PSI μSR Facilities: Available Software and Data Storage

Bulk μSR Data Format

The data files produced by the PSI μSR time-differential data acquisition programm are saved to a portable binary format (with extension ".bin" and 512 bytes/records and IEEE real-data format), called PSI-BIN. A description of the data format is given here. Since 2021, data are also saved in MusrROOT binary format (see below for a description).

Low-Energy μSR Data Format

The data files of LEM are written in an open file format called MusrROOT. This is much more flexible compared to the PSI-BIN format mentioned before. Eventually MusrROOT will replace PSI-BIN. A description of the MusrROOT file format can be found here.

Where to Find the Data Files?

The data-files are available from:

• Bulk Data: the AFS PSI tree (at the subdirectory: /afs/psi.ch/project/bulkmusr/data/xxx/ where xxx represents the instrument name).
• Bulk Data: the PSI-archive for older files (see information here).
• LEM Data: the AFS PSI tree (at the subdirectory:  /afs/psi.ch/project/bulkmusr/data/lem/ or /afs/psi.ch/project/nemu/data/his/ ).

Many programmes exist to analyze and manipulate these files (see list below -- note that some of these applications are no more supported).

Bulk μSR

A C++ class has been developed to read the μSR binary format produced at PSI with the td_bin format. It has been written as a hopefully easy to use and highly portable C++ code. A complete description of the class is provided here and the class Class_MuSR_PSI.zip can be downloaded here.

Low-Energy μSR

A complete description of a C++ class is provided here and the class can be downloaded from bitbucket.org.

• Analysis in time space—MUSRFIT: The programme musrfit has been developed by Andreas Suter and Bastian Wojek. It is a very versatile fitting software tool for analyzing time-differential μSR data. It is implemented in C++/ROOT and uses the MINUIT2 libraries developed at CERN for fitting data. User functions can also be defined. In addition simple Qt graphic user interfaces (musredit (Qt ≥ 4.6) / musrgui (Qt ≥ 3.3)) are available.
  • A user documentation for musrfit can be found here.
  • A technical description for musrfit can be found here.
  • The source code is publicly available at bitbucket.org under https://bitbucket.org/muonspin/musrfit.
  • Alternatively, it is possible to perform some basic fitting using our online web application musrfit.cgi. This application uses musrfit to perform the fits. Instructions on how to use musrfit.cgi are available here.
  • Since June 2023 musruser.psi.ch is not available for data analysis via ssh connection. The online web applications can still be used.
  • The by far easiest way to use musrfit is via nx.psi.ch from outside PSI. A detailed description on how to use this service can be found here. 
  • A simple ssh access to use musrfit  onto some machines using your PSI account (via hopx.psi.ch from outside PSI) is given here.
    • mpc2845.psi.ch
    • mpc1940.psi.ch
    • mpc1941.psi.ch (also accessible using a public account, ask one of the LMU team members for details).
    • Please remember to set up your account by adding the following lines to the .bashrc  file in your account,
      export ROOTSYS=/usr 
export MUSRFITPATH=/usr/local/bin
export DKS=/usr/local/dks
• Analysis in time space—WIMDA: This Windows based programme is developed and maintained by F. Pratt (ISIS). It can directly read PSI ".bin" data format.
  Details about WIMDA can be found here.

• Converting (basically) any format to any format:
  • Within the musrfit package a conversation tool is now available to convert basically from any µSR format into another. The tool is called any2many and can be invoked on the "musruser" machine or after installing locally musrfit.
  • Alternatively, you may use our web application SearchDB.cgi to search the LMU data base for specific runs, convert and download the corresponding data files in any format supported by any2many. Instructions on how to use SearchDB.cgi is available here.