Feasibility Study into the Use of Mechanical Choppers to Alter the Natural Time Structure of the APS

Introduction The prospect of extending static x-ray measurements into the time domain is an exci ting one indeed. The foundations for this extension have already been laid by some very innovative experiments (1) performed at existing storage ring sources. The enormous enhancement in brilliance that the APS will afford over existing sources will, I believe, foster a tremendous growth in the area of time-resolved x-ray experimentation. The growing interest in this field is evidenced by both the number of participants and their enthusiasm at an APS Workshop on Time-Resol ved Studies and Ultrafast Detectors (2) held on January 25-26, 1 988, at Argonne. In a very general way, one can divide time-resolved experiments into two broad classes: (1) those that take advantage of techniques that permit data to