New:

Our contributions at ICPA-18 conference

Software for digital Doppler broadening spectroscopy developed in our group is now available for free download.

Software for positron annihilation

This page contains software for positron annihilation spectroscopy developed in the Positron annihilation group at The Charles University in Prague

PLRF code for fitting of positron lifetime spectra

A new code PLRF (version 19) was developed for decomposition of positron lifetime spectra. The PLRF code is based on the least squares fitting of positron lifetime spectra and utilizes a minimization routine MINUIT from the ROOT package developed at CERN.
Main features of the PLRF19 code:

  • Multiple positron lifetime spectra can be fitted simultaneously.
  • Positronium (Ps) contribution is considered as a double exponential component consisting of short lived para-positronium (p-Ps) and long lived ortho-positronium (o-Ps) component. Ratio of o-Ps and p-Ps contribution can be constrained.
  • Several models were implemented into the PLRF code:
    • independent exponential components
    • simple trapping model
    • diffusion trapping model.
    Physically relevant parameters of the model are varied to get best agreement with experimental positron lifetime spectra.
  • Description of the PLRF code can be found in the paper J. Čížek, Acta Physica Polonica A, 137, 177-187 (2020) .
  • A package containg PLRF 19 source file, input files and examples can be downloaded from from this link .
  • Installation: The package contains PLRF (version 19) source, examples of input files for various models and spectra which can be used for testing. The PLRF code is written in C++ and uses libraries from the ROOT package developed in CERN. In order to built the source into an executable file (in MS Windows 7 or higher) one has to do the following steps:
  • 1. Install ROOT on your computer. It is freely available here
  • 2. Install C++ compiler. I recommend Microsoft Visual Studio Community which is free (after registration). I strongly recommend to use Microsoft Visual Studio Community 2017 (i.e. the older version) because it has been tested and everything works fine. It is available here During installation choose to install C++ language
  • 3. Start Visual studio and create new project of type “empty project Visual C++” and add the source plrf19.cpp into it. This can be done through menu using “add existing files” In addition you have to include into the project all *.lib files from the ROOT directory root_v5.34.36\lib. This can be done again through menu using “add existing files” Finally you have to add path to root_v5.34.36\include into the INCLUDE variable of Visual studio. This can be done again using menu - project properties (Alt Enter) – Directories VC++ - directories to be included Now you can build the code. It will create executable file plrf19.exe.
  • 4. When the plrf19.exe is executed it expects that there is an input file with name plrf19.ini in the current directory. The input contains all information about spectra to be fitted, model to be used and initial values of all parameters. Its structure is described in the paper

Automatic fitting of sequences of positron lifetime spectra measured on pulsed positron beam MePS

PLRF19 enables automatic fitting of sequences of positron lifetime spectra for various energies of incident positrons measured on the user dedicated LINAC based pulsed positron beam MePS operated at Helmholtz Zentrum Dresden-Rossendorf . MePS spectra are prepared for PLRF19 analysis by a dedicated code MePS2dpl
  • Please see descrition of MePS2dpl code and its usage.
  • A package containing PLRF19 and MePS2dpl code can be downloaded here

Software for Digital Doppler broadening spectroscopy

A software collection representing a complete solution for digital measurement of Doppler broadening has been developed. This software is free and can be redistributed and/or modified under the terms of the GNU General Public License version 3.
The users are however kindly requested to cite the use of our codes in their works using the reference J. Čížek, M. Vlček, I. Procházka, Nuclear Instruments and Methods in Physics Research Section A, 623, 982-994 (2010) .

The Doppler broadening of annihilation photo-peak is measured by high purity germanium (HPGe) detectors, which provide excellent energy resolution. Description of the spectrometers for digital measurement of Doppler broadening and the approaches for analysis of sampled waveforms can be found in our paper:

J. Čížek. M. Vlček, I. Procházka, Digital spectrometer for coincidence measurement of Doppler broadening of positron annihilation radiation Nuclear Instruments and Methods in Physics Research Section A 623, 982-994 (2010)

The digital measurement of Doppler broadening can be performed in two modes:

  • semi-digital mode , where the pulses from charge sensitive pre-amplifiers of HPGe detectors are firstly shaped by pseudo-Gaussian filter in spectroscopy amplifiers in order to improve the signal-to-noise ratio and the signals from spectroscopy amplifiers are then sampled by digitizers;
  • pure-digital mode , where the pulses from charge sensitive pre-amplifiers of HPGe detectors are sampled directly.

The pure-digital mode enables to achieve the best energy resolution, while semi-digital configuration allows for a very efficient reduction of pulses damaged by pile-up or by ballistic deficit which leads to a spectrum of superior clarity. The semi-digital mode was successfully employed for precise measurement of positron annihilation-in-flight. Details are given in the paper:

J. Čížek. M. Vlček, I. Procházka, Investigation of positron annihilation-in-flight using a digital coincidence Doppler broadening spectrometer New Journal of Physics 14, 035005 (2011)

  • acquisition software for automated digital measurement of Doppler broadening using the Acqiris (Aglient Technologies) family of high speed digitizers.
    • documentation
    • Zip archive with C++ source code
    • The acquisition software enables a complete setting of digitizers and acquisition of waveforms.
    • Dacqn: program for acquisition in a mode with a single position of trigger (internal or external)
    • cDacqn: program for acquisition in a mode with two trigger levels switched during measurement
  • cmfit software for analysis of waveforms sampled in the semi-digital mode, i.e. pulses from HPGe detectors are firstly shaped by spectroscopy amplifiers and then sampled by digitizers.
    • documentation
    • Zip archive with C++ source code
    • The cmfit package includes the following programs:
    • sDCDB Gen : Generates synthetic data for testing purposes. These data can be used to verify functionality Cmfit program.
    • cmfit : Analyzes sampled waveforms, performs energy calibration, eliminates pulses with distorted shape using digital filters, creates 1D and 2D energy spectra
  • DCDB software collection for analysis of signals measured in the pure-digital mode, i.e. pulses from HPGe detectors are directly sampled by digitizers.
    • documentation
    • Zip archive with C++ source code
    • The DCDB package includes the following programs:
    • DCDB Gen : Generates synthetic data for testing purposes. These data can be used to verify functionality of DCDB MPI and DCDB Hist programs.
    • DCDB MPI : Analyzes raw pulses from detectors by fitting them with model function. Fitted parameters are stored in intermediate binary files read- able by DCDB Hist program.
    • DCDB Hist : Calibrates energy and generates 1D and 2D spectra from inter- mediate binary files created by DCDB MPI program.

Copyright (C) 2012  These programs are free software: you can redistribute them and/or modify them under the terms of the GNU General Public License version 3.
The users are however kindly requested to cite the use of our programs in their works using the reference J. Čížek. M. Vlček, I. Procházka, Nuclear Instruments and Methods in Physics Research Section A, 623, 982-994 (2010).