spec - Local Sector 7 web page

name and its arguments. (Scans invoked as hscan or kscan execute the basichklscan ,scans such as lup or dscan execute ascan ,etc.) The next line is the dateand time the scan was started. Following that, the #T control line indicates that thescan was counting to time and for what duration at each point. A #M would indicatecounting to monitor.The next lines give information that describe the diffractometer configuration at thestart of the scan. Following #G0 are the current values of the four-circle parameters,which are defined four-circle macro file, macros/fourc.src. Following #G1 are the currentparameters describing the crystal lattice and orientation matrix. The identificationof these parameters is in the macro file macros/ub.mac. The #Q line gives theH, K, L coordinates at the start of the scan, while the #P0 line gives the motor positionsat the start of the scan with each column corresponding to the motor names inthe #O0 line of the scan header. The 7 after #N indicates there will be seven columnsof data in the scan, and the #L line gives the names for each column, each name separatedfrom the other by two spaces. The detector counts are always placed in the lastcolumn, preceded by the monitor counts, if counting to time, or the elapsed time forthat data point, if counting to monitor. The Epoch column has the number of secondselapsed from the time of the #E at the start of the file.Following the scan header is the scan data. These are just lines of space-separatednumbers that correspond to the column headers given with #L . Intervening #C commentlines may lie within the rows of data if, for example, the scan was aborted andthen restarted with the scan_on macro. Otherwise, the data continues until the nextnon-comment control line or blank line.Youcan develop your own programs and scripts to extract data from the spec datafile, or you may want to use the scans.4 user function that is part of the C-PLOT package,or the stand-alone scans program that is based on scans.4.Scans .4The C-PLOT user function scans.4 reads in files of ASCII data according to a modestset of conventions. In particular, scans.4 manipulates the X-ray scattering data fromthe spec data files, doing scan averaging, background subtraction, data normalizationand error bar calculation. The C-language source code to scans.4 is always availableon your system, is liberally commented and should always be consulted if thereis any question as to what operations are being done on your raw data points.The scans.4 user function can be invoked from C-PLOT either as,orPLOT-> fnscans.436 USER MANUAL AND TUTORIALS INTERIM WORK-IN-PROGRESS (8/16/01) NOT FOR GENERAL DISTRIBUTION