Christopher Heiter
Title: Design of a Novel Multiband Heterodyn Receiver System for the APEX Telescope
Abstract:
As contribution to the APEX-II refurbishment MPIfR will deliver NFLASH, a state-of-the-art multicolor heterodyne spectrometer that will provide unique science opportunities to the APEX communities. The receiver allows simultaneous dual polarization observation in the frequency bands from 195-270 GHz and 385-510 GHz with an instantaneous bandwidth of 32+16 GHz. Using a dichroic select optics system the receiver can be expanded by a 850 GHz receiver which will enlarge the RF coverage for simultaneous observation. The 850 GHz channel will operate in the band from 780-950 GHz (ALMA band 10) using 2SB SIS mixers which will be partly produced in the MPIfR workshop.
Due to the modular structure of the receiver system observations for each combination of frequency bands can be performed resulting in high flexibility for specific scientific use cases and fast measurements.
In this talk the receiver system will be introduced and pre commissioning results will be presented. This includes beside others the progress of the in house 2SB mixer block production for ALMA band 10. After the talk there will be a lab tour providing the opportunity to take a look inside the NFLASH cryostat and to ask questions on the receiver.
Speaker: Tim Sprenger, Chair: Christopher Heiter
Title: Scintillometry: A gentle Introduction
Abstract:
The word scintillometry refers to methods that use scintillation
phenomena as their primary source of information. Scintillation is an
oscillatory amplitude variation of compact sources of radiation due to
the interference of different paths of propagation through an
intervening scattering medium. It can not only provide information about
the scattering medium but also about the spatial structure and velocity
of the source.
In this talk I will give an introduction to the basic concepts of
scintillometry with pulsars, whose radio emission is affected by
small-scale (~mas) diffracting material in the ISM of yet unknown
origin. I will also show one of my early results of trying to image
interstellar scattering screens.