Exploring the First Minute: New Technology for Measuring Color and Polarization Variations in Prompt Optical Emission

With the coming launch of the Swift satellite, there will be many new opportunities to study the physics of the prompt optical emission from gamma ray bursts with robotic ground-based telescopes. We discuss a new imaging system under development at Los Alamos National Laboratory that will provide simultaneous multicolor photometry of the rapidly evolving prompt optical emission in the first minutes after a burst trigger. This next generation system employs state-of-the-art photon-counting imaging technology at the focal plane of a rapidly slewing telescope. The imaging sensor is composed of an S-20 photocathode, stacked microchannel plates, and crossed delay line readout electronics that together are capable of measuring the time of arrival and positions for individual optical photons with 200 picosecond time resolution. The imager is coupled with electronically tunable liquid-crystal filters to provide essentially simultaneous linear polarization and multicolor photometric measurements of the prompt optical emission from a gamma ray bursts