11-BM Data File Types

EPICS .mda

Files on 11-BM are collected using the Savedata routine in EPICS and stored in a binary (.mda) format. Note that this file contains intensity values for each of the 12 detectors separately. It is necessary to compute the 2theta values from the step size, starting angle and detector offsets. There are a small number of programs that can directly read these files. We typically use MDA2ASCII to translate them. We have been able to build the Dohn Arms' MDAUTILS for Linux, Mac and Windows. A recent version of CMPR can call MDA2ASCII automatically to directly plot the files.

When .mda format files are requested, the instrument calibration file appropriate for processing the data is also sent. This contains the wavelength, 2theta offset and sensitivity correction for each detector.

EPICS .asc

The files created by MDA2ASCII (.asc) can be read by humans and CMPR. As far as we know, they contain exactly the same information as in the .mda file, but are in ASCII. The size of the .asc file is about the same as the .mda file.

When .asc format files are requested, the instrument calibration file appropriate for processing the data is also sent. This contains the wavelength, 2theta offset and sensitivity correction for each detector.

GSAS data (.fxye)

GSAS supports many formats for powder diffraction data input. The FXYE format within GSAS has a header line followed by any number of comments (prefixed by a # character) a header line and then lines with 2theta (x100), intensity and standard uncertainty (estimated error) on the intensity value. This format may not be supported by other software that claims to read GSAS input files.

The GSAS data file produced in this manner has all twelve detectors merged into a pseudo-single detector intensity values. Uncertainties are reduced to account for the number of contributing detectors. Corrections are applied to the data to correct for the offsets between detectors, differences in sensitivity and minor differences in wavelength (typically on the order of ~1 eV or equivalently 0.003%). Data are extrapolated onto a regular spaced grid with interpolation between adjacent points. If merging is not wanted, CMPR can be used to creating 12 bank GSAS files from .mda or .asc files.

When .fxye format files are requested, instrument parameter files (.prm) are also generated. Several different extensions are commonly used for GSAS files, for example .raw, .gsa or .gsas. Bob used .fxye for this. Feel free to rename it if you wish.

GSAS parameter (.prm)

The instrumental settings used for data collection are described in GSAS in an "instrument parameter file". This defines the source as constant-wavelength x-rays, defines a default profile function and default instrument profile parameter values. These values are taken from a fit of NIST SRM 676 (Al₂O₃). The file is produced with the wavelength taken from the recent calibration file that was used to reduce the data.

TOPAS data (.xye)

The TOPAS file is similar to the .fxye file, except the header information is not included and angles are expressed in degrees, not centidegrees. The same merging process is used. The TOPAS file also includes the intensity values for each of the 12 detectors, interpolated onto the output grid.

Source code

This file (cmpr_alpha.tar.gz) contains the Tcl/Tk source code, plus Fortran source code for all the utility programs used inside. Runs on any platform where Tcl/Tk and BLT run.

Windows

This file (cmpr.exe) contains all files needed to run CMPR, including a Tcl/Tk interpreter and compiled versions for Windows of all programs, including MDAUTILS. Run this program to unpack and install CMPR. Note the self-installer will likely produce an error messages unless run from a Administrator account: Access denied writing C:\WINDOWS\lsb_un20.exe. If you choose "Skip", the installation will complete and CMPR will run properly. However, it will not be possible to uninstall the program from the Windows Add/Remove programs menu.

Some outdated instructions are available: Windows Install Instructions

Mac OS X

Intel Mac OS X

This file (osx_cmpr_i86.dmg) contains all files needed to run CMPR, including a Tcl/Tk interpreter and compiled versions for Mac OS X 10.4 with an Intel chip. Download the file, click on it (if needed) and drag the folder somewhere convenient. Some outdated instructions are available: Mac Install Instructions

PowerPC Mac OS X

This file (osx_cmpr_G4.dmg) contains all files needed to run CMPR, including a Tcl/Tk interpreter and compiled versions for Mac OS X 10.4 with an PowerPC (G4/G5) chip. Download the file, click on it (if needed) and drag the folder somewhere convenient. Some outdated instructions are available: Mac Install Instructions

CMPR OS X 10.5 (Leopard) bug:

I have seen CMPR freeze when started on 10.5 machines, apparently due to the logic program going into an infinite loop. Since that program is not of much use without a peak database, the solution is to delete file cmpr/logic/loadsub.

Linux (Intel)

This file (cmpr_linux.tar.gz) contains all files needed to run CMPR, including a Tcl/Tk interpreter and compiled versions for Linux on Intel chips (32 bit). Most images were compiled on a Fedora Core 6 machine, though some images are quite a bit older. To use these images a variety of shared libraries must be loaded, notably libg2c.so. Typically a number of packages must be installed to provide libraries: on FC6 these are compat-libf2c, libgcc, glibc.

Tcl/Tk & BLT on newer Linux distributions

I have heard of problems running CMPR with newer Linux distributions; or that it is hard to find BLT versions that will compile with the latest versions of Tcl/Tk. This archive, tcltk_ncnrpack_linux.tar.gz, contains a single-file Tcl/Tk/BLT distribution that has been reported to run on many versions of Linux. Run cmpr as

{path}/ncnrpack_linux4 {path}/cmpr/cmpr.tcl