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Gaussmeter Probes for FH 35, FH 36, FH 37
Gaussmeter Probe Selection
- Choose a probe to match the application. Do not buy more accuracy, field range, or fragility than is actually necessary.
- The thinner a probe, the more fragile it is. Try to avoid the temptation to select an easily damaged probe based on a possible, but not probable,future application. For instance, avoid using an exposed-device probe such as a Model MFT-3E03 type for general field measurements.
Once a stem or sensor has been damaged, the probe is not repairable. - Metal enclosed probes, such as the Model MMT-6J08 and MMA-2508 types, offer the greatest amount of protection to the Hall sensor, and therefore are the most rugged types.
- Be cautious about using aluminum stemmed, transverse probes, such as the Model MMT-6J08 type, where AC magnetic fields are to be measured. Eddy currents in the stem material can affect reading accuracy. A superior choice for AC measurements would be the Model MNT-4E04 type fiberglass-epoxy stem probes.
- Several stem lengths are offered for each probe type. User preferences or test set-up dimensions usually determine the final selection. Longer stems are more susceptible to accidental bending (in many cases not catastrophic, but bothersome). Stem length does not affect performance.
- Be aware of the differences in the probe "active areas" shown on the data sheet. A Hall effect probe will indicate the average field value sensed over that total active area. Thus, when measuring magnetic fields with a high gradient across the sensor width, choose the smallest active area practical (keeping in mind, however, the fragility rule in number 2 above).
- The gaussmeter probes exhibit different ranges of magnetic fields over which they will provide valid readings. Check the specification sheet for these usable ranges. High Stability probes, such as those whose model numbers end in -VG, are usable on full scale ranges of 300 gauss (30 millitesla) to 30 kilogauss (3 tesla). The High Sensitivity family of probes (i.e., -VH models) can be used on 30 G (3 mT) to 30 kG (3 T) full scale ranges. High field probes are specially calibrated to provide use above 30 kG (3 T), and the new "Gamma" probe operates on the 300 mG (30 µT) and 3 G (300 µT) ranges.
- If none of the standard probe configurations seem to fit your needs, always remember that we can provide custom probes to meet your physical, temperature, and accuracy requirements.
Polarity on Transverse Probes
The output will be positive when the direction of the flux density vector is into the logo (i.e., the logo is towards the north pole)
The output will be positive when the direction of the flux density vector is into the logo (i.e., the logo is towards the north pole)
Definitions
| A | = | Distance from tip of probe to center line of active area. |
| +B | = | Magnetic flux density vector (positive Gaussmeter reading). |
| HST | = | High Stability Probe. |
| HSE | = | High Sensitivity Probe. |
| UHS | = | Ultra-High Sensitivity Probe. |
| Type | HST-1 | HST-2 | HSE-1 | UHS-1 |
| Usable on ranges | 300 G | 300 G | 30 G | 300 mG |
| 3 kG | 3 kG | 300 G | 3 G | |
| 30 kG | 30 kG | 3 kG | 30 G | |
| 300 kG | - | 30 kG | - |
Radiation Effects on Gaussmeter Probes
The HST and HSE probes use a highly doped indium arsenide active material. The HST material is the more highly doped of the two and therefore will be less affected by radiation. Some general information relating to highly doped indium arsenide Hall generators is as follows:- Gamma radiation seems to have little effect on the Hall generators
- Proton radiation up to 10 Mrad causes sensitivity changes less than 0.5 %
- Neutron cumulative radiation (> 0.1 MeV, 10E15sq.cm) can cause a 3 to 5 % decrease in sensitivity
- In all cases the radiation effects seems to saturate and diminish with length of time exposed
Axial Probes for FH 35, FH 36, FH 37
| Model No. | L | D | A | Active Area | Stem Material | Freq. range |
Type | Corrected accuracy (% of reading) |
Op. temp. range |
Temperature coefficient (max) |
|
| Zero | Calibration | ||||||||||
| MMA-0602-TH | 2 ±0.125" | 0.060 dia +0.001 -0.003" |
0.010 ±0.005" | 0.020" dia (approx) |
Aluminium | DC and 10 to 400 Hz | HST-2 | ±0.25% to 10 kG | 0 ºC to +75 ºC | ±0.13 G/ºC | ±0.01%/ºC |
| MMA-0604-TH | 4 ±0.125" | ||||||||||
| MMA-0608-TH | 8 ±0.125" | ||||||||||
| MMA-0618-TH | 18 ±0.25" | ||||||||||
| MMA-1302-UH | 2 ±0.125" | 0.125 dia ±0.005" | Stainless steel | DC and 10 to 100 Hz | ±0.25% to 20 kG | ||||||
| MMA-1304-UH | 4 ±0.125" | ||||||||||
| MMA-1308-UH | 8 ±0.125" | ||||||||||
| MNA-1902-VH | 2 ±0.125" | 0.187 dia ±0.005" | 0.030" dia (approx) | Fiberglass epoxy | DC and 10 to 400 Hz | HSE-1 | ±0.25% to 30 kG | ±0.09 G/ºC | FH36: -0.015%/ºC FH35: -0.04%/ºC |
||
| MNA-1904-VH | 4 ±0.125" | ||||||||||
| MNA-1908-VH | 8 ±0.125" | ||||||||||
| MMA-2502-VH | 2 ±0.063" | 0.25" ±0.006" | Aluminium | ||||||||
| MMA-2508-VH | 8 ±0.125" | ||||||||||
| MNA-1902-VG | 2 ±0.125" | 0.187" dia ±0.005" | Fiberglass epoxy | HST-2 | ±0.15% to 30 kG | ±0.13 G/ºC | ±0.005%/ºC | ||||
| MNA-1904-VG | 4 ±0.125" | ||||||||||
| MNA-1908-VG | 8 ±0.125" | ||||||||||
| MMA-2502-VG | 2 ±0.063" | 0.25" ±0.006" | Aluminium | ||||||||
| MMA-2508-VG | 8 ±0.125" | ||||||||||
| MMA-2536-WL | 36 ±0.25" | DC | HST-1 | ±1% to 100 kG | |||||||
| MCA-2560-WN | 60 ±0.50" | 0.025 ±0.005" | Stainless steel | ±2% to 100 kG | 1.5 K to 350 K | ±0.01%/ºC | |||||
Flexible Transverse Probes for FH 35, FH 36, FH 37
This table is for L = 3 inches and S = 0.375 inches
| Model No. | W | T | A | Active Area | Stem Material | Freq. range |
Type | Corrected accuracy (% of RDG) |
Op. temp. range |
Temperature coefficient (max) |
|
| Zero | Calibration | ||||||||||
| MFT-3E03-VH | 0.135" max | 0.025" max | 0.125" ±0.005" | 0.040" dia (approx) | Flexible tubing | DC and 10 to 400 Hz | HSE-1 | ±0.25% to 30 kG | 0 ºC to +75 ºC | ±0.09 G/ºC | FH36: -0.015%/ºC FH35: -0.04%/ºC |
| MFT-3E03-VG | HST-1 | ±0.15% to 30 kG | ±0.13 G/ºC | ±0.005%/ºC | |||||||
| MFT-2903-VJ | 0.085" max | 0.020" max | 0.065" ±0.005" | 0.030" dia (approx) | HSE-1 | ±0.50% to 30 kG | ±0.09 G/ºC | FH36: -0.015%/ºC FH35: -0.04%/ºC |
|||
| MFT-2903-VH | HST-2 | ±0.25% to 30 kG | ±0.13 G/ºC | ±0.005%/ºC | |||||||
This table is for L = 15 inches and S = 0.75 inches
| Model No. | W | T | A | Active Area | Stem Material | Freq. range |
Type | Corrected accuracy (% of RDG) |
Op. temp. range |
Temperature coefficient (max) |
|
| Zero | Calibration | ||||||||||
| MFT-4F15-VH | 0.150" max | 0.045" max | 0.150" ±0.005" | 0.040" dia (approx) | Flexible tubing & epoxy fiberglass | DC and 10 to 400 Hz | HSE-1 | ±0.25% to 30 kG | 0 ºC to +75 ºC | ±0.09 G/ºC | FH36: -0.015%/ºC FH35: -0.04%/ºC |
| MFT-4F15-VG | HST-2 | ±0.15% to 30 kG | ±0.13 G/ºC | ±0.005%/ºC | |||||||
Transverse Probes for FH 35, FH 36, FH 37
range
accuracy
(% of reading)
temp.
range
coefficient (max)
to
+75 ºC
FH35: -0.04%/ºC
10 to
400 Hz
10 to
400 Hz
350 K
Gamma Probes for FH 35, FH 36, FH 37
Application is optimum when fields are homogeneous over length >1 foot. The active sensing length of the gamma probe is -3.125 inches.
| Model No. | W | T | A | L | Freq. range |
Type | Corrected accuracy (% of reading) |
Op. temp. range |
Temperature coefficient (max) |
|
| Zero | Calibration | |||||||||
| MLA-5006-HJ | 0.25" | 0.5" | 2.2" | 5.7" | DC and 10 to 400 Hz | UHS-1 | ±0.5% to 2 gauss | 0 ºC to +75 ºC | 1 mG/ºC | FH36: -0.02%/ºC FH35: -0.05%/ºC |
| MLA-5009-HJ | 4.5" | 9.0" | ||||||||
2-Axis Probes for FH 37
range
(% of reading)
coefficient (max)
0.5% from 20 to 30 kG
3-Axis Probes for FH 37
range
(% of reading)
0.5% from 20 to 30 kG