MVLscope

TINY WORLD / X-RAY CLUES

Element Detective

CASE 1 OF 3

The copper clue

Three particles look alike. Which one has copper signals?

SIMULATED EDS · 20 kV

Choose where to look

0 spectra
Invented specimen · no physical scale
Tap A, B or C.

The image gives no element labels. The X-rays are your clues.

Your X-ray clues

Choose a spot.
Scan its X-ray clues.

Selected K families · approximate relative strengths

Start here: choose any particle, then scan it.

Your reference cards

Compare positions and relative strengths

Which particle has copper signals?

Scan at least two particles before choosing.

Optional scientific referencesExplore SEM/FIB ↗

Preparing your case…

YOUR FIRST DISCOVERY

Let the peaks tell you.

EDS means energy-dispersive X-ray spectroscopy. Different elements can produce characteristic X-ray peaks: their positions are your clues.

  1. Choose a labelled spot on the specimen.
  2. Press Scan this spot to collect a spectrum.
  3. Compare the peak positions with the reference cards, then choose the conclusion your evidence supports.

You can revisit spectra, change your answer and try again. “Describe” gives a text alternative. There is no timer or penalty.

How does the selected spot become an X-ray clue?

Source → specimen → detector

An electron beam reaches a small region of the specimen. The interaction can produce characteristic X-rays. An EDS detector sorts detected X-ray events by energy to build the spectrum you compare in this activity.

Illustrative cutaway of an electron microscope, specimen chamber and side-mounted EDS detector.
Illustrative apparatus only. The cutaway and arrows explain a connection; they are not individual electron trajectories, X-ray collection angles, or a specimen depth model.

Optional interactive diagram. The activity keeps your evidence.

Choose a spot in the activity.

  1. 1 · Electron columnThe activity holds the virtual beam at 20 kV. The mint guide connects the source to the specimen.
  2. 2 · Selected spotA region can contribute X-rays, including more than one material at a boundary. This marker is not an interaction-volume calculation.
  3. 3 · EDS detectorThe gold guide connects the sampled region to the detector. Use your captured spectrum and reference cards for element clues.

The equipment illustration has no element identities or measurements. Your original specimen image, spectra and evidence checks remain the activity's scientific record.

Read JEOL's explanation of EDS detection ↗

ABOUT THIS SIMULATION

Real ideas. Invented specimens.

EDS uses characteristic X-ray energies to help identify elements. These original teaching specimens and spectra show selected K lines at approximate reference energies. Selected K-family relative strengths follow approximate summed-line values in the LBNL X-ray Data Booklet (Table 1-3). Each family is collapsed into one peak with the same illustrative 130 eV width, so its area ratio equals its peak-height ratio. Overall signal and count variations are illustrative. Energy-dependent detector efficiency and broadening, absorption and matrix effects are omitted; these heights are not concentration measurements. They are not measured composition percentages.

The virtual beam is held at 20 kV. A fixed 0.13 keV full width at half maximum (FWHM) is a teaching approximation, not a detector calibration. Several lines, background effects and possible interferences are omitted. A spot samples a region: the boundary case uses a simple spatial average, not an electron-transport calculation or a depth reconstruction.

The narrow view in case 3 is a crop of the same captured spectrum. The wider view reveals additional energies; it does not improve energy resolution. Two signals together do not prove an alloy, compound or three-dimensional structure. A missing visible peak does not prove that an element is absent.

The scan animation is shortened for play; it does not represent instrument acquisition time. Your cases last while this page is open. New mysteries and reloading clear the evidence. Descriptions are optional without penalty. This is a learning game, not a secure assessment, operating procedure or real material identification service.

Scientific background and model notes

Open a fresh set of cases?

This clears the spectra and progress from your current cases.