An improvement in a color guard flag pole weight is disclosed. The cover includes a periphery which, as viewed in plan, includes four first sides that are spaced apart from each other and four second sides each connecting ends of adjacent ones of the first sides. In at least one embodiment, to improve the cooling of detector elements which are accommodated in the detector housing, one or more ventilation openings, provided with at least one closure device to interact with centrifugal force regulators, are provided for an air flow to pass through. Each segment includes a retaining rim and each mounting stud includes a corresponding retaining ledge which, upon adequate penetration of the stud into the bushing, allow the segments to collapse under the urging of the resilient bushing radially inwardly inter-engaging the rim and ledges to hold the stud within the bushing. A signal-to-background determination module automatically determines multiple signal-to-background ratios based on fluorescence measurements of the fluorophore sample and the blank sample received from the spectrofluorometer. The Mach-Zehnder interferometer includes a plurality of phase modulators in one of its paths.