Introduction
PALSfit is a computer program for analysing spectra that are measured by positron annihilation lifetime spectroscopy (PALS). PALSfit is based on the well tested PATFIT program, which has been used extensively by the positron annihilation community.   Taking advantage of the windows interface, a number of new user friendly facilities have been incorporated, in particular graphics displays.

PALSfit is composed of two modules for fitting of positron lifetime spectra, PositronFit and ResolutionFit. In both modules a model function will be fitted to a measured lifetime spectrum. The model function consists of a sum of decaying exponentials convoluted with a resolution function, plus a constant background. The time resolution function is described by a sum of Gaussians which may be displaced with respect to each other. Various types of constraints may be imposed on the fitting parameters.

In the PositronFit module, the fitting parameters to be extracted from a measured spectrum are the lifetimes and intensities of the lifetime components. A correction for positrons annihilating outside the sample can be made as part of the analysis. In the ResolutionFit module, parameters determining the shape of the time resolution function can be fitted. The extracted resolution function may then be used in PositronFit.

Graphics displays are provided to ease the selection of some of the input parameters and to display results of spectrum analysis. The results are also available in a text window.

PALSfit is verified on Windows-XP.

 
Documentation
The documentation of the PALSfit program consists of two parts. One part is a report, which describes its mathematical foundation and includes a description of some features of the programme. The other part is a hands-on description of the windows user interface.

The documentation is available as pdf files:
      Mathematical foundation is found at this link to Risoe-R-1652 (998 kB)
      Hands-on User guide (in progress)

Additional references:   Risų-M-1279   Risų-M-1399   Risų-M-1400   Risų-M-2740

 
Price
The price of the full PALSfit version is EUR 700 with a 50% discount for those who have previously bought the PATFIT program.

The demo version is free of charge.

 
How to acquire PALSfit
To be able to run the PALSfit program, a license key is required.
To obtain this key, please print the standard PALSfit License Agreement, fill it out, sign it and e-mail a scanned copy or fax or post it to:

Morten Eldrup
Materials Research Division
Risø National Laboratory for Sustainable Energy
Technical University of Denmark
P.O.B. 49
DK-4000 Roskilde
Denmark

phone: +45 4677 5728
fax: +45 4677 5758
e-mail:palsfit@risoe.dtu.dk

You will then receive the license key by e-mail. An invoice will be sent to you later.

The full version of PALSfit, including test data, can be downloaded here (PALSfit version 1.64 - self extracting).

The PATFIT program package (without the GUI interface) is available free of charge for licensed PALSfit users.

 
Free demo version
A demo version of PALSfit can be downloaded free of charge. It serves to demonstrate the main features of the program but has limited functionality (for example, only the PositronFit part is active, the number of channels and lifetimes are limited etc.). Data for testing the program are included in the package.

Download selfextracting demo (PALSfit_demo version 1.64)

 
Authors
Jens V. Olsen, Peter Kirkegaard, Niels Jørgen Pedersen and Morten Eldrup

Risø National Laboratory for Sustainable Energy, Technical University of Denmark
Frederiksborgvej 399 - P.O.B. 49 - DK-4000 Roskilde, Denmark

e-mail: palsfit@risoe.dtu.dk