OMG Optical Magnetic Gradiometer
OMG is a very high performance total field magnetometer and gradiometer with both high sensitivity and high bandwidth. It uses a special pulsed pump laser recently developed by Twinleaf to provide high atomic spin polarization and very low systematic error. The sensor has a very narrow axial dead zone that is difficult to encounter during typical magnetic survey. The sensor measures magnetic field using a frequency counter and can track very large changes in magnetic field. It recovers immediately from transient magnetic pulses. With its extraordinary dynamic range, it faithfully tracks very large signal variation while maintiaining its high sensitivity. Multiple sensors can be synchronized using synchronization units such as SYNC4 and SYNC7.
Features
- Magnetic field gradiometer
- Two total magnetic field sensors
- Gradiometer baseline: 2.3 cm (other baselines available)
- Sensor standoff from front surface: 5.6 mm
- Optically pumped alkali metal (rubidium)
- Sensitivity: <0.2 pT/Hz1/2
- Sample rate: 480 Hz (1 kHz, 4 kHz on request, but sensitivity suffers)
- Heading error: ±5 nT
- Narrow axial dead zones: <±7°
- Field range: 1–100 µT
- Slew rate: >1000 nT/ms
- Sensor volume: 1.6×3.6×13.6 cm
- Sensor mass: 100 g
- Control unit volume: 1.5×6×13 cm
- Control unit mass: 400 g
- System power consumption: 6 W (5V, 1.2A; can run from USB-C PD power source)
Interface
- USB-C
- 5 W capable port required.
- Serial data output
- RJ-45 8p8c connector: Power, LVDS Serial, LVDS Sync Clock
- Software support
- Getting Started
- OMG command reference
- Twinleaf I/O tools
- Scalar Gradiometer.exe (Compiled Windows Labview 2020); Requires support drivers: LV2020 64bit Runtime and NI VISA
Images
Operation
Plug it in, and wait for the sensor to warm up. The status light blinks according to the sensor status:
| Code | Color | Status |
|---|---|---|
| -3 | Red/Black | Hardware Error |
| -2 | Red/Black | Low Voltage |
| -1 | Red/Black | Error |
| 0 | White/Black | Idle/off |
| 1 | Red/White | Cell heating |
| 2 | Purple/Red | Pump locking |
| 3 | Yellow/Red | Probe locking |
| 4 | Blue/White | Lasers locked; no spin signal |
| 5 | Green/White | Operational |
The status code is also reported as the status byte in the data stream:
...
12 49983.918231 5.49238 5
13 49983.398123 5.91023 5
14 49983.718472 5.43982 5
...
In text mode, the first column is the sequence number that should be sequential; this is useful to make sure you aren't missing points. The second column is the total magnetic field in nanotesla. The third column is the total field gradient in nT/cm. The last column is the status code.
Ordering
OMG-200/2, inquire for price.