File Type (CSV-related only):

Select Port:


Data Order:

Work in progress!

Work in progress!


Calibration using an nth degree polynomial:

E [keV] = cn xn + ... + c2 x + c1 (x ... Bin Number)

Coefficients will be computed automatically:

Sample Information

Device Information

This data will only be saved to JSON or XML exports.

Click Position:



0 cts



0 cts






Total: N/A cts

Net: N/A cts

Background: N/A cts

BG ratio: N/A %


Gamma MCA

Common Gamma-Ray Energies

List of gamma-ray energies of common isotopes.
Isotope Energy [keV]

Select a theme for Gamma MCA. System will automatically use your system theme.

Enable system notifications for serial events and similar (only if the window is not focused).

Modify the axes labels, plot title and data names by clicking on them.

Any positive integer is valid.

File must be of valid JSON format. Use only trusted sources!

File format for downloading a static plot. SVG looks the best.

Better FWHM calculation performance by assuming symmetrical peaks.

Any character is valid.

Number of (ADC) channels of the original device. Any positive integer is valid.

Any positive integer is valid.

Character transmitted at the end of every single data point. Any character is valid.

Formatted as hh:mm:ss. Any positive integer is valid. Serial recording will stop automatically when time runs out.

Determines how often the plot and the data are updated. Any positive float is valid, use integers for best performance.

Max number of serial input events buffered between plot refreshes. Any positive integer is valid.

Number of (ADC) channels of the serial device. Any positive integer is valid.

Automatically compute the energy resolution of all the peaks.

Use the new highlighting style for the peak finder. Turn off to use the old style.

Defines how many standard deviations of the peak the Gaussian shape is covering. 2 equals 95% coverage. Any positive integer is valid.

Decrease this if your data already looks pretty smooth, increase otherwise. Too high values can hide smaller peaks, too low values might generate false-positives. Any positive integer is valid.

Change this after adapting the Smoothing setting. Decreasing this will make the peak finder trigger on lower-amplitude peaks and vice versa. Any positive float is valid.

Maximum distance to search for isotopes around the peak energy. Any positive float is valid.

Gamma MCA is a complete progressive web app for gamma spectroscopy. It is free and open-source with online and offline functionality. You can import and export spectrum files or record new ones using the serial interface.

For a list of example spectra to help you get started head to the Gamma Spectrum Database.

For more information on the JSON file format head to the NPES-JSON GitHub repository.

Made free and open-source by NuclearPhoenix. Licensed under the GNU General Public License v3.0.

This site is part of the Open Gamma Project to provide modern and open-source resources for accessible gamma-spectroscopy.

Get the source code on GitHub.

Report issues and bugs on GitHub/Issues.

Questions? Discussions, Q&As and more can be found on GitHub/Discussions.

Version Site Notice

Install Gamma MCA (PWA) on this device. It will behave like any other native app and will work outside this browser.

Clears all settings, browser storage and reloads the page.