| Profile metrology is very important for the manufacturing and application of optical elements.X-ray mirrors are key optical elements in synchrotron radiation facilities,extreme ultra-violet lithography,telescopes,X-ray free electron lasers and so on.In these areas,the quality of the X-ray is dependent on the quality of X-ray mirrors.Long trace profile system,for example the long trace profiler(LTP),the nano-optical measurement machine(NOM),are important instruments for the metrology of X-ray mirrors.To meet the state-of-art metrology requirement of better than 509)(6(9 in slope and 19)8)in height,many systematic error sources of the long trace profile systems need to be minimized or eliminated.Optical elements of the long trace profile system are primary systematic error sources which might introduce systematic errors of up to thousands of nano-radians.Systematic errors introduce by optical elements of the long trace profile system could be divided into two parts.One part of the systematic errors introduced by optical elements is due to the manufacturing defects of the optical elements and the other is due to aberrations of the f-theta system.It is very hard for traditional long trace profile systems to minimize these kind of systematic errors.In this paper,after analyzing the characteristics of these two kinds of systematic errors,we introduced the normal tracing method for the design of new type of long trace profile system,which could minimize these types of systematic errors.For the aberration introduced systematic errors,we also introduced a new design procedure for the design of pencil beam f-theta lens.Softerware simulation and experiment result have proved that the normal tracing method is worked for the design of new type of long trace profile systems which have minimal systematic errors introduced by optical elements.The design procedure for the pencil beam f-theta lens is also proved with the softerware simulation. |
