Edinburgh Instruments, Photonics Division, Livingston, UK, 18 April 2012; Two new technical notes examining experimental performance in fluorescence spectrometry have been published by the Photonics Division of Edinburgh Instruments. Entitled “Comparison of Stray Light Performance for FLS920 Spectrometers with either Single or Double Monochromators” and “Choosing the Correct Xenon Bulb: Ozone Free or Ozone Generating?”, these notes are available for download from the Edinburgh Instruments website, www.edinburghphotonics.com/spectrometers/Technical-notes.
“Comparison of Stray Light Performance for FLS920 Spectrometers with either Single or Double Monochromators” reports on the ‘real-life stray light performance’ of the fluorescence spectrometer equipped with standard single monochromators featuring 1800 g/mm gratings or double monochromators featuring 1200g/mm gratings. This difficult task, which requires comparison of very small signals with respect to a very large signal, was achieved by making measurements on light scattered from a PTFE sample, using a broad band xenon arc light source for excitation.
“Choosing the Correct Xenon Bulb: Ozone Free or Ozone Generating?” gives an overview of the wavelength dependence of excitation light from ozone free and ozone generating xenon bulbs. This is of particular interest since ozone generating light bulbs have synthetic quartz envelopes that transmit light with low wavelengths and therefore ozone is generated in the surrounding air. Ozone free xenon bulbs, however, are made from other UV-transmitting glasses that are specially made to cut off (absorb) light below 200nm to avoid ozone generation. The technical note also examines the effect of different gratings in the excitation and shows that, provided a suitable set of gratings has been selected, the range of excitation extends down to 200nm with an ozone generating bulb fitted to the Xe900 xenon lamp.