What is a spectrometers F-number?

May 25, 2017 | Glossary of Spectroscopy Terms, Optics, Spectrograph

The f-number, also called the f-stop or the f-ratio, is an optical component’s focal length divided by its diameter: where N is the f-number, ƒ is the focal length, and D is the diameter. Often, this is written as “f/N,” so for N=4, it is written “f/4.” This number...

What is a Popping Pixel?

May 25, 2017 | Detectors, Glossary of Spectroscopy Terms

Popping pixels in spectrometers have a dark current that changes abruptly, likely due to defects in the pixel. It is the most disruptive type of defective pixel because it is unpredictable. There is no way to account for the behavior, so a popping pixel must always be...

What is a Dead Pixel?

May 25, 2017 | Detectors, Glossary of Spectroscopy Terms

Dead pixels in spectrometers have significantly lower responses than nearby pixels. If pixels are merely weak instead of completely dead, they can be accounted for in the system sensitivity curve. However, this will decrease S/N. If this becomes a problem, the dead...

What is a Defective Pixel?

May 25, 2017 | Detectors, Glossary of Spectroscopy Terms

A defective pixel in a spectrometer is a pixel that doesn’t behave as it should to the point of being unusable. This includes dead pixels, hot pixels, and popping pixels. The SpectraWiz software can account for defective pixels and will interpolate a value...

What is Exposure Time?

May 25, 2017 | Glossary of Spectroscopy Terms, StellarNet Definition

The exposure time is the amount of time that the detector is exposed to light. This is related to the integration time, which is the amount of time the detector keeps electrons trapped in the pixel wells before reading them. If the detector has a shutter, the exposure...

What is a Dynamic Range?

May 25, 2017 | Glossary of Spectroscopy Terms, Uncategorized

The dynamic range of a spectrometer is a measure of the intensity resolution of a spectrometer. In essence, it is the maximum signal before saturation over the minimum signal, where the minimum signal is a signal equal to the baseline noise (S/N = 1). However, the...