FAQ

Troubleshooting and FAQ

This chapter covers common issues and how to resolve them. If your issue is not listed here, contact Medusa support — the system log files (available under Settings → System → Maintenance) may help diagnose the problem.

Connection Issues

I cannot reach the interface in my browser

Check the following:

You are using the correct IP address for your connection type (192.168.3.1 for WiFi, 192.168.2.150 for direct Ethernet)
If connecting via Ethernet directly to a computer, the computer's network adapter must be set to a fixed IP address in the 192.168.2.x range
If connecting via a router, the detector's IP address may have changed — use the Detector Finder tool or try the hostname (e.g. MS-2000-0054.local)
Try using the hostname instead of the IP address, or vice versa

The interface does not load on my phone or tablet

Turn off your mobile data connection. When both WiFi and mobile data are active, the phone may route traffic over the cellular network instead of the WiFi connection to the detector.

The Detector Finder tool does not show my detector

Make sure your computer is on the same network as the detector. If the detector is connected via Ethernet to a router, your computer must also be connected to that router. If the detector is connected directly to your computer via Ethernet, use the default IP address 192.168.2.150 instead.

GPS Issues

The GPS shows "No antenna"

The GPS antenna is not connected or is not detected. Check the antenna connector on the detector.

The GPS is acquiring but takes a long time to get a fix

A cold start (first fix after the detector has not been used for a while) can take several minutes. Make sure you have a clear view of the sky — indoor use will not yield a fix. You can monitor the number of satellites and accuracy on the Dashboard.

Spectrometer Issues

Stabilization takes a long time or does not complete

The spectrometer needs at least 10,000 counts in the 400–3,000 keV range to calculate a valid stabilization. In low-activity environments or with a small crystal, this may take longer than usual. Make sure the gain is set correctly under Settings → Sensors → Gamma.

The detector shows negative radionuclide concentrations

This is a known behaviour of Full Spectrum Analysis (FSA). FSA is a mathematical fitting method, and the best fit can sometimes result in a negative number for a nuclide — most commonly for ¹³⁷Cs in areas where no Cs is present. The average value will be close to zero, but individual data points fluctuate around it.

Negative concentrations can also occur when a single spectrum does not contain enough counts to accurately determine concentrations. This is more common with small crystals or short measurement intervals.

Solutions:

Increase Spectra to sum under Settings → Sensors → Spectral — this averages more spectra per data point, reducing uncertainty.
Switch the Fit mode to NNLS Full Spectrum Analysis — this constrains the fit to only include nuclides with a positive concentration.

Storage Issues

The SCN and AUX LEDs are blinking red

The storage has exceeded the configured warning threshold. Download and delete old projects to free up space. The threshold can be adjusted under Settings → System → Storage.

I cannot delete the active project

The active project cannot be deleted. To delete it, first create a new project (which immediately becomes active) or continue an existing project, then delete the old one.

The detector has stopped logging data

If Overwrite files when full is disabled and the storage is completely full, the detector stops logging and sends a notification. Delete one or more projects to free up space — logging resumes automatically and a notification confirms this.

Data Issues

My download is taking a long time

Large projects take time to compress. Keep the browser open until the download finishes. If concentrations are included, the detector first generates the CSV — progress is shown in the header.

Settings and Configuration

I restored factory defaults — what was reset?

All settings are reset to the factory defaults configured by Medusa before shipping. Project data is not affected.

The system time is wrong

Go to Settings → System → About and click Update system time. If the detector has an internet connection, the time is taken from an online time server. Otherwise, the time of the device you are using to access the interface is used.