Abstract: A radiant electromagnetic energy collector has an elongated non-imaging concentrator which concentrates and directs radiant energy onto an elongated absorber having a helical conduit for a heat exchange fluid mounted in an evacuated glass tube. The concentrator has rounded ends which also function as concentrating surfaces to concentrate and direct radiant energy onto the ends of the absorber. The helical conduit within the evacuated tube is connected to input and output pipes leading to the exterior of the tube which pass through a seal situated within the cylinder formed by the helical coil. The collector has a flexible transparent cover which is stretched to a flat sheet and held in position by an interengaging channel and locking rod arrangement located about the periphery of the concentrator.