Tech Talk: Sandy Weinreb, NASA Jet Propulsion Lab
Thursday, December 8, 2022
A.V. Williams 2460
301 405 3114
Objectives and technology of the DSA-2000, an array to study the transient universe
In the past the objects observed in radio astronomy were the 21cm hydrogen line, thermal emission from planets in our solar system, and from unusual stars and galaxies which typically did not change in a human lifetime. In the new era many objects of interest vary on a millisecond basis and the era is often called “time-domain astronomy”. The objectives are pulses from neutron stars, time variation of planets around other stars, and emissions from the perimeter of black holes, and searches for emissions from other civilizations In many cases the direction in the sky of the unknown source is not known and the prime need is for survey speed rather than sensitivity to the radio flux from a direction pin-pointed by observations at other wavelengths.
These new objectives are best served by arrays of small telescopes. Caltech is designing the Deep Synoptic Array-2000, a 2000 element array of 5 m diameter telescopes to be located in Nevada, operating in the frequency range of 700 to 2000 MHz. The technology being developed for this array will be described including reflectors, feeds, low noise amplifiers (LNAs) , fiber-optic transmission over several km paths, and signal processing. Of special interest are theLNAs which are achieving 0.1dB noise figure without cryogenic cooling.
Sander Weinreb is presently an Emeritus Scientist at JPL and a Visiting Associate at Caltech. He received the B.S.E.E. and Ph.D. degrees from M.I.T. in 1958 and 1963 respectively. Most of his career has been in the administration or development of instrumentation in radio astronomy. His major accomplishments are the introduction of digital correlation techniques into radio astronomy, the discovery of the first cosmic molecular radio spectral line (OH), and the introduction of cryogenic transistor amplifiers to radio astronomy. From 1966 to 1988 he led the Electronic Division of National Radio Astronomy Observatory where he was responsible for the design of all electronics for the Very Large Array and all other telescopes operated by the observatory. Since 2006, Weinreb has devoted most of his effort in developments for the international Square Km Array (SKA) project and mentoring students including the supervision of five Ph.D. students in Electrical Engineering at Caltech. He has over 200 publications, has served on many review and visiting committees, is a Life Fellow of the IEEE and has received the Reber Medal, the Jansky Award, and the Weber Prize for contributions to instrumentation in astronomy. His current research activities are in the areas of very low noise amplifiers at ambient temperature and very large arrays for low frequency radio astronomy.