Upper Limit on the X-Ray Flux Associated with Gravitational Radiation

An upper limit in the x-ray flux accompanying pulses of gravitational radiation has been determined with relatively simple balloon-borne apparatus. The minimum detectable flux in space, approximately 2×${10}^{-5\mathrm{}}$ erg/${\mathrm{cm}}^2$ event, is about 9 orders of magnitude below the energy flux which produces the gravitational signals observed by Weber. Furthermore, it is lower than that attainable with the much more elaborate and difficult ground-based methods which have been suggested so far.