NOVELTY - The collector has a receptacle evacuated to subatmospheric pressure and including a window and a reflector facing the window. The window and the reflector are exposed to the subatmospheric pressure in the receptacle. A fluid conduit (50) is extended through the receptacle between the window and the reflector. The reflector concentrates solar radiation passing through the window to the fluid conduit. The reflector includes a pair of concave radiation-reflective surface portions that meets along a longitudinal axis in a longitudinal plane.    USE - Collector e.g. flat-plate collector, evacuated tubes collector and solar concentrating collector, for collecting heat by absorbing solar radiation.    ADVANTAGE - The collector reduces manufacturing cost and improves reliability and efficiency through incorporation of the reflector and the fluid conduit into the evacuated receptacle. The collector reduces a number of fluid connections and associated convective losses, so that operating performance of the collector can be higher, thus avoiding increased manufacturing complexity. The collector contains the fluid connections within an evacuated space, so that insulation requirements can be significantly reduced. The collector allows fluid to allow for compact thermal collector designs and improve solar thermal collection efficiency with no adverse environmental impact. The collector allows elimination of evacuated tubes to allow dimensions of the reflector and the absorber in the collector to be significantly reduced, so that thickness of the window can be reduced significantly as compared to tube-based designs, thus reducing losses and weight associated with thicker windows.    DETAILED DESCRIPTION - The window is made of antireflective coating, which is porous. The collector includes fluid, which is super-critical carbon dioxide. INDEPENDENT CLAIMS are also included for the following:    (1) a method for manufacturing a solar thermal collector    (2) a solar collection method.    DESCRIPTION OF DRAWING(S) - The drawing shows a top view of a fluid conduit.    Fluid conduit (50)    Parallel linear segments (72-86)    Curved segments (88-98)