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Spectra Measurement

VIS and NIR hyperspectral cameras

Wavelength ranges: VIS, NIR, SWIR

A strip in the camera’s field of view is illuminated and an imaging spectrograph produces sequentially high-resolution spectral and spatial images through its sensors. This technique is also known as push-broom technology. Figure 1 illustrates how it works.

How it works

  1. The remitted light of the illumiated strip is focused by a lens onto the entrance slit of the spectrometer.
  2. A mirror reflects the image from the slit onto the optical grating.
  3. The optical grating splits the light onto its wavelengths.
  4. A second mirror reflects the diffracted light from the grating onto an image sensor.
  5. The spectra of all points along the illuminated strip are imaged onto the sensor. The result is a two-dimensional image of the intensity over location and wavelength.

Technical points

Due to their significant effect on performance, some technical points are worth mentioning:

Short focal length, corrected NIR lenses:

large field of view

ZEISS optics & Offner spectrograph:

high-quality spectra

High-performance image sensor:

high spatial and spectral resolution, large dynamic range, high measurement repetition rate

Optimised electronics

measurement of extremely fast objects, high throughput

Figure 1: Principle of the Offner setup and data processing

Figure 2: Principle of our camera in operation

Multiplexed NIR spectrometer

Wavelength ranges: VIS/NIR/SWIR

A strip in the camera’s field of view is illuminated and sequentially imaged onto optical fibres arranged in a row. This technique is called push-broom technology. Figure 1 illustrates how it works.

How it works

  1. The remitted light of the illumiated strip is imaged onto a rotating mirror that reflects the light to a fibre cable for each location point.
  2. This mirror sequentially images the light of all optical fibres onto the entrance slit of the spectrometer and via filter onto an RGB sensor.
  3. The optical grating diffracts the light and images it onto a line sensor.
  4. The location points are then measured one after the other.

Technical points

Due to their significant effect on performance, some technical points are worth mentioning:

Independent optical fibres:

simultaneous measurement on multiple conveyors

ZEISS optics:

high spectral resolution, high measurement sensitivity

Figure 1: Beam path in multiplexer

RGB colour line scan camera

Wavelength ranges: VIS

A strip in the camera’s field of view is illuminated and sequentially measured at a high frame rate. This technique is called push-broom technology. The beam path is shown in Figure 1 to illustrate how it works.

How it works

  1. The remitted light of the illumiated strip is imaged onto a CMOS sensor with a colour filter in a Bayer pattern applied to it.
  2. The RGB information can be read out directly from the sensor.

Technical points

Due to their significant effect on performance, some technical points are worth mentioning:

Optimised electronics:

measurement of extremely fast objects, high throughput

CMOS sensor & ZEISS optics:

high image contrast, low noise

Figure 1: Principle of camera in operation mode

X-ray fluorescence spectrometer

Wavelength ranges: X-ray/UV

A strip in the detector’s field of view is illuminated and sequentially measured. This technique is also known as push-broom technology.

How it works

  1. The primary beam, emitted by an x-ray tube, excites the atoms in the irradiated material, which in turn emites fluorescence radiation.
  2. The resulting fluorescence is element-specific and measured by means of energy-dispersive detectors.
  3. The analysis of the spectra measured in this way allows to identify and determine the elemental composition of the material.

Technical points

Due to their significant effect on performance, some technical points are worth mentioning:

Water-cooled, high power x-ray tube:

high primary radiation intensity produces high fluorescence radiation intensity

Silicon drift detectors or the latest generation:

high count rates and best-possible energy resolution

Complete system (tube, detector & electronics:

fast and detailed identification of alloys, not only the main elements

Figure 1: Functionality of x-ray fluorescence analysis

Figure 2: Schematic diagram of our XRF spectrometer in operation
Figure 3: Generation of x-ray fluorescence radiation

Contact Us

Justus-von-Liebig
Straße 9/11
12489 Berlin
Germany

Phone:
+49 30 629 0790-0
Email:
mail@lla.de