PSI μSR Facilities: Available Software and Data Storage

Bulk μSR Data Format

The data files produced by the PSI μSR time-differential data acquisition program were originally saved to the portable binary format called PSI-BIN. This has the extension ".bin", features 512 bytes/records, and stores data in the IEEE real format. A description of the bin format is given here. Since 2021, data are also saved in the MuSrROOT binary format. Since 2027, PSI μSR data will be saved in the MusrROOT binary format only.

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 above. MusrROOT is gradually replacing 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 the NFS PSI tree at the following directories:

• Bulk Data: /psi.ch/group/lmu/public/data/xxx/his/, with xxx being the instrument name.
• LEM Data: /psi.ch/group/lmu/public/data/lem/his/

Many programs can analyze and manipulate these files (see list below - please note that some of them are no more supported). For further details please refer to the μSR Data Archives.

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 domain — MUSRFIT: The musrfit program was developed by Andreas Suter and Bastian Wojek. It is part of a versatile framework 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, musredit, a simple graphical user interface running under Qt (≥ 4.6), is 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 domain — WiMDA: This Windows based program is developed and maintained by F. Pratt (ISIS). It can directly read the PSI ".bin" data format and MusrRoot data via conversion to the ".bin" 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.

LMU and Groups

• Laboratory for Muon Spin Spectroscopy (LMU)
• Low-Energy Muons Group
• Bulk-µSR Group 

PSI User Facilities Newsletter

Current News from PSI photon, neutron and muon user facilities

MuonSources.org

ISMS

The International Society for µSR Spectroscopy (ISMS).