The Hydrogren Intensity and Real-Time Analysis eXperiment (HIRAX) is a 21 cm intensity mapping experiment in the Karoo region of South Africa that will consist of 1,024 six metre dishes operating interferometrically from 400 to 800 MHz; an initial 256-dish array is funded. The full experiment will have over 2,000 signal chains, each consisting of many individual components—dual-polarisation antennas, amplifiers, filters, cables, etc.—whose connections, locations and states need to be tracked as the experiment is deployed and modified. Data analysis requires accurate information about the physical location of each antenna and which digital channel it is connected to at any given moment in the observatory’s history. Identifying the particular components within each signal chain, which in principle can have unique calibration information, may also be needed in order to reach the high levels of precision required by HIRAX. This complex bookkeeping task requires specialised software, and Padloper is a package under active development to meet this need. It uses JanusGraph, an open source graph database, to represent hardware components as vertices and their connections as edges of a graph. A customwritten Python package populates the database and can be used to query the database for the experiment configuration at a given date and time. A web interface built with React interfaces to this package via a Flask server for user-friendly access and provides useful visualisation tools. Padloper is open source and could easily be deployed for any experiment that needs to track signal chains, such as the upcoming CHORD and PUMA radio interferometers.
|