19 research outputs found
Peering beyond IRAS: The 100 to 350 micron dust emission from galaxies
No full textSeveral arguments can be made to study the continuum emission from dust in galaxies at wavelengths between the cutoff of the Infrared Astronomy Satellite (IRAS) survey (about 100 microns) and the shortest wavelength that is commonly accessible from the ground (about 350 microns). Some theoretical work (see the summary by Cox and Mezger 1989) indicates that there are very cool (T sub d less than or equal to 25 K) components to the dust emission that emit primarily at wavelengths between 100 and 250 microns. In fact, a significant fraction of the total luminosity, representing a large fraction of the dust mass in some types of galaxies, is emitted at long far-infrared wavelengths. In such cases, the cool dust must play a major role in regulation of the energy balance of the Interstellar Medium (ISM) and in shielding the cores of neutral clouds
A dual-polarized broadband planar antenna and channelizing filter bank for millimeter wavelengths
No full textAntenna-coupled bolometer arrays using transition-edge sensors
No full textWe are developing antenna-coupled Transition-Edge Sensor (TES) bolometer arrays for use in measurements of the CMB polarization. TES bolometers have many well-known advantages over conventional bolometers, such as increased speed, linearity, and the existence of readout multiplexers. Antenna-coupled bolometers use an on-chip planar antenna to couple light into the bolometer. The antenna directivity and polarization sensitivity, along with the potential for on-chip band defining filters and channelizing circuits, allow a significant increase in focal plane integration. This eliminates the bulky horns, quasioptical filters, dichroics, and polarizers which might otherwise be needed in a conventional bolometric system. This simplification will ease the construction of receivers with larger numbers of pixels. We report on the fabrication and optical testing of single antenna-coupled bolometer pixels with integrated band defining filters. We will also discuss current progress on fabrication of a bolometer array based on this design
A dual-polarized multichroic antenna-coupled TES bolometer for terrestrial CMB Polarimetry
No full textWe are developing dual-polarized multi-channel antenna-coupled Transition Edge Sensor (TES) Bolometers for Cosmic Microwave Background (CMB) Polarimetry in terrestrial experiments. Each pixel of the array couples incident power into the lithographed microstrip circuits with a dual-polarized broadband planar sinuous antenna who's gain is increased with a contacting extended hemispherical lens. Microstrip filter manifolds partition the two-octave bandwidth into narrow channels before terminating at separate TES bolometers. We describe the design methodology and fabrication methods used, and also the results of optical tests that show high optical throughput in properly located bands, as well as high cross-polarization rejection. We have explored two antenna feeding schemes that result in different quality beams and we comment on the relative merits of each. Finally, we quantify the increases in mapping speed that an array of our multichroic pixels might realize over traditional monochromatic pixel
A Log-Periodic Channelizer for Multichroic Antenna-Coupled TES-Bolometers
No full textWe have fabricated a dual-polarized multichroic antenna-coupled bolometer prototype pixel for use in focal planes of Cosmic Microwave Background (CMB) polarimetry experiments and for submillimeter observations of high redshift galaxies. We couple millimeter and submillimeter power onto the detector with a dual polarized sinuous antenna that has a continuous bandwidth of 60-250 GHz and we use a contacting extended hemispherical lens to boost the gain high enough to match the optics of a typical telescope. We partition each polarization channel into seen contiguous channels with a channelizer circuit that mimics the physiology of the human ear and then terminate each channel on a separate TES bolometer. Fourier Transform Spectroscopy demonstrates that the bands are near the designed locations with total receiver throughputs of 20-30%
An antenna-coupled bolometer with an integrated microstrip bandpass filter
No full textWe describe the fabrication and testing of antenna-coupled superconducting transition-edge bolometers for use at millimeter wavelengths. The design uses a double-slot dipole antenna connected to superconductingniobium microstrip. Band defining filters are implemented in the microstrip, which is then terminated with a load resistor. The power dissipated in the load resistor is measured by a superconducting transition-edge sensor (TES). The load resistor and TES are thermally well connected and are supported by a silicon nitride substrate. The substrate is suspended by four narrow silicon nitride legs for thermal isolation. The bolometers have been optically characterized and the spectral response is presented. This detector is a prototype element for use in an array designed for studies of the cosmic microwave backgroundpolarization
Antenna-coupled bolometer arrays using transition-edgesensors
No full textWe describe the development of an antenna-coupled bolometer array for use in a Cosmic Microwave Background polarization experiment. Prototype single pixels using double-slot dipole antennas and integrated microstrip band defining filters have been built and tested. Preliminary results of optical testing and simulations are presented. A bolometer array design based on this pixel will also be shown and future plans for application of the technology will be discussed
Sinuous-antenna coupled TES bolometers for Cosmic Microwave Background polarimetry
No full textWe are developing antenna‐coupled TES bolometers for CMB polarimetry that receive both linear polarizations over nearly two octaves of bandwidth. This ultra‐wide bandwidth is achieved with a novel adaptation of the sinuous antenna that integrates microstrip feed‐lines onto the arms of the antenna and uses a contacting extended hemispherical lens to focus the beam. It is challenging to achieve desirable antenna performance over such a wide band and our version of the sinuous antenna offers a unique solution. We have integrated this antenna with TES‐bolometers and report on a series of optical tests that demonstrate the antenna beams’s high symmetry, cross‐polarization rejection, gain, and optical efficiency over the operating band
