Glass Capillary Optics at CHESS
Don Bilderback

The CHESS capillary optics group (see http://capillary.chess.cornell.edu/) 
continues to develop its capability to draw hollow glass tubing into 
precision elliptically-tapered single-bounce x-ray optics that make 
most of the microbeam experiments possible at CHESS beam lines.  We 
are continually trying to improve the quality of the optics by making 
more precisely-figured parts as we improved the hardware/software tools 
on our LabView operated, custom-built drawing tower consisting of an 
precision linear air bearing + small-bore electric furnace.  The instrument 
allows us to soften the wall the borosilicate glass tubing of a few mm in 
diameter and stretch it to the proper shape as determined in advance by 
a web-based mathematical design program.

The hope in the long run is to make higher quality capillaries with slope 
errors below 50 microradians - our present level of performance - and figure 
errors of less than 1 to 2 microns.  The puller mechanics are undergoing 
some performance testing at present as we continue to produce specialized 
parts for various x-ray experiments.  We will continue to do "detective 
work" to try to figure out where the current slope errors are generated by 
the current drawing process and try to beat them down to even smaller 
levels.  Doing so will increase the performance of the resulting optics.  
The person selected to help us will join our 3-4 person group effort and 
be immersed in operating and improving our computerized instrument ion 
for glass drawing and its associated metrology.