This report was prepared as an account of work sponsored by the United States Government, Neither the United States nor the United States Atomic Energy Commission, nor any of their employees, nor any of their contractors, subcontractors, o r their employees, makes any warranty, expressed o r implied, o r assumes any legal liability or responeibility for the accuracy, completeness or usefulness of any information, apppratur , product or process discloeed, or represents that its use would not infringe privately owned rights. Prhtad in the United Stater oi America Available iKun the Wtiond T a c M d Marmaw filervice

No abstract

This report was prepared a s an account of Government sponsored work. Neither the United States, nor the Commission, nor any person acting on behalf of the Commission: A. Makes any warranty o r representation, expressed o r implied, with respect to the accuracy, completeness, o r usefulness of the information contained in this report, or that the use of any information, apparatus, method, or process disclosed in this report may not infringe privately owned rights; or B. Assumes any liabilities with respect to the use of,' or for damages resulting from the use of any information, apparatus, method, o r process disclosed in this report. As used in the above, "person acttng on behalf of the Commission" includee any employee o r contractor of the Commission, o r employee of such contractor, to the extant that such employee o r contractor of the Commission, or employee of such contractor prepares, disseminat~s, o r provides access to, any information,pursuaut to his employment o r contract with the Commission. o r his employment with such contractor.

This report w y prepared as an account of work sponsored by the United States Government. Neither the United States nor the Energy Research and Development Administration, nor any of their employees, nor any of Choir contractors, stibsnntmoI,trrs, o r their employees, makes any warrxnty, expresscd or implied, or assumes any legal liability or responsibility for the accuracy, completeness or usefulness of any information, apparatus, product or prucess disclosed, or represents that its use would not infringe privately owned rights.

Light weight beryllium baffle materials have been fabricated by laying down thick, fine grained Be coatings using magnetron sputtering on formable Be ingot sheet material. Six different coating process variations were used: three different bias voltage settings (-200 V, -50 V and no bias) were applied to either water cooled or thermally isolated substrates. A 20% solution of HF acid in ethanol was used to etch the Be coatings in order to increase light absorption. Scanning electron microscopy revealed significant variations in surface morphology of the etched coatings. Acid etching increased the number of light traps in the surface, particularly those below one micrometer in feature size, thus increasing light absorption in the visible region. Specular reflectance measurements from 400 nm to 50 .im revealed that thick coatings laid down with a -50 V bias and etched for one minute produced diffuse, light absorbing baffle surfaces with reflectivities less that 5% out to 40 m.