Ruled Gratings for X-Ray and Far Ultraviolet Spectra.
Final rept. 1 Oct 69-30 Sep 72,
JOHNS HOPKINS UNIV BALTIMORE MD DEPT OF PHYSICS
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A brief resume is presented of The Johns Hopkins Universitys involvement in the development of seven diffraction ruling engines dating from Rowland 1881 to the present. A review of the literature indicates that many of the experimental limitations in the x-ray and far ultraviolet were due to shadowing mounds at the edge of each ruled line. Blazing, if carefully controlled, is effective in the longer ultraviolet but not in the x-ray region. A new process for making ruled gratings is described which eliminates the mounds that are so effective in destroying the diffracted intensity when the grating is used at small glancing angles as in x-rays. With close control of the ratio of the flat to groove width, one should be able to make a grating which maximizes intensity for a desired order and minimizes it for other selected neighboring orders. Technical details on various parts of the process are described. Author Modified Abstract