REBCO Strain and Thermometry Interface
Distributed strain and temperature along the winding pack feed both the quench path and the twin's slow structural-fatigue model.
Dual-purpose sensing
REBCO tape is strain-sensitive: critical current degrades once mechanical strain exceeds an irreversible limit. On the burner's 26.49 T plug the Lorentz loads are severe — the reason the plug-coil is overstressed ~3–3.9× at the design bore. This interface measures the strain and temperature fields that both the fast protection path and the slow fatigue model consume.
Sensor set
- Fiber Bragg grating (FBG) arrays for distributed strain and temperature along the conductor.
- Resistance thermometers (RTD) at structural nodes and joints.
- Reference (unstrained) fibers for common-mode thermal rejection.
# separate strain from temperature in FBG shift
# d(lambda)/lambda = k_eps * eps + k_T * dT
eps = ( dlam_sensor/lam - k_T*dT_rtd ) / k_eps
if eps > eps_irrev[coil]: # approach to degradation limit
flag('rebco_strain_margin', coil, eps)Two consumers, two rates
| Consumer | Rate | Use |
|---|---|---|
| quench path | us-ms | hot-spot cross-check |
| twin fatigue | min-hr | cumulative load, lifetime |
The fast consumer is the quench-detection interface, which uses temperature as an independent quench confirmation. The slow consumer is the digital twin's thermomechanics module, which integrates strain cycles into a fatigue estimate feeding predictive maintenance.
Owner: sense-side L2 for timestamping and transport; the fast cross-check is mirrored to L1. Calibration is traceable per fiber, with drift tracked so the strain margin is never read through a stale gauge. Design-and-simulation targets, validated against the twin before commissioning.