744jjjjjx   ,xP p*jThe stereographic projection code Crystal 2.29 for the Macintosh is now public domain, as of October 6, 1993. Crystal version 2.29 additions: 1. Automatically adjusts for large screens 2. Permits plotting of up to 1000 poles at once. (Memory is cheaper than when the original code was written.) "J&T poles" is a file of the poles used in the Johari and Thomas standard projections, and "FCC reflections" is self-explanatory. 3. Edit menu Pole/Circle selection lets you turn labels & circles on/off. 4. If you are interested in Laue patterns, look over the instructions below. The Laue option is not 100% tested for possible crashes. Laue Patterns Following is a suggested, short list of instructions to try out the Laue option of the Orientation menu of Crystal 2.29. The general concept is that the user can input the x-y coordinates of reflections on the Laue film, by means of a digitizing pad. (When time permits, I intend to add an option to just input x-y coordinates from the keyboard, so users without a digitizing pad can use the code.) Once a pattern has been input, it can be saved and recalled later. The code immediately converts the x-y coordinates to stereographic projection coordinates and displays an enlarged view of the central portion of the projection. (The outer, or basic circle will not be visible.) To solve the pattern, we construct great circles passing through the obvious lines of spots, and from the table of angles between the poles of these zone circles, we guess the solution by specifying the indices of two poles. The code then reverts from the Laue menus to the standard ones, and displays the great circles which would actually occur for our guessed solution, and if the solution is correct the spots will lie on low-index great circles and we can find the indices of any Laue spot just by using the Existing Pole selection of the Identify menu. To try the Laue code, first select the Laue option of the Orientation menu. This will change the menu structure. Now proceed as described below to experiment with solving the stored Laue pattern supplied, which is from an Al crystal with a crystal-to-film distance of 3 cm. 1. Use Recall Laue option of File menu to open existing file Laue 1. What you see is the inner part of the stereo projection of the Laue pattern. 2. Use Add Circles option of Edit menu. Click on two points through which a circle is to be drawn. I recommend the points at the ends of the rows, unless these happen to be far off the average circle. Code picks points closest to click point as usual. Add as many circles as you have densely populated hyperbolas. After adding circles, Laue 1 becomes Laue A. Each circle is lettered A,B,C etc. To see the poles of the circles, you can reduce diameter with Diameter option of Edit menu. (Hitting return gives diameter which fits screen.) Or, you can also use the Identify Circle option of Analyze menu, which will leave a label on the circle where you clicked. 3. Now use the Table of Angles option of Analyze menu. If you want to find angles between the points at intersections of your circles, you can use the Add Angle to Table option of Analyze menu, which lets you click on any two individual existing poles. If there is no pole at the intersection of two circles, you can construct a new pole with the Add Points option of the Edit menu; click on the two circles which intersect. 4. Now you can guess your solution by guessing the indices of two poles of interest, usually the intersections of two circles. For Laue 1, the three circles going through point 4 are all ~60 from each other, so we guess 4 = {111}. Also, 20 appears twofold and is ~35 from our {111}, so we guess it is a {110} pole. I believe you need to enter the exact indices, i.e. not just the form; that is, the angle between the poles of the exact indices you specify must be correct. If you say point 4 = [111] and point 20 = [110] you will get a correct result, but if you say point 4 = [111] and point 20 = [1-10] you will not. T.H. Kosel Univ. Notre Dame (219) 631-5642 e-mail: kosel@saturn.ece.nd.edu October 6, 1993  #4nopq   ef$4 !! !!!!!!!!! o1o1*o2 G 888 84 44 4  t IHH(FG(HH(d'@=/J@H -:ImageWriter ((nnn