Harsh Environment Sensors

Physics of Survival: High-Temperature Electronics

The primary failure mode for sensors in extreme heat is not the sensing element itself, but the signal conditioning electronics and the packaging. Standard P-N junction semiconductors experience excessive leakage current above 150°C, rendering the output signal useless. AIMRSE combats this by utilizing Silicon-on-Insulator (SOI) technology. By isolating the active silicon device from the substrate with a dielectric layer (silicon dioxide), we eliminate latch-up and reduce leakage currents by orders of magnitude, enabling stable operation up to 300°C continuously.

Mechanically, the challenge involves "creep"—the slow deformation of materials under constant stress and temperature. In pressure transducers, bonded foil strain gauges utilize organic epoxy adhesives that soften at high temperatures, causing "zero drift." AIMRSE replaces these with Sputtered Thin Film technology. We deposit the resistive bridge directly onto the stainless steel diaphragm using molecular sputtering in a vacuum chamber. This creates an atomic bond with zero creep, zero glue lines, and exceptional long-term stability (typically < 0.1% drift/year), even under severe vibration and thermal shock.

Fig.1 Atomic Bonding: A sputtered thin-film Wheatstone bridge deposited directly onto the sensing diaphragm eliminates the hysteresis caused by epoxy adhesives in traditional sensors.

Position Sensing: The Hermetic LVDT

In subsea valve actuation or hydraulic cylinder feedback, determining the precise position of a moving part is critical. Potentiometers wear out; magnetostrictive probes have pressure limitations. AIMRSE advocates for the Linear Variable Differential Transformer (LVDT). This is a non-contact inductive device with infinite resolution and, theoretically, infinite life.

Our Harsh Environment LVDTs are constructed with the coil assembly fully encapsulated in a laser-welded stainless steel or Inconel housing. The core (the moving part) floats inside the bore tube, measuring position via magnetic flux coupling without any physical contact or friction. This design is pressure-balanced or fully hermetic up to 20,000 PSI, making it impervious to seawater ingress. We utilize high-temperature magnet wire and potting compounds to prevent coil shorting even when subjected to ambient pressures of deep-sea trenches.

Fig.2 Non-Contact Reliability: The LVDT allows for position measurement through solid metal walls using magnetic induction, eliminating the need for dynamic seals that can leak.

Chemical Analysis in the "Danger Zone"

Measuring pH or Conductivity in a lab beaker is simple. Measuring it at 150°C and 5,000 PSI in a geothermal brine is an engineering feat. The weak point in standard pH probes is the "Reference Electrode"—a liquid junction that must interact with the process fluid. Under high pressure, process fluid forces its way *into* the sensor, poisoning the reference gel and causing drift.

AIMRSE HPHT Chemical Sensors utilize a Double-Junction, Pressurized Reference System. We pressurize the internal electrolyte gel to match or slightly exceed the process pressure, preventing ingress (poisoning). Furthermore, we replace fragile glass bulbs with ruggedized, hemispherical glass or solid-state ISFET (Ion-Sensitive Field Effect Transistor) chips for extreme mechanical robustness. Our conductivity sensors use 4-electrode contacting technology or toroidal (inductive) non-contact methods to measure aggressive acids without electrode polarization or fouling.

Sensor Portfolio Specifications

We offer a comprehensive range of transducers tailored for the Upstream Oil & Gas, Aerospace Propulsion, and Industrial Metrology sectors.

Fig.3 Validated Accuracy: Automated calibration stations verify non-linearity, hysteresis, and thermal shift across the entire compensated temperature range (CTR) before shipment.