. WORKSHOP~NOTES~FOR~LAUE~DATA~PROCESSING =======================================~ . Marjorie Harding and John Campbell October 1989 @ SECTION~1 . INTRODUCTION~ ============~ . A fairly full account of the principles used, in the majority of the programs in the Laue software suite, is given in Helliwell et. al (ref 1.) which should be read in conjunction with the instructions for the individual programs. It is also important to recognise that some of the basic framework is derived from the Cambridge/Imperial College suite of programs for the processing of monochromatic oscillation photographs of protein crystals (refs. 2,3). Thus the first objective is to find the crystal orientation and predict a set of spot positions. Then refinement is carried out for the crystal orientation angles, camera constants and all the parameters necessary to make the predictions accurate to, say, 0.05 mm. This is followed by integration of the optical density in a box around each predicted spot position and subtraction of the background. We are aware that there is room for improvement in a number of areas and program development is still going on. Suggestions and comments will be welcome. The demonstration examples are designed to help the beginner in Laue data processing to get experience with data which can be processed tolerably well by each of the main programs involved. Those already familiar with the processing of data using monochromatic radiation must 'think again' as the wavelength is now a variable! a) Examples^provided~ The two examples used are: 1) PF~ which is proflavine hemisulphate, (C13 H12 N3)2.SO4.(3.5)H2O, monoclinic, space group P21/C with 8 formula units per unit cell; excellent quality crystals were provided by Dr S. Neidle and have been used for many test photographs. (Structure determined, Jones and Neidle, 1975, Acta Cryst. B31~ 1324) This example works very straightforwardly at all stages. Because dmin is quite small (< 1 Angstrom) there are about the same number of reflections on the film as in the insulin example. 2) ZN~ which is 4 zinc insulin, space group R3, 18 molecules (of molecular weight about 6000) in the hexagonal unit cell given. The structure is known and well refined (eg Bentley, Dodson et al., Nature, 1976, 261~, 166-8). The photographs used here were taken in connection with studies of radiation damage and of the transformation to 2 zinc insulin. This example is not as straightforward as the first example, PF, at the initial stage of determining the orientation, because of the rhombohedral symmetry. Also at the integration stage, the spots are seen to be somewhat more elongated. In other respects, the examples provide similar experience. @ b) Files^~ Vax^ The digitised film images are in the directory CCPDISK:[LAUEDEM.FILM]. Before running the Laue programs for this workshop, the following assignment needs to be made: ASSIGN CCPDISK:[LAUEDEM.FILM] LFILM Using this logical name, the film image data file names are: LFILM:PF1A.DAT, LFILM:PF1B.DAT .... LFILM:PF1F.DAT and LFILM:ZN1A.DAT, LFILM:ZN1B.DAT .... LFILM:ZN1F.DAT The scans are on a 50 micron raster and the film images were read in from magnetic tape onto the VAX using the TAPEINS utility. All other files are on CCPDISK: and have the user identifier LAUEDEM (e.g. CCPDISK:[LAUEDEM]PF1_IN.GEN). It will be essential to have the .gen file for GENLAUE and the .ge1 and .ge2 files for INTLAUE in your own directory; others may be copied as you wish. In the subsequent text the directory will be indicated by the term LAUEDEM e.g. copy file pf1_in.gen from LAUEDEM. Convex^ The digitised film images are stored temporarily on a scratch disk in the partition /scr1/. If they have been wiped from this area then they may be copied via the ethernet to this area from the protein crystallography Vax DLVD. (The command 'getflms' is set up to do this if needed but requires a knowledge of the LAUEDEM id on the Vax!) The names of the digitised film images are: /scr1/pf1a.dat, /scr1/pf1b.dat .... /scr1/pf1f.dat and /scr1/zn1a.dat, /scr1/zn1b.dat .... /scr1/zn1f.dat The scans are on a 50 micron raster size. All other files are in the partition /priv4/ccp4/LAUEDEM/ and have read only access. You should copy any file that you want to use into your own working area. In many cases you will need to give them 'write' access. Individual files may be copied into your current directory, with the access modified appropriately, using the command: getdem filename e.g. getdem pf1_in.gen In the subsequent text the directory will be indicated by the term LAUEDEM e.g. copy file pf1_in.gen from LAUEDEM. c) Documents^~ In addition to this document, the following will be supplied: 'Introduction to the Laue software suite'. This contains a flow chart showing the normal sequence of programs used for processing Laue data. A copy of the paper 'The Recording and Analysis of Synchrotron X-radiation Laue Diffraction Photographs' (See reference 1) A copy of a few pages from the 'Oscillation film processing package' documentation indicating the convention for axes, missetting angles etc. (See reference 3) A page of hints on how to use the Convex. User documentation for the major programs which will be used. d) References^~ 1) Helliwell, J.R., Habash, J., Cruickshank, D.W.J., Harding, M.M, Greenhough, T.J., Campbell, J.W., Clifton, I.J., Elder, M., Machin, P.A., Papiz, M.Z. and Zurek, S. (1989) J. Appl. Cryst, 22~ part 5. 2) Arndt, U.W. & Wonacott, A.J., (1977). "The Rotation Method in Crystallography" Amsterdam: Netherlands. 3) Wonacott, A.J. (1980) Notes on a suite of programs for processing oscillation camera film data. @ SECTION~2 . FINDING~THE~CRYSTAL~ORIENTATION~-~NEWLAUE =========================================~ . Introduction^~ The program NEWLAUE has two uses: a) for solving for the crystal orientation when the unit cell and crystal to film distance are known, but not the orientation angles px, py, pz. This uses a file of spot positions made with the program SPOTIN which uses functions from the program GENLAUE and works in a similar way. b) for predicting Laue patterns given the unit cell, orientation of the crystal with respect to the beam and spindle, crystal to film distance, and the 'soft' limits (lambda-min, lambda-max and dmin). The program is very useful for learning about the effects of each of these parameters on the Laue pattern produced. You are reminded that the orientation angles are defined in the same way as in the oscillation film processing programs with the axes X parallel to the beam and Z parallel to the spindle. Example^1^-^proflavine^hemisulphate^(PF)~ File of spot positions: pf.dmp from LAUEDEM Crystal data: a=12.703, b=19.940, c=21.487, beta=92.29 degrees. Crystal to film distance: 61.0 mm To run NEWLAUE, type: laue newlaue Input the items of data as requested, noting the following: . wmin 0.3A, wmax 2.0A are reasonable dmin 1.4A is useful although the true dmin is < 1A radius is 59mm SYSTEM ... Carriage return gives Help information. ORIENT ... Choose option for 'misorientation angles' as used in oscillation film processing. Choose a* parallel to spindle and b* parallel to beam in this trial for consistency with our files. The camera type is the default (C1). DATSAV ... will write a .gen file with the current parameter values. This may be used by the program GENLAUE or re-input to NEWLAUE using the DATGET command. e.g. pf1_sav.gen . a) Solving^the^Orientation Leave PX, PY, PZ, SPINDL = 0. START is essential to calculate the reciprocal lattice points. PLOT is pretty but not essential at this stage. AUTO initiates the auto-indexing option. Note the following: . No indices available Input spot positions from file pf.dmp Error in positions < 1.0 mm Refine angles? Yes, and repeatedly till convergence. . This should give a solution with an rms deviation of < 0.3 mm. Keep a record of it. b) Checking^the^Orientation Perform the following command sequence: . Input PX, PY and PZ as found START to calculate reciprocal lattice etc. PLOT and check that displayed simulation agrees with photo. . c) Additional^Explorations To explore the properties of Laue patterns, try any or all of the following, or other variations: . Change PX, PY or PZ by 3 or 6 degrees Change spindle by 6 degrees Change wmin to 0.6A Change dmin to 2.0A or to 0.9A (slow!) Index some spots . Example^2^-^4ZN^insulin^(ZN)~ File of spot positions: zn.dmp Crystal data: a=80.7, c=37.6 (hexagonal axes, rhombohedral absences) Camera type is the default (C1) Crystal to film distance: 78.5 mm Suggested dmin about 2.3A. Choose a* parallel to spindle, c* parallel to beam Follow the general procedure learnt from example 1. Note the comments below on Auto-indexing. Comments^on^Auto-indexing~ The procedure depends on converting nodal spot positions to angles between simple reciprocal lattice vectors, and then matching them with calulated ones. 4 good nodals, all with low enough indices, are essential; more may or may not be helpful. The crystal to film distance must be correct and accurate and the shorter it is the better. When taking photos it may be useful to take a few extras at different spindle angles to increase the chance that one can be solved. Hints, comments for difficult cases: a) Raise maximum h**2 + k**2 +l**2 value; remember that an R lattice will require a higher value than a centred one. b) Raise error level slightly. c) Possibly vary crystal to film distance slightly (+ or - 0.5 mm) d) Success depends on 4-8 good nodals with well measured positions. Many more nodals just make the solution slower. Always try refining angles even if the rms looks very high. Comments^on^Properties^of^Laue~patterns It is useful to note the following: a) One spot may be the result of the superposition of several reflections, 'harmonics'. b) Short wavelength reflections occur predominantly near the film centre and long wavelength reflections predominantly nearer the outer edge, but they are intermingled. c) Increasing the dmin value makes the pattern sparser; it does not necessarily remove the outer (high theta) parts of it. d) Nodal spots, roughly speaking, are those which occur at the intersection of several festoons, and are well separated from their neighbours. They have simple indices and are often multiples e.g. 1 1 0 (with 2 2 0, 3 3 0 ...) 1 2 -1 (with 2 4 -2, 3 6 -3 ...) In subsequent programs a spot is defined as a nodal if none of its indices (of the lowest harmonic) is greater than a specified 'nodal index'. @ SECTION~3 . REFINING~THE~ORIENTATION~AND~GENERATING~THE~.GE~FILES =====================================================~ . Introduction^~ The program GENLAUE is used to refine the crystal orientation and produce files containing the indices and positions of spots to be integrated. It has many options an possibilities and the user should look at the flowchart (given in the program documentation and reproduced below) to help in its use. Refinement is likely to require quite a number of cycles, perhaps 5 - 15, with gradually changing conditions. It is usually desirable to refine all the 'hard' parameters - orientation angles, crystal to film distance etc. and, if appropriate, the cell dimensions - then to consider and optimise the soft limits, lambda-min, lambda-max and dmin and then to re-enter GENLAUE and write the files of predicted spot positions. A relatively high value of dmin can be used in GENLAUE, to save time, when the crystal parameters are being refined but, for the integration of the intensities, a realistic value of dmin must be used in order to assign multiple spots correctly - i.e. you cannot truncate to 'low resolution' data. The program will generate files name.ge1 and name.ge2 (name selected by the user) which contain the predicted positions for all the reflections in one film pack and space for the measured I and sig(I) values on all six films, as well as header information. The .ge1 file is for single and double Laue spots and the .ge2 file is for higher multiple spots. Example^1^-^proflavine^hemisulphate^(PF)~ Digitised film image: LFILM:PF1A.DAT (Vax) or /scr1/pf1a.dat (Convex) Carry out the following steps: 1) Copy^and^examine^the^.gen^file Copy the file pf1_in.gen from LAUEDEM to your own directory and examine it. PX, PY and PZ should correspond to those found from the autoindexing. Alternatively you may rename you output file from NEWLAUE as pf1_in.gen if you are satisfied with it. 2) Run^GENLAUE^to^refine^the^parameters The program is run by typing the command: laue genlaue For the input file specify pf1_in without an extension assuming that you have prepared a file pf1_in.gen as just described. A flow diagram is provided at the end of this section showing the various routes through the program. Choose a fairly high 'dmin' (e.g. 1.7) for the first run and use default values when in doubt. Choose the refinement option. Choose to predict all~ spots and to match on a threshold plot (The image file pf1a.img from LAUEDEM may be used to save time). **Warning**~ When printing a threshold plot there may be a considerable delay (about 1 minute) before plotting starts on the Convex so be prepared to wait. It starts much more quickly on the Vax though the time to completion is longer. This run should show convincingly that the patterns match approximately and should allow cursor input of pairs of observed and predicted spots to improve the match. Carry on into refinement and explore its possibilities - you may refine just px, py, pz or more parameters. When the predicted and observed patterns are matching within approximately 0.5 to 1.0 mm, it is safe to go over to refining 60-100 nodal spot predictions (choose an appropriate nodal index) against centre of gravity positions found by the program from the digitised image file (i.e. at this stage there is no need to display the plot or use the cursor). Bear in mind that the actual spot size is 0.3-0.4 mm, i.e. 6-8 rasters. It should be possible to refine to get a rms value of <= 0.05 (max 0.10) mm. 3) Writing^the^generate^files If you are satisfied with your refinement, use it in the 'generate' stage. Otherwise, start afresh in GENLAUE copying from the file pf1best.gen in LAUEDEM (containing our best parameters) into the file pf1_in.gen before re-running the program. Name the 'generate' file pf1 (-> pf1.gen, pf1.ge1, pf1.ge2) When asked the question about crystal to film distances, do~not accept the refined distances. Give the following spacings: 0.20 0.40 0.40 0.40 0.40 (mm) as the film pack is made up as follows: Fa Fb (F) Fc (F) Fd (F) Fe (F) Ff Note that, between stages 2 and 3, it would normally be necessary to experiment further to find good values of lambda-max lambda-min and dmin. Example^2^-^4ZN^insulin^(ZN)~ Digitised film image file: LFILM:ZN1A.DAT (Vax) /scr1/zn1a.dat (Convex) Saved image plot file: zn1a.img from LAUEDEM Generate parameters files: zn1_in.gen from LAUEDEM (approximate) zn1best.gen from LAUEDEM The procedure is very similar to that described for the first example bearing in mind the following: We used spot size 0.4mm, box size 0.75mm. Nodal index of 6, find 73 (out of 87) spots. Refined to rms of 0.034 mm. Name the generate file zn1 (-> zn1.gen, zn1.ge1, zn1.ge2) @ GENLAUE~FLOW~DIAGRAM . START~ | Input .gen file |<----------------------------------------------- Calculate spot positions | (Questions about overlaps, nodals etc.) | | | (Display predicted pattern) | | | --<--[NO]--Refinement?--[YES]---- | | | | | Spot posns. | (Refine another film -<-[.dmpfile]--from ?---[image file]-- | in pack? (Crystal to | | | film distance only)) | Fetch digitised image. | | | Find fiducials and | Calculate all spot | background. | positions, write to | | | .ge1, .ge2 files. | Display film image as | | | --<---[NO]------threshold plot ? | Questions about C-F | | | | distances. | | [YES] | | | Find centres of | | Rewrite .gen file w. | gravity of density (Save image as .img | additional parameters | around predicted file for quicker | | | positions display next time) | END~ | | | | | | Pick spot positions | | | with the cursor | | | | | | ------------------------- | | | | | Save spot positions | | in .dmp file | |--------------------------| | Display difference map | (obs-calc positions) | |<---------------- | Select parameters | | for refinement | | | | | Refine | | | | | (Display difference map) | | ( ) indicates optional choices | | | Further refine?--[YES]-- | | | [NO] | |---------------------- . @ SECTION~4 . INTEGRATION~USING~THE~PROGRAM~'INTLAUE' =======================================~ . Introduction^~ The examples use the profile fitting option in INTLAUE which gives better intensities for the weaker reflections than simple 'box' integration. They do not attempt to integrate spots closer than the spatial overlap limit as set in GENLAUE. Laue duffraction spots from good quality crystals will normally be circular in all parts of the film and comparable in size to the collimator used; normally in poorer quality crystals or radiation damaged crystals, the spots are elongated radially^ . For details of the program INTLAUE, see the program documentation and see also the flow diagram at the end of this section. Files^used^for^the^proflavin^hemisulphate^example~ . Digitised film images A-F: LFILM:PF1A.DAT .... LFILM:PF1F.DAT (Vax) /scr1/pf1a.dat .... /scr1/pf1f.dat (Convex) . The .ge files as made in the previous stage: pf1.ge1, pf1.ge2 The .gen file also created in the previous stage: pf1.gen Files^used^for^the^insulin^example~ . Digitised film images A-F: LFILM:ZN1A.DAT .... LFILM:ZN1F.DAT (Vax) /scr1/zn1a.dat .... /scr1/zn1f.dat (Convex) . The .ge files as made in the previous stage: zn1.ge1, zn1.ge2 The .gen file also created in the previous stage: zn1.gen Suggested^trials~ Start with the interactive processing of the first film using your own files from the GENLAUE run if you are fully satisfied, or otherwise copy our files from LAUEDEM if you are not. To run INTLAUE on the Vax, type: @CCPDISK:[LAUEDEM]INTLAUE.COM To run INTLAUE on the Convex, type: laue intlaue (Use the default 'terminal' as the reply to the prompt DATA: ) You may use default replies in answer to most of the questions except~ . Inner bin radius 200 (in rasters, edge of film is 1800) Outer bin radius 750 Approximate number of refinement nodals 200, 400 Box size 13 13 5 1 1 (probably - see printed profiles as check) . *Warning*: These last parameters are in fixed 5I5 format. On the Vax the input values line up with those displayed but on the Convex they are one character to the left. Leave the inner refinement threshold at 30 The 'inner refinement' should give an rms approximately <= 2 The 'outer refinement' should give an rms approximately <= 2 to 3 . After the printing on the terminal of: read y-scale .................. write y-scale .................. . interrupt the program with C. The program would go on at this stage to collect density, form profiles etc. The program is then re-submitted to run as a batch job. If you do not wish to wait, you may look at a sample output log file e.g. pfintlaue.log or znintlaue.log from LAUEDEM. To run the job in batch you will need to do the following: On the Vax: Copy pfbatch.com from LAUEDEM Then type submit the command file as follows depending on whether or not you are in a top level directory: Top level: submit/log=intlaue/notify pfbatch Subdirectory (where [directory] is the name of the sub-directory): submit/log=[directory]intlaue/par=([directory])/notify pfbatch On the Convex: Copy pfbatch.ctl from LAUEDEM Then type: laue intlaue (The file for DATA: is now pfbatch.ctl) Choose the batch option with a time limit of 150 seconds. The ZN example may be run in an analogous manner (znbatch.com on Vax, znbatch.ctl on Convex from LAUEDEM). @ INTLAUE~FLOW~DIAGRAM . START~ | Input files .ge1, .ge2, .gen digitised film image file | | - - - - - - - | | | | | 'Inner' refinement of parameters | | | - -<- - - - - | |<----------------------------------- | | - - - - - - - | | | | | | | 'Outer' refinement of parameters | | | | | - -<- - - - - | | | | Write improved parameters to .ge1, .ge2 files | | | Collect density | | | Form profiles - A film only, normally | | | Fit profiles, write intensities to .ge1, .ge2 files | | | Output summary, statistics | | | Any more films in pack? -----[YES]-------------- (end with F) | [NO] | END~ . - - - - Interactive use only, not batch @ SECTION~5 . FILM~PACK~SCALING~USING~THE~PROGRAM~'AFSCALE' =============================================~ . Introduction^~ This program needs to find and apply film factors between successive films of one pack; each film factor is a wavelength dependent function and is modelled as exp(alpha*lambda**3) with three different values of alpha (described as Victoreen coefficients; The coefficients k in the expression k*exp(alpha*lambda**3) are now kept equal to 1.0). The three alpha coefficients are for wavelength ranges separated by the discontinuities in the scaling functions at the Silver and Bromine absorption edges, at 0.49 and 0.92 Angstroms, due to the Silver and Bromine in the film. Files^used^for^the^proflavin^hemisulphate^example~ The intensities for films A-F in the .ge1 file: pf1.ge1 A file with starting approximation of coefficients: pf.vc from LAUEDEM Files^used^for^the^insulin^example~ The intensities for films A-F in the .ge1 file: zn1.ge1 A file with starting approximation of coefficients: zn.vc from LAUEDEM Running^the^program~ The program is run by typing the command: laue afscale After initial input of the intensity data (.ge1) file and the starting Victoreen coefficients file (.vc) the usual procedure for each film pair will involve: . D define - to select reflection pairs to be used and F fit - to evaluate the three alpha coefficients . followed by: Plot, Scale and/or Rsym to assess the results of the scaling The above steps will probably need to be repeated several times with variations in the parameters set by Define. When all film pairs, A/B ... E/F, have been thus fitted, the scaled and merged intensities are output to a file (.afout). The Victoreen coefficients may also be written to a file (.vc). See below for a summary of AFSCALE actions. Experiment with the program to get the best coefficients for the film pair A/B. Accept the coefficients in the .vc files provided for all the other pairs of films, B/C, C/D etc and output intensities for the film pack as pf1.afout or zn1.afout; zngood.vc and pfgood.vc are available if wanted. With the ZN data, use sigma limits such as 15, 15 to get sensible merging. Summary^of^the^program^actions~ . Input~ Define an input .ge1 file Load~ Load a .vc (approximate starting coefficients) file Define~ Selects reflections to be used | for finding parameters - on the | Repeat these basis of film pairs, exclusions | two till happy on I, sig(I) etc. } for all pairs | of films Fit~ Fits 6 parameters | Plot~ | Scale-R~ } Useful to monitor the goodness of the fit Rsym~ | Write~ Finally write new .VC parameters to file Output~ Finally write scaled and merged intensities to file . @ SECTION~6 . WAVELENGTH~NORMALISATION~USING~THE~PROGRAM~LAUENORM ===================================================~ . The program LAUENORM is used to perform an internal wavelength normalisation of the intensity data. Files^used^for^the^proflavine^hemisulphate^example The input intensities .afout files: pf1.afout (as created in the previous step or from LAUEDEM pf2.afout from LAUEDEM pf3.afout from LAUEDEM The input control data file: pfln.ctl from LAUEDEM Files^used^for^the^insulin^example The input intensities .afout files: zn1.afout (as created in the previous step or from LAUEDEM zn2.afout from LAUEDEM The input control data file : znln.ctl from LAUEDEM Running^LAUENORM The program LAUENORM is run by typing the command: laue lauenorm The input control data file DATA and intensities files LAUEHKL1, LAUEHKL2 etc. are prompted for (terminate the input of intensities files by typing a carriage return instead of a file name). The program should be run in batch. Additional^possible^trials It is possible to use LAUENORM on each individual pack of the insulin data and a control file znlnsingle.ctl is available to carry out these runs. Compare the normalisation curves found for the individual packs with that from the combined packs run. Look at the number of overlaps available for the scaling in the various cases and look at the internal agreement factors obtained. Try LAUENORM for one of the individual files for PF using the control data file pflnsingle.ctl. What causes the problems encountered? @ SECTION~7 . WAVELENGTH~NORMALISATION~USING~THE~PROGRAM~LAUESCAL ===================================================~ . The program LAUESCAL is used to perform a wavelength normalisation of the intensity data against a reference set of data. For Insulin, such a reference set is available and you may run LAUESCAL and compare the normalisation results with those obtained via LAUENORM. LAUESCAL normalises only a single pack at a time. Files^used^for^the^insulin^example The input intensities .afout files: zn1.afout (as created in the previous step or from LAUEDEM or: zn2.afout from LAUEDEM The input control data file : znls.ctl from LAUEDEM Reference set of intensity data : zn.lcf from LAUEDEM Running^LAUESCAL The program LAUESCAL is run by typing the command: laue lauescal The input control data file DATA, intensities files LAUEHKL, reference intensity file HKLIN are prompted for. Only one output LCF file name need be given (for HKLOUT1 and not for HKLOUT2) and no diagnostics file is needed. The program should be run in batch. @ SECTION~8 . PROCESSING~OF~DIFFERENCE~DATA~FOR~TIME~RESOLVED~STUDIES =======================================================~ . The program DIFFLAUE is used to prepare a file of difference Laue data scaled to a reference set of data. The program requires two input .ge1 files (for the two sets of laue data measured for the same crystal setting at different times) and an input reference set of data corresponding to the crystal state at time 1. Files^used^for^the^insulin^example The input intensities .ge1 files: zn1.ge1 (you own or from LAUEDEM zna1.ge1 from LAUEDEM The input control data file : zndl.ctl from LAUEDEM Reference set of intensity data : zn.lcf from LAUEDEM Running^DIFFLAUE The program DIFFLAUE is run by typing the command: laue difflaue The input control data file DATA, intensities .ge1 files LAUEGE1 and LAUEGE2 and the reference intensity file HKLIN are prompted for. Note: Both LAUEGE1 and LAUEGE2 prompts refer to .ge1~ files and the file names, with extensions, need to be specified. @ SECTION~9 . OTHER~PROGRAMS~OR~FACILITIES ============================~ . 1) To make a .dmp file for use in NEWLAUE laue spotin This program contains simplified sections from the program GENLAUE and is run in a similar manner for the specific purpose required. 2) To Unscramble Multiple Spots The program UNSCRAM may be run after AFSCALE. It uses the .ge1 and .ge2 files and the .vc file written by AFSCALE. The program may be run by typing the command: laue unscram 3) To get an overview of the spread and quality of data in the output from AFSCALE (or for individual films in .ge1 files) use the program initiated via the command: laue intanal The data control files intanal.ctl (for input from a .ge1 file) and intanal_afout.ctl (for input from a .afout file) are available from LAUEDEM. 4) The program LCHK analyses the distribution of symmetry_unique reflections in a Laue pattern. LCHK is intended to complement NEWLAUE and most of the conventions assumed in NEWLAUE are followed in LCHK. A menu allows for the input of parameter values and for the selection of a number of different commands for providing analyses of the data which would be collected for various combinations of crystal settings. The program is run by typing the command: laue lchk 5) To read film images from tape onto the Vax, use: TAPEINS To read film images from tape onto the Convex, use: mdtape