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Fiber Optic Temperature Probes
Fiber Optic Temperature Probes Selection Guide
The following is the list of probes used in the markets that BioTemp4Life sells. Others are available upon request.
Please use this list to select which product you need.
| Part Number | Model Number | Calibrated Accuracy | Standard Length Other lengths available please specify in meter | Minimum Temperature | Maximum Temperautre | Tip Diameter | Immersion Time Response | Tip Location from end | Minimum Bend Radius | Material | Probes compatible with these Temperature Transmitters | Datasheet |
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| FGA-0014A | PRB-100-02M-STM | (10° C to 60 °C) +/- 0.10° C | 2 | -40°C | 100° C | 1500 µm | 1.5s | 1-2 mm | 15 mm | Nylon | HTX, FTX |  |
| FGA-0193A | PRB-500-2M-STM-MRI | (10° C to 60 °C) +/- 0.10° C | 2 | -40°C | 100° C | 1000µm | 0.6s | 1-2 mm | 10 mm | Nylon | HTX, FTX | |
| FGA-0213B | PRB-242-2M-STM-MRI | (20° C to 60 °C) +/- 0.10° C | 2 | -40°C | 150°C | 500µm | 180ms | 1 mm | 16mm | ETFE | FTX-X00-LUX+-Cryo | |
| FGA-0213B | PRB-242-02M-STM-CRYO | (20° C to 60 °C) +/- 0.10° C | 2 | -200°C | 150°C | 500µm | 180ms | 1 mm | 16mm | ETFE | FTX-X00-LUX+-Cryo | |
| FGA-0214A | PRB-140-2M-STM-MRI | (20° C to 60 °C) +/- 0.10° C | 2 | -40°C | 150°C | 250µm | 150ms | Tip at end | 6mm | ETFE | FTX-HG | |
| FGA-0170B | PRB-420-0.1M-HFBR-MRI | (10° C to 60 °C) +/- 0.15° C | 0.1 | -40°C | 150°C | 700µm | 0.25s | Tip at end | 50mm | Polyimide & ETFE | FTX | |
| FGA-0010A | PRB-G40-2.0M-ST-C | +/- 1.0 °C | 2 | -40°C | 250°C | 650µm | 250ms | 1-2 mm | 60mm | Polymide tip, PTFE tubing | FTX | |
| FGA-0060A | PRB-G40-2.0M-ST-HC | +/- 2.0 °C | 2 | -40°C | 350°C | 650µm | 250ms | 1-2 mm | 60mm | Polymide tip, PTFE tubing | FTX | |
| FGA-0009A | PRB-G40-2.0M-STM-MRI | (10° C to 60 °C) +/- 0.10° C | 2 | -40°C | 120°C | 750µm | 250ms | 1-2 mm | 50 mm | Polymide tip, PTFE tubing | FTX, HTX-MRI | |
| FGA-0039A | PRB-G20-2.0M-ST-C | +/- 1.0 °C | 2 | -40°C | 250°C | 450µm | 200ms | 1-1.5mm | 30mm | Polymide tip, PTFE tubing | FTX | |
| FGA-0061A | PRB-G20-2.0M-ST-HC | +/- 2.0 °C | 2 | -40°C | 350°C | 450µm | 200ms | 1-1.5mm | 30 mm | Polymide tip, PTFE tubing | FTX | |
| FGA-0008A | PRB-G20-2.0M-ST-MRI | (10° C to 60 °C) +/- 0.10° C | 2 | -40°C | 120°C | 305µm | 250ms | 1-1.5mm | 30 mm | Polymide tip, PTFE tubing | FTX, HTX-MRI | |
| FGA-0062A | PRB-GB3-2m_ST-L | ± 1.0°C | 2 m | -40°C | 200°C | 2.3mm | 2sec | N/A | 8 mm | FEP | FTX-300-LUX+ / HTX-100-PWR / FTX-XXX-PWR+ | |
| FGA-TBD | PRB-422-35M-STM-L | TBD | 1-35M | -40°C | 150°C | 900 µm | Not rated | 50mm | Black Tefzel jacket with 0.45mm glass fiber core | FTX-HG | ||
| FGA-0173A | PRB-1000-0.35M-ST-HT | 350°C to 750°C +/-0.5°C | 0.35M | 0°C | 750°C | 5mm | 30 seconds | Solid-Does not bend | Polyimide and Alumina | FTX-300-LUX+HT, FTX-200-LUX+HT, FTX-100-LUX+HT | |
When Specifying a probe, you need the model number, length and connector type:
Other connectors available upon request Please specify any additional tubing over probe for special applications
- Customers may specify specific labeling for probes.
- Probes may are labelled by serial number and part number
- Probes can be labelled with offsets if required.
- Offsets may change at yearly calibration or if probe is repaired
The following is a comparison of the fiber used to make probes and a few basic probe specifications for outside diameter and Immersion Time Constant.
The above picture shows actual photographs of the fiber embed in a case that compares the fiber used to make probes with a few basic probe specifications, including outside diameter and Immersion Time Constant.
Immersion Time Constant or Tao
What Is Thermal Time Constant?
The thermal time constant (often symbolized as τ) is the time it takes for a temperature sensor to respond to 63.2% of a sudden temperature change.
Conceptually:
- If the ambient temperature suddenly changes from T₁ to T₂,
- The sensor output will reach T₁ + 0.632×(T₂ − T₁) after time τ.
This comes from the exponential behavior of heat transfer:
Why It Matters in Fiber Optic Temperature Sensors
Fiber optic sensors, such as OSENSA’s work in fast-changing environments (e.g., transformers, medical ablation, RF heating, etc.). In these cases:
- A low thermal time constant = fast response, which is crucial for detecting rapid thermal transients.
- A high TTC would miss or smooth out fast changes, leading to inaccurate readings.
Trade-offs
| Design Factor | Effect on Time Constant |
| Smaller thermal mass | Faster (lower τ) |
| Direct fiber exposure | Faster |
| Protective sheathing | Slower (but more robust) |
| Good thermal conductivity | Faster |
| Low heat transfer (e.g., air) | Slower |
Correct Understanding:
- The time constant does not indicate full temperature change.
- It is the time needed to reach 63.2% of the total change.
Exponential Rule of Thumb:
- After 1τ → 63.2% of the change
- After 2τ → ~86.5%
- After 3τ → ~95%
- After 5τ → ~99.3% (effectively complete)
So, the full response takes multiple time constants (like 5x the thermal time constant), not just one.
Why This Matters:
Why This Matters:
- Underestimating the actual time to stabilize can lead to false assumptions about sensor performance and response accuracy, especially in fast-changing or safety-critical systems.