Detector, wide dynamic range array

Wide Dynamic Range Array Detector for Absorbance and Rotation Spectrometry... 

HPLC provides reliable quantitative precision and accuracy, along with a linear dynamic range (LDR) sufficient to allow for the determination of the API and related substances in the same run using a variety of detectors, and can be performed on fully automated instrumentation. HPLC provides excellent reproducibility and is applicable to a wide array of compound types by judicious choice of HPLC column chemistry. Major modes of HPLC include reversed phase and normal phase for the analysis of small (<2000 Da) organic molecules, ion chromatography for the analysis of ions, size exclusion chromatography for the separation of polymers, and chiral HPLC for the determination of enantiomeric purity. Numerous chemically different columns are available within each broad classification, to further aid method development. 

The above discussion is presented merely to give an idea of the types of EUV detectors and their applications in use on present fusion plasma experiments. It is by no means an exhaustive list of possibilities. Indeed, several different detectors are in use or being planned in future experiments. Resistive anode encoders will probably see more use in fusion experiments as they become commercially available. However, the low count rates available ( 10 to 10 sec-1) will result in these detectors being used mostly for line profile studies (e.g., ion temperature measurements via Doppler broadening measurements). Intensified CCD arrays (back-illuminated or otherwise), vidicon or CID systems, lens-coupled intensifiers, and anode detectors have all seen some use on tokamak experiments or are planned for the near future, but have not been widely used as yet. However, in terms of availability, pixel format, dynamic range, insensitivity to magnetic fields, compact package, and moderate cost, the IPDA remains the most versatile multichannel EUV detector for plasma spectroscopy. 

The importance of a large dynamic range becomes obvious when taking into account measurements with strong background absorption as well as simultaneous measurements over a wide spectral region. From this point of view, CCD arrays are the most favored CS AAS detectors and were selected for the research spectrometers. Typical values for the saturation capacity between 600 000 and 800 000 electrons per pixel and a read-out noise of 5 to 30 electrons result in a shot-noise limited dynamic range of 600 to 800, which is quite sufficient for AAS applications. 

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