# NLS-Glossary

Accelerometer

is a tool that measures proper acceleration. Proper acceleration is the acceleration of a body in its own instantaneous rest frame; this is different from coordinate acceleration, which is acceleration in a fixed coordinate system.

Acceptance angle

or the maximum acceptance angle is the largest possible light launch angle from the fiber axis. Light waves within the acceptance angle that enter the fiber become guided along the fiber core. If NA is the numerical aperture of a step index fiber, and light is launched from a medium of refractive index no, then maximum acceptance angle max is given by sinαmaxNAn0 Total acceptance angle is twice the maximum acceptance angle and is the total angle around the fiber axis within which all light rays can be launched into the fiber.

Acceptance cone

is a cone with its height aligned with the fiber axis and its apex angle twice the acceptance angle so that light rays within this cone can enter the fiber and then propagate along the fiber.

Acceptor atoms

are dopants that have one less valency than the host atom. They therefore accept electrons from the valence band (VB) and thereby create holes in the VB which leads to p > n and hence to a p-type semiconductor.

Accumulation Station

is a defined area of the roller conveyor system where the material to be conveyed is stopped.

Accuracy

The accuracy of a sensor is a measurement of the difference that can be expected between a sensor’s reading and the actual distance measured. The resolution is the smallest change in distance that a sensor can detect and is typically a smaller value than the accuracy error. Accuracy may be affected by Temperature stability , target reflectance or ambient light, Long-term stability and a statistical error (which can be removed by calculation)., which generally will not affect the resolution. For many applications, resolution is more important than absolute accuracy.

In general, laser sensor manufacturers may interchangeably use the terms Accuracy and Linearity, although Linearity is a term most often associated with analog measuring devices.