From Detector Counts to Calibrated Gamma Spectra
Gamma Workbench https://github.com/shotto42/gamma_workbench provides the usual functionalities to calibrate and display gamma spectra as well as to analyze the detector resolution. As a Tauri (Rust) based desktop app it can be installed on Linux, Windows and OSX.
It is designed to be used with the https://github.com/shotto42/MCA_H7 project and a suitable detector setup like a photo multiplier tube combined with a Csl(Tl) scintillation crystal. Other MCA hardware can also be used if it provides the same serial protocol described below. The STM32 hardware acquires the pulse-height histogram; Gamma Workbench turns that data into an interactive analysis workspace.
Watch your spectrum develop
Connect your MCA, select its serial port, and start collecting counts. Gamma Workbench displays 1,024 channels (10Bit ADC), with live updates and channel-by-channel inspection.
Switch between channel numbers and calibrated energy in keV, choose a linear or logarithmic count axis, and zoom or pan to investigate individual features. Hovering over the spectrum shows the raw channel counts, with calibrated energy. Light and dark themes make the workspace comfortable in different environments.
Calibration view: assign known energies to measured channels and check the resulting mapping:
Calibrate with the reference energies you need
Energy calibration connects measured channels to known spectral features. Choose a reference energy from the searchable isotope library, or enter a custom energy, then click the corresponding channel in your spectrum.
Calibration supports mixed isotopes: you can combine suitable reference peaks from different nuclides, and changing the selected isotope keeps your existing anchors. Exact channel selection is the default, with optional snapping to a nearby peak.
Three calibration methods are available:
1.) Piecewise linear interpolation: the default, passing through each reference anchor and extending the outer segments.
2.) Linear least-squares fitting: one straight-line fit across the selected anchors.
3.) Quadratic least-squares fitting: a curved mapping, with linear continuation beyond the reference range enabled by default.
Interpolation and linear fitting apply automatically after two anchors; quadratic fitting needs at least three.
Spectrum view: inspect raw counts, compare reference lines, and examine peak resolution in one workspace.
Measure peak width and explore isotope candidates
The interactive FWHM measurement tool helps assess detector energy resolution. Select an isolated peak to measure its width in channels and keV, together with resolution.
For spectral exploration, Gamma Workbench includes evaluated IAEA LiveChart/ENSDF reference data and isotope-line overlays. After calibration, automatic matching offers candidate isotopes and competing alternatives. These suggestions support comparison with known lines.
Keep your measurements and share the results
Save spectra as JSON files containing raw counts, calibration, and measurement metadata. Add a name and notes, reopen saved spectra as reference overlays, and compare measurements using each spectrum’s own calibration.
Export plots (png) for reports and project posts. Acquisition and analysis run locally inside the desktop application, built with Tauri, Rust, React, and TypeScript. No cloud account, database, or Python installation is required to run a packaged desktop build.
MCA hardware compatibility
Use Gamma Workbench with https://github.com/shotto42/MCA_H7 or another MCA HW that implements the current `stm32-sync-4100-le` serial stream:
Serial settings: 115200 baud, 8 data bits, no parity, one stop bit, no flow control.
Frame start: a separate four-byte synchronization marker, `FF FF FF FF`.
Payload: 1,024 cumulative unsigned 32-bit channel counts in little-endian order.
Total frame size: 4,100 bytes, including the synchronization marker.
Hardware Setup
Try Gamma Workbench
If you are building an MCA setup, experimenting with detector calibration, or comparing gamma spectra, take a look at the project and share your experience, ideas, or contributions.
The Gamma Workbench GitHub repository contains pre-build windows releases.
Gamma Workbench software, setup, and documentation on GitHub: https://github.com/shotto42/gamma_workbench
STM32 MCA hardware and firmware project on GitHub: https://github.com/shotto42/MCA_H7