Radiometric surveys now capture more detail than ever. Modern detectors routinely collect 512, 1024, 2048 or even 4096+ spectral channels, and drone‑borne systems have opened new frontiers for mapping.
But while acquisition technology raced ahead, the software to process that rich data often felt like a step back in time. We heard a consistent story from geoscientists: processing radiometric data wasn’t straightforward. The reasons were clear:
- Workflows were fragmented across legacy tools (i.e. Praga and 256‑channel Radiometric Processing extensions).
- Steps weren’t always intuitive, especially for users who only process radiometric data a few times a year.
- Validating corrections was time‑consuming, with little transparency into how the data was being adjusted.
- Legacy tools simply couldn’t handle the channel counts or behaviour of today’s instruments.
That’s why Seequent and Medusa Radiometrics formed a partnership with a single goal: to build a modern radiometric processing workflow that geoscientists can trust, follow, and return to with confidence.
A partnership forged by user feedback
This collaboration brings together decades of expertise. Medusa Radiometrics is a leader in gamma‑ray spectrometry known for compact, rugged detectors used on everything from aircraft to drones and agricultural vehicles. Their experience highlighted the need for a clean, reproducible workflow for modern, high-resolution data.
Seequent’s focus was complementary: to redesign the radiometric tools in Oasis montaj into a transparent, structured process that aligns with recognized standards and surfaces every correction step clearly.
“Our customers are deploying high-resolution detectors in challenging environments,” says Han Limburg, Director at Medusa Radiometrics. “They need a software workflow that is as modern and robust as their hardware. Partnering with Seequent allowed us to help build that bridge.”
Together, we’ve redesigned radiometric processing in Oasis montaj to make modern datasets easier to process and interpret with confidence.
Related content:
* What’s new in Oasis montaj 2025.1
* Medusa Radiometrics
* Introduction to Spectral Smoothing using the Radiometric Processing System in Oasis montaj
* Register for the Radiometrics Mastery session
Introducing the new Radiometrics Extension in Oasis montaj
Available in Oasis montaj 2025.2, the new Radiometrics Extension replaces the 256-Channel and Praga Radiometric Processing Extensions with a single, unified workflow. It delivers an end-to-end sequence designed for clarity and consistency.
Full‑extent ternary radiometric map produced in Oasis montaj, showing potassium, uranium and thorium variations.
Here’s what it brings to Oasis montaj:
Modern sensor support, without limitations
Where older tools required workarounds or downsampling, the new extension is built for today’s instruments. It fully supports:
- High-channel data, including 512, 1024, 2048, and 4096+ spectral windows
- The full array limits available in Oasis montaj
- Detectors based on traditional crystals and emerging materials (e.g., robust cesium iodide or new polymer-based systems).
This means radiometric data from any platform (aircraft, drone, vehicle, or handheld system) can be processed consistently in one place, ready for interpretation alongside your magnetic and gravity data.
Ternary K–Th–U radiometric data displayed with satellite imagery for surface context
A guided workflow aligned with IAEA best practice
The extension brings the standard radiometric correction sequence into a clear, logical order that reflects the structure of the International Atomic Energy Agency’s (IAEA) TECDOC-1363 guideline.
Each major stage is presented individually, so you can see exactly what each correction is doing:
- 1. Energy calibration: Aligns measured channels with expected energy positions using calibration peaks.
- 2. Background corrections: Tools for aircraft and cosmic background adjustments reflect the IAEA guidance to remove non geological contributions before spectral analysis.
- 3. Radon and height corrections: Addresses atmospheric radon and variations due to survey flight height.
- 4. Dead time corrections: Adjusts the detector response to account for electronic processing dead time.
- 5. Window definition using energy ranges: The extension uses energy based windows (rather than older index based windows), consistent with IAEA recommendations to define radioelement windows in energy terms.
- 6. Stripping (Compton stripping): Applies stripping ratios to isolate K, U and Th contributions from overlapping spectral responses.
- 7. Elemental concentrations: Converts corrected counts into potassium (%K), equivalent uranium (eU) and equivalent thorium (eTh).
- 8. Ratios and ternary images: Produces derived products commonly used for interpretation and mapping.
This transparent, step-by-step process demystifies radiometric processing and gives you full control.
Radiometric workflow and stripping step in Oasis montaj 2025.2
NASVD smoothing for cleaner, more interpretable spectra
Noise can obscure real geology, a common challenge with high-channel detectors or drone systems. The Radiometrics Extension integrates Noise-Adjusted Singular Value Decomposition (NASVD) directly into the workflow to distinguish the geological ‘signal’ from random ‘noise’. The result is a cleaner, more stable spectrum that dramatically improves the quality of final map products.
Here’s what makes the NASVD implementation in Oasis montaj so powerful:
- Integrated directly into the workflow: NASVD isn’t an add‑on step, it sits naturally within the radiometric correction sequence.
- Clear control over eigenvector selection: The interface follows best practice: showing contribution levels, hiding cosmic components automatically, and presenting a sensible default eigenvector range.
- Designed for modern sensors: NASVD supports high‑resolution spectra collected during airborne and drone‑borne mapping, helping distinguish coherent geological signal from statistical variation prior to downstream processing.
- Helpful for both airborne and drone datasets: Gamma‑ray spectra collected with compact, lightweight detectors commonly used on drones are inherently noisier due to counting statistics, making spectral stabilisation an important step before stripping and concentration calculations in mapping workflows.
- Non‑blocking: The smoothing process runs in the background, so users can continue exploring or visualising their data without interruption.
The result is a cleaner, more stable spectrum that dramatically improves the quality of stripping, concentration calculations, and final map products.
Effect of NASVD smoothing on radiometric data
Built for specialists and occasional users alike
Many geoscientists don’t work with radiometric data every day. We designed the workflow to be easy to revisit, with an obvious order of operations and clear parameter dialogs that reduce the chance of errors. For power users, every tool is scriptable, making it simple to apply consistent workflows across large surveys or build repeatable processes for clients.
The new workflow layout, parameter panels, and modeless tools give radiometric users more confidence throughout the process.
Where radiometric data makes a difference
Radiometric ternary map (K–U–Th) in Oasis montaj 2025.2
A clearer radiometric workflow supports a wide range of applications:
- Mineral exploration: Detect alteration zones, map lithological boundaries, and combine radiometric with magnetic and gravity data for context.
- Drone-based surveys: Ideal for tailings, small sites, or areas unsuitable for ground crews.
- Environmental assessments: Map contamination, investigate floodplains, or characterise soils.
- Agriculture and soil mapping: Radiometric “fingerprints” help estimate soil texture and inform land management decisions.
Commitment to continuous innovation
This milestone is just the beginning. Our partnership with Medusa Radiometrics is a long-term commitment to the radiometric community, and our focus is already on the future: enhancing spectral analysis and integrating data more deeply into the entire geophysical workflow. We’re dedicated to ensuring Oasis montaj not only meets but anticipates the evolving needs of geoscientists.
Get started
The Radiometrics Extension is available in Oasis montaj 2025.2. Maintained users of the 256-channel or Praga Radiometric Processing extensions will receive it automatically.
Exclusive offer for Medusa Radiometrics customers
Under our partnership, all purchasers of Medusa Radiometrics instruments receive a free one-year subscription to the Radiometrics Extension (Oasis montaj base subscription required).
If you work with radiometric data, the new workflow delivers a more reliable, consistent, and approachable way to achieve credible results from modern survey datasets.