WaFER: a tool to derive the focal surface of millimeter wave telescopes and characterize their optical response

摘要

In the framework of the Italian Space Agency (ASI) Technological Developments aimed at the measurement of theCosmic Microwave Background (CMB) polarization, a method to define and characterize focal surfaces of millimeterwave telescopes has been implemented in a software package named WaFER (Wave Front Error evaluatoR). Thepurpose of this tool is to rapidly optimize and characterize wide focal planes providing valuable information to study andoptimize high performance telescope configurations. This method is based on the GRASP9 Multi-Reflector GTD for thecomputation of the weighted wave front error and the software output is the 3D focal surface as the region thatminimizes this figure of merit, in terms of feed locations and orientations, for polarization measurements. In additionWaFER provides the main descriptive parameters of the main beams iteratively calculated with the GRASP9 PhysicalOptics, using the information derived for the evaluated focal surface. The method has been applied at several telescopeconfigurations and WaFER could be used to define the focal surface of any reflector antenna system that can be studiedwith GRASP9. It can be used to characterize the main beam descriptive parameters also in terms of polarizationproperties and straylight. Finally, an estimate of the computational time is reported for each computational step (focalsurface evaluation, main beam simulations, polarization alignment).© (2012) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.