Abstract: A system and method for fluorescence excitation and detection having distinct optical paths is disclosed. A system for detecting fluorescence comprises a light source that emits an excitation light into an illumination tube; a plurality of collection optics located around an aperture in the illumination tube for collecting fluorescence; and a detector for determining the amount of fluorescence. A method for detecting fluorescence comprises emitting an excitation light from a light source into an illumination tube; directing the excitation light to an excitation filter; illuminating a sample with the excitation light to generate an emission light; and detecting the optical characteristics of the emission light using a plurality of collection optics located around the illumination tube.

Abstract: A flexible heating cover assembly for an apparatus for heating samples of biological material with substantial temperature uniformity includes a housing having a plurality of engageable enclosure components; a resistive heater having a plurality of heater element areas; a heater backing plate providing stability to the resistive heater; a force distribution system that distributes a force over the heater backing plate; and a support plate providing stiffness for the force distribution system, wherein the arrangement of the resistive heater, the heater backing plate, the force distribution system and the support plate provide substantial temperature uniformity among a plurality of sample tubes for receiving samples of biological material. The flexible heating cover assembly improves the uniformity, efficiency, quality, reliability and controllability of the thermal response during thermal cycling of the biological material.