Monochromators thermal problems

Thermal problems of monochromators in the most intense SR beams and possible solutions... 

Atomic emission spectroscopy can be employed, generally with an inductively coupled plasma for thermal excitation. The sample is introduced into the plasma as a mist of ultrafine droplets, and the monochromator and detector are set to measure the intensity of an atomic emission line characteristic of the element. This technique is powerful, general, sensitive, linear, and able to measure over 70 elements, and, as a result, is widely used. Response is typically linear over four orders of magnitude in concentration with relative standard deviations of 1 to 3%. In low-salt aqueous solutions, detection limits range from 10 to 1000 nanomolar without preconcentration. Significant problems with saline samples remain, but use of Babington nebulizers alleviates these problems somewhat. 

The instruments built with AOTFs as monochromators are often connected to fiber optics to obviate problems with polarized light. The instruments are also always designed in such a manner as to stabilize the crystal thermally, as the wavelength emitted per frequency applied is quite temperature sensitive. 

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