Friday, August 2, 2013
By:
As we approach the conclusion of our work this summer, Darren and I, the two NASA interns, will be presenting our work on August 1st at the center-wide intern poster session at Goddard. We will also be giving oral presentations at the American Center for Physics the following week at the closing event for the SPS internship program. To give a flavor of my work, I have included below my abstract for the presentations.
Title: Blackbody Microwave Source for Cryogenic Detector Development
Abstract: I present an evolved design for a thermally isolated blackbody source operating at 90GHz and 120GHz, frequencies of interest to Cosmic Microwave Background measurements. My lab is developing transition edge sensor bolometers for the CLASS and PIPER missions to measure the CMB polarization; the source described here is under construction for use in the 150mK test package to measure the detectors’ response to CMB light. The design is optimized to minimize heat loading into the 150mK stage by employing a Kevlar kinematic suspension and additional thermal breaks. The blackbody light is coupled to a detector by means of an electroformed waveguide, which is mated to the source by an ultraprecise ring-centered flange design; this precision is critical to maintain the vacuum gap between the heated source and the cold waveguide, which is an order of magnitude smaller than the allowable misalignment of the standard military-spec microwave flange design. The source will provide at least 50% better thermal isolation than the existing 40GHz source, as well as a smaller thermal time constant to enable faster measurement cycles.
Alec Lindman