongly linked to the spin-2 focal
plane scanning cross linking parameters. We develop a maximum likelihood-based
method to correct the IP leakage by joint fitting of the Mueller matrix
coefficients as well as the Stokes parameter maps. % by modifying the standard
map-making procedure. We show that the residual leakage after correction leads
to an additional noise limited uncertainty on of the order of ,
independently of the value of the Mueller matrix coefficients. We discuss the
impact of the monopole signal and the potential coupling with other systematic
effects such as gain variations and detector nonlinearities.Comment: 36 pages, 10 figures, submitted to JCA
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 l = 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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