Optical Spectroscopy System

view 1Basic Operation: Light is directed by the optical fibers to the entrance slit of the spectrograph. The light is then collected by the collimating mirror and reflected into a grating, where it is dispersed into individual wavelengths. The diffracted light is reflected by a focusing mirror to the CCD detector. Since each wavelength leaves the grating at a different angle, each has a different horizontal position when the light reaches the detector. The CCD detector then simultaneously measures the intensity of each individual wavelength and generates a spectrum based upon those intensity readings.

spectrum

view 2Equipment Specifications:

  • Acton Research Spectrapro 300i imaging Czerny-Turner spectrograph with a micrometer controlled entrance slit, 300 mm focal length, and an operating range from 185 nm to the far infrared. Also includes a triple grating turret with 300,600, and 1200 g/mm gratings.
  • Princeton Instruments SpectruMM CCD Detection system with Hamamatsu 1024X256 front illuminated detector.
  • Detector interfaced with PC using PCI card. Spectrasense operating software used to collect and analyze data.

view 3Performance Capabilities:

  • Operating Range is 185 nm to 1400 nm with best results in the visible range.
  • Resolution of .1 nm using 1200 g/mm grating.
  • Four leg fiber optic bundle allows monitoring of four light sources simultaneously.

Applications:

  • High resolution imaging capabilities could be used to identify species present in plasmas and determine their properties through emission spectra.
  • Further research possibilities include the measurement of electron temperature from band intensity.

For further details about calibration and operation of the spectroscopy system, consult the Spectrometer Operating Procedure.