The Track Engine - an FPGA implementation of a track-finding algorithm for the Icecube Neutrino Telescope

The Track Engine is an additional low-energy trigger and track reconstructor for the IceCube Neutrino Telescope. IceCube is built within the ice on the geographical South Pole, Antarctica. A neutrino interacting with an ice molecule might produce a muon, in turn emitting a trace of photons which can be detected by the detector. Efficiently finding low-energy tracks requires complex computations in realtime. An FPGA implementation was developed for this task. The Track Engine increases the trigger sensitivity with approximately 10% and it has a very low rate of false triggers. The rate that the Track Engine can process hits is a factor two to four faster than the average hit rate produced by the detector and hence Track Engine offers a comforting performance margin. Implementing a given algorithm in hardware yields superior performance compared to a software implementation. This paper presents the Track Engine system, the algorithm implemented, and discusses some of the challenges and solutions for transforming a given algorithm to a digital design implementation.