A precise calibration lamp is required to calibrate the spectrum by associating the effective wavelength to any point in the spectrum image. This is done with a Thorium-Argon (ThAr) lamp so that the result will provide a lot of spectral lines in each order. This will be used to associate the wavelength to each pixel position in the order (the calibration law in each order is modeled by a polynomial law).
When you first receive your calibration unit, the Thorium-Argon lamp is packed separately in a protective box. Make sure to keep the box and use it whenever you have to transport the calibration unit.Two other lamps are included in the calibration unit:
- A Tungsten (halogen incandescent) lamp. Software will correct each order blaze function using the smooth continuous spectrum of this tungsten lamp, which is close to a 2800K planck function.
- Several LED lamps which, when used with the Tungsten lamp, will provide more light to the blue part of the spectrum to ensure each order is well defined during the geometry section of the processing.