37725330
AKARI AND BLAST OBSERVATIONS OF THE CASSIOPEIA A SUPERNOVA REMNANT AND SURROUNDING INTERSTELLAR MEDIUM
We use new large area far infrared maps ranging from 65 to 500 μm obtained with the AKARI and the Balloon-borne Large Aperture Submillimeter Telescope missions to characterize the dust emission toward the Cassiopeia A supernova remnant (SNR). Using the AKARI high-resolution data we find a new "tepid" dust grain population at a temperature of ~35 K and with an estimated mass of 0.06 M sun. This component is confined to the central area of the SNR and may represent newly formed dust in the unshocked supernova ejecta. While the mass of tepid dust that we measure is insufficient by itself to account for the dust observed at high redshift, it does constitute an additional dust population to contribute to those previously reported. We fit our maps at 65, 90, 140, 250, 350, and 500 μm to obtain maps of the column density and temperature of "cold" dust (near 16 K) distributed throughout the region. The large column density of cold dust associated with clouds seen in molecular emission extends continuously from the surrounding interstellar medium to project on the SNR, where the foreground component of the clouds is also detectable through optical, X-ray, and molecular extinction. At the resolution available here, there is no morphological signature to isolate any cold dust associated only with the SNR from this confusing interstellar emission. Our fit also recovers the previously detected "hot" dust in the remnant, with characteristic temperature 100 K.
10833374
Optical design of the atacama cosmology telescope and the millimeter bolometric array camera.
The Atacama Cosmology Telescope is a 6 m telescope designed to map the cosmic microwave background simultaneously at 145, 215, and 280 GHz with arcminute resolution. Each frequency will have a 32 by 32 element focal plane array of transition edge sensor bolometers. The telescope and the cold reimaging optics are optimized for millimeter-wave observations with these sensitive detectors. The design of each is described.
119310570
Attitude determination for balloon-borne experiments
An attitude determination system for balloon-borne experiments is presented. The system provides pointing information in azimuth and elevation for instruments flying on stratospheric balloons over Antarctica. In-flight attitude is given by the real-time combination of readings from star cameras, a magnetometer, sun sensors, GPS, gyroscopes, tilt sensors and an elevation encoder. Post-flight attitude reconstruction is determined from star camera solutions, interpolated by the gyroscopes using an extended Kalman Filter. The multi-sensor system was employed by the Balloon-borne Large Aperture Submillimeter Telescope for Polarimetry (BLASTPol), an experiment that measures polarized thermal emission from interstellar dust clouds. A similar system was designed for the upcoming flight of Spider, a Cosmic Microwave Background polarization experiment. The pointing requirements for these experiments are discussed, as well as the challenges in designing attitude reconstruction systems for high altitude balloon flights. In the 2010 and 2012 BLASTPol flights from McMurdo Station, Antarctica, the system demonstrated an accuracy of < 5’ rms in-flight, and < 5” rms post-flight.
119263001
The Balloon-borne Large Aperture Submillimeter Telescope: BLAST
The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a suborbital surveying experiment designed to study the evolutionary history and processes of star formation in local galaxies (including the Milky Way) and galaxies at cosmological distances. The BLAST continuum camera, which consists of 270 detectors distributed between three arrays, observes simultaneously in broadband (30%) spectral windows at 250, 350, and 500 μm. The optical design is based on a 2 m diameter telescope, providing a diffraction-limited resolution of 30'' at 250 μm. The gondola pointing system enables raster mapping of arbitrary geometry, with a repeatable positional accuracy of ~30''; postflight pointing reconstruction to 5'' rms is achieved. The onboard telescope control software permits autonomous execution of a preselected set of maps, with the option of manual override. In this paper we describe the primary characteristics and measured in-flight performance of BLAST. BLAST performed a test flight in 2003 and has since made two scientifically productive long-duration balloon flights: a 100 hr flight from ESRANGE (Kiruna), Sweden to Victoria Island, northern Canada in 2005 June; and a 250 hr, circumpolar flight from McMurdo Station, Antarctica, in 2006 December.
14017836
The Balloon-borne Large-Aperture Submillimeter Telescope for polarization: BLAST-pol
The Balloon-borne Large Aperture Submillimeter Telescope (BLAST) is a sub-orbital experiment designed to study the process of star formation in local galaxies (including the Milky Way) and in galaxies at cosmological distances. Using a 2m Cassegrain telescope, BLAST images the sky onto a focal plane, which consists of 270 bolometric detectors split between three arrays, observing simultaneously in 30% wide bands, centered at 250, 350, and 500 μm. The diffraction-limited optical system provides a resolution of 30" at 250 μm. The pointing system enables raster-like scans with a positional accuracy of ~30", reconstructed to better than 5" rms in postflight analysis. BLAST had two successful flights, from the Arctic in 2005, and from Antarctica in 2006, which provided the first high-resolution and large-area (~0.8−200 deg2) submillimeter surveys at these wavelengths. As a pathfinder for the SPIRE instrument on Herschel, BLAST shares with the ESA satellite similar focal plane technology and scientific motivation. A third flight in 2009 will see the instrument modified to be polarization-sensitive (BLAST-pol). With its unprecedented mapping speed and resolution, BLAST-pol will provide insights into Galactic star-forming nurseries, and give the necessary link between the larger, coarse resolution surveys and the narrow, resolved observations of star-forming structures from space and ground based instruments being commissioned in the next 5 years.
10591697
SANEPIC: a mapmaking method for time stream data from large arrays
We describe a mapmaking method that we have developed for the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) experiment, but which should have general application to data from other submillimeter arrays. Our method uses a maximum likelihood-based approach, with several approximations, which allows images to be constructed using large amounts of data with fairly modest computer memory and processing requirements. This new approach, Signal and Noise Estimation Procedure Including Correlations (SANEPIC), builds on several previous methods but focuses specifically on the regime where there are a large number of detectors sampling the same map of the sky, and explicitly allowing for the possibility of strong correlations between the detector time streams. We provide real and simulated examples of how well this method performs compared with more simplistic mapmakers based on filtering. We discuss two separate implementations of SANEPIC: a brute-force approach, in which the inverse pixel-pixel covariance matrix is computed, and an iterative approach, which is much more efficient for large maps. SANEPIC has been successfully used to produce maps using data from the 2005 BLAST flight.
120848727
Final state branching ratio in the Be 7 decay
The fractional decay branch in the EC decay of $^{7}\mathrm{Be}$ leading to the first excited state of $^{7}\mathrm{Li}$ has been measured. $^{7}\mathrm{Be}$ ions from a beam produced by a tandem Van de Graaff accelerator were implanted into a surface-barrier detector; the decay $\ensuremath{\gamma}$ rays were then counted using a well-shielded Ge(Li) detector of known absolute efficiency. The resulting decay branch, (10.10\ifmmode\pm\else\textpm\fi{}0.45)%, is in good agreement with previously published values and in strong disagreement with a recent measurement.
119286890
Using cold atoms to measure neutrino mass
We propose a -decay experiment based on a sample of ultracold atomic tritium. These initial conditions enable detection of the helium ion in coincidence with the . We construct a two-dimensional fit incorporating both the shape of the -spectrum and the direct reconstruction of the neutrino mass peak. We present simulation results of the feasible limits on the neutrino mass achievable in this new type of tritium -decay experiment.
96922270
Application of accelerator mass spectrometry in aluminum metabolism studies
Abstract The recent recognition that aluminum causes toxicity in uremie patients and may be associated with Alzheimer's disease has stimulated many studies of its biochemical effects. However, such studies were hampered by the lack of a suitable tracer. In a novel experiment, we have applied the new technique of accelerator mass spectrometry to investigate aluminum kinetics in rats, using as a marker the long-lived isotope 26 Al. We present the first aluminum kinetic model for a biological system. The results clearly demonstrate the advantage this technique holds for isotope tracer studies in animals as well as in humans.
136391784
INVESTIGATION OF BERYLLIUM WINDOWS FROM CEA BUBBLE CHAMBER. Final Report
119647577
Reply to comment on ‘Using cold atoms to measure neutrino mass’
We discuss questions raised concerning the proposal of kinematically reconstructing the neutrino mass using an ultracold source of tritium atoms (Otten E W 2011 New J. Phys. 13 078001). We provide further details about our two-dimensional fit and emphasize the importance of simultaneously utilizing information from both the neutrino mass squared peak and the β-spectrum. We also explain how the simulation evolved over various drafts of the paper, and we comment on future directions for additional simulation work, including more detailed simulations of spectrometers and electromagnetic field variations.