On Kirkpatrick-Baez telescopes with adjustable X-ray optics

High resolution spectroscopy is the most favored objective of the next X-ray astronomy mission. A longer term goal is the development of a very large area X-ray telescope whose angular resolution and effective area are superior to the Chandra X-Ray Observatory. Adjustable X-ray optics with thin piezoelectric coatings is a methodology that may be capable of accomplishing that goal. It consists of applying piezoelectric coatings to the rear of a mirror substrate, which will be thermally slumped to the approximate figure. The figure is optimized by applying voltages to the piezoelectric coatings. Near term spectroscopy mission can benefit from higher angular resolution and a Kirkpatrick-Baez telescope should be considered as an alternative to the Wolter telescope. Adjustable X-ray optics technology should be very effective in refining the resolution of a KB telescope. When the thermally slumped mirrors of either the front or rear section are assembled and illuminated by a parallel visible light or X-ray beam line, line images formed by individual mirrors can be isolated by a moveable slit. With the piezoelectric controllers acting in only dimension the figure of each mirror can be optimized sequentially completely under computer control. The front and rear sections can be tuned independently and then joined with rather lenient tolerances. Dispersing along the 45 degree direction between the two orthogonal KB axes reduces the effect of scattering and figure errors similar to what is accomplished by using only part of the azimuth of a Wolter mirror.