SpecFitter

A program for gamma-ray spectroscopy or similar data analysis. Uses GTK to provide smooth rendering and (hopefully) an easy to understand interface.

Screenshots

Features

Display data

• Import data from one or multiple files and plot multiple spectra simultaneously:
  • Sum spectra together.
  • Overlay spectra, with either common or independent scaling on the y-axis.
  • Show spectra in a "stacked" view (tiled vertically with a common x-axis).
• Zoom and pan using the mouse (mouse wheel, click and drag).
• Display in linear or logarithmic scale on the y-axis.
• Calibrate spectra (with constant, linear, quadratic terms) to express bins in desired units.
• Rescale spectra, to perform operations such as background subtraction.
• Rebin spectra, with results displayed in real time.

Fit data

• Fit multiple Gaussian peak shapes (symmetric or skewed) on quadratic background (iterative least-squares fitter).
• Relative peak widths may be fixed (recommended for gamma-ray spectroscopy) or allowed to freely vary.
• Weight the fit by the data (taking background subtraction into account) or by the fit function. Or don't weight the fit at all.

Manage data

• Rename, or delete spectra from the opened session.
• Store custom views of multiple spectra using any of the available plotting modes.
• Double click anywhere on a plot to write/edit a comment there.
• The full session including comments and custom views can be saved to disk using the .jf3 (compressed) or .txt (ACSII) file formats.
• Export image files (.png format) at arbitrary resolution for use in presentations and publications.

Supported file formats

Read/write support

• .jf3 - Format containing one or more losslessly-compressed spectra with comments and customized views.
• .txt - A plaintext file of tab-separated values, can be copy-pasted to/from Excel or similar spreadsheet software. Each row repesents a bin/channel and each column represents a spectrum (single column needed for 1 spectrum, 2 columns for 2, etc.).
• .spe - Spectrum format used/generated by the RadWare software package, for example when using the 'ws' command in gf3.

Read-only support

• .C (ROOT macro) - ROOT histogram macro files (.C files generated using the File/Save option in a ROOT TBrowser). Supports TH1D, TH1F, and TH1I histogram types.
• .spe (Maestro) - Text format spectra exported in the ASCII SPE format from Ortec Maestro.
• .chn (Maestro) - Spectra exported in the Integer CHN format from Ortec Maestro.
• .mca - A 2D array of integers, with the first index denoting a spectrum number (array length up to 100) and the second index denoting a bin number (array length fixed to 32768 ie. 2¹⁵).
• .fmca - The same format as .mca except using floats rather than integers.

Format support notes

Some sample files that the program can open are available here (.zip archive).

Conversion code I made some films with friends during high school and in the decade or so after. I've backed up the master copies of the ones I have: Night Witness (2018) A feature length horror film. s for some of the above data formats are available in the FileConvTools code repository.

Getting started

Compatibility

Building the program from source has been tested on CentOS 7, Ubuntu 18.04/20.04, and Arch Linux (as of December 2021) under the GNOME desktop environment. It should work on any Linux distro that satisfies the listed build dependencies. It may be possible to build this on other platforms where GTK is available, but that hasn't been tested.

Build dependencies

• make
• gcc
• pkg-config
• GTK3

In CentOS 7:

sudo yum install gcc gtk3-devel

In Ubuntu:

sudo apt install build-essential libgtk-3-dev

In Arch Linux:

sudo pacman -S gcc make pkgconf gtk3

Build instructions

A Makefile is provided, build the program using:

make

sudo make install

This will place the specfitter binary in /usr/bin, a data-type definition file in /usr/share/mime/packages (to allow opening compatible files directly from the file manager), and a desktop entry file in /usr/share/applications (for desktop environment integration). These changes can be undone with:

sudo make uninstall

Usage tips

• Preferences are stored in a plaintext configuration file on a per-user basis at $HOME/.config/specfitter/specfitter.conf.
• When running the program from the command line, it is possible to automatically open files by specifying the filename(s) as arguments (eg. specfitter /path/to/file1 /path/to/file2).
• After fitting a spectrum, the onscreen fit can be cleared using the right mouse button.

Credits

Developer/Maintainer: Jonathan Williams