Gem software

GEM has two sets of software, ARIEL is used for analysing crystallographic data, and Gudrun and Open Genie is used to study disordered materials. This page gives an overview and links to the various programs available.

 

GEM Crystallography Software

ARIEL is a data reduction/visualisation package, developed primarily for the new high-intensity diffractometer GEM at ISIS. It was developed to address some fundamental concerns about GEM data handling, namely:

  • Flexibility: GEM is by design a highly flexible machine, suitable for crystallographic powder diffraction, liquid & amorphous diffraction, texture studies, diffuse scattering and even single-crystal studies. We needed a highly flexible software to deliver these objectives.
  • Memory and Speed: GEM can generate an enormous amount of data in short times. Uncompressed data files are in excess of 150 Mbytes, and 1 min measurements are entirely adequate for normal-size samples. The GEM software must be able to cope with this data rate, and match the current hardware limits.
  • Portability: ARIEL will be portable to the most common operating systems (Windows, Unix, VMS, Linux). The aim is to enable users to reduce raw data at their home institution on a PC or workstation, if they so desire.
  • Programmability: Users and instrument scientists must be able to write their own macro. Our aim is to give them the choice between the IDL syntax and a simple Genie-like interpreter (still under development).
  • Choice of file format: In ARIEL, data Input/Output (I/O) is done through the Open Genie Data Access Interface, which recognises a number of data format across platforms.

ARIEL is built as a fully instrument-independent, object-oriented code, that can be used for many different applications. ARIEL is written primarily in IDL, but makes some external calls to FORTRAN modules for data I/O (through the Open Genie Data Access Interface) and for some fast computation (e.g., Convert_to_Lambda). So far, ARIEL has been tested on 3 ISIS powder diffractometers: GEM, OSIRIS, and HRPD. The V. 3.2 version has a complete Graphic User Interface.

 

GEM Disordered Materials Software

There are two software programs which are required for correcting and analysing GEM data for disordered materials

1. The Gudrun program fully corrects neutron data, leading to a single structure factor which covers a wide range in Q as well as being fully corrected. It can be downloaded here.

2. The OpenGenie software can be used for visualising the data relatively quickly during the experiment, and for carrying out more careful data analysis on data corrected by Gudrun.  It can be downloaded here.

In addition to this, a package of programs which run in Open Genie have been developed to analyse GEM data and should be installed with Open Genie.  This package is called GEMSQRAW and can be downloaded here.

Installing Gudrun and Open Genie is relatively straightforward, but detailed instructions are given below along with the most likely errors which occur.

Installation instructions of Gudrun

Installation instructions for Open Genie and GEMSQRAW

For detailed information on using Gudrun and Open Genie to analyse data for disordered materials, follow the link to Disordered Materials Data Analysis

In addition to these programs, It is also recommended that XSECT is downloaded.  XSECT is a program which produces a file containing information on the sample which is then used to calculate the self scattering.  XSECT can be downloaded here, and a page giving information on how to use XSECT is here.

Finally a range of other useful software for analysing GEM data can be found here.

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