Time of flight

This information can then be used to measure velocity or path length, or as a way to learn about the particle or medium's properties (such as composition or flow rate).

The traveling object may be detected directly (direct time of flight, dToF, e.g., via an ion detector in mass spectrometry) or indirectly (indirect time of flight, iToF, e.g., by light scattered from an object in laser doppler velocimetry).

Time of flight technology has found valuable applications in the monitoring and characterization of material and biomaterials, hydrogels included.

[1][2] In electronics, one of the earliest devices using the principle are ultrasonic distance-measuring devices, which emit an ultrasonic pulse and are able to measure the distance to a solid object based on the time taken for the wave to bounce back to the emitter.

Originally, it was designed for measurement of low-conductive thin films, later adjusted for common semiconductors.

In this method, blood entering the imaged area is not yet saturated, giving it a much higher signal when using short echo time and flow compensation.

An ultrasonic flow meter measures the velocity of a liquid or gas through a pipe using acoustic sensors.

Open channel flow meters measure upstream levels in front of flumes or weirs.

Optical time-of-flight sensors consist of two light beams projected into the fluid whose detection is either interrupted or instigated by the passage of small particles (which are assumed to be following the flow).

This is not dissimilar from the optical beams used as safety devices in motorized garage doors or as triggers in alarm systems.

Since the location of the beams is relatively easy to determine, the precision of the measurement depends primarily on how small the setup can be made.

For such a sensor to provide valid data, it must be small relative to the scale of the flow and the seeding density.

MOEMS approaches yield extremely small packages, making such sensors applicable in a variety of situations.

High frequencies are passively shielded and damped by radar absorbent material.

In this way the tube can be configured to act as a weak achromatic quadrupole lens with an aperture with a grid and a delay line detector in the diffraction plane to do angle resolved measurements.

The sample should be immersed into the tube with holes and apertures for and against stray light to do magnetic experiments and to control the electrons from their start.

Laser-based time-of-flight cameras are part of a broader class of scannerless LIDAR, in which the entire scene is captured with each laser pulse, as opposed to point-by-point with a laser beam such as in scanning LIDAR systems.