Diagnostics for the DEC Train
You cannot tune or trust a converter you cannot measure; the train is instrumented to see beam, conversion, and losses in real time.
Measuring an energy cascade
Because the DEC train's efficiency is a cascade of handoffs, diagnostics must watch the energy at each stage — what enters, what is converted, and what is lost. These measurements do two jobs: they feed the real-time control loop that keeps stages matched, and they close the efficiency budget so operators know where energy is going.
What is measured
- Beam energy spectrum entering the converter — sets the TWDEC and collector tuning.
- Beam and stage currents — track charge flow and interception.
- Plasma conductivity and flow in the MHD channel.
- Surface temperatures on grids and thermionic emitters — heat load and safety.
- Bus voltage and power — the delivered output that closes the budget.
- Vacuum pressure and high-voltage health — breakdown precursors.
From data to decisions
The diagnostics feed both the control system and the operators. In real time, they let the controller re-match stages as the beam drifts. Over longer periods, they reveal trends — rising interception, creeping erosion, a drifting spectrum — that inform maintenance and design refinement. Without them, the recovery fraction would be an assumption rather than a measured quantity.
Role in the test program
For a design-stage machine, diagnostics are not a convenience but the point: the ~2032 burner test unit exists largely to measure what has so far been modeled. A well-instrumented DEC train is how the program will confirm or correct the efficiency budget and validate the direct-conversion strategy on a real D-3He plasma.