Photodiode Array Spectrometer Research Articles

Characteristics of Photodiode Arrays for Spectrochemical Measurements

A rather large number of spectrochemical studies and analyses can be greatly facilitated by the simultaneous measurement of spectral information over a range of wavelengths. Of particular importance and interest to analytical spectroscopists is the development of simultaneous multielement analysis systems. The development and implementation of such analyses have been hampered by a lack of convenient and versatile multichannel spectrochemical measurement systems. New detector subsystems based on modern electronic image sensors are helping to overcome this obstacle. One type of electronic image sensor is the self-scanning linear array of silicon photodiodes. These arrays are available with densities of 1024 photodiodes per in and in lengths of up to 1 in. They are packaged in conventional dual-in-line integrated circuit packages complete with the necessary scanning circuitry. These sensors have simple and inexpensive control and measurement circuitry, and superior blooming and lag performance when compared to most other electronic image sensors. In addition, the signal integrating capability of the arrays is a flexible and powerful asset for many spectrochemical measurements. These and other operational characteristics of photodiode arrays are emphasized in this study. In addition, the measurement capability of a computer coupled photodiode array spectrometer based on a 1024 element array which is capable of simultaneously measuring over 50 nm (500 Å) of continuous spectral information anywhere from 200 to 1000 nm is illustrated.

Simultaneous Multielement and Multiline Atomic Absorption Analysis Using a Computer-Coupled Photodiode Array Spectrometer

Development of simultaneous multielement atomic absorption analysis has been hampered by a lack of effective multichannel spectrochemical measurement systems. In this study a computer-coupled photodiode array spectrometer is applied to atomic absorption measurements. Using a multielement hollow cathode lamp source and this spectrometer system, a complete “atomic absorption spectrum” can be measured over a range of 130 Å. Both quantitative and qualitative absorption information can be simultaneously acquired for lines of several elements and several lines of one element. Results are presented for multiline atomic absorption of Cr and multielement atomic absorption of Ni and Cr, and Cr and Fe.

Automated Direct Current Arc Time Studies Using a Computer-Coupled Photodiode Array Spectrometer

A hardware and software system has been developed which is capable of automatically acquiring and analyzing intensity-time data from a dc arc source. This system is based on a computer-coupled photodiode array spectrometer with which 260 Å of continuous spectral information can be simultaneously measured and stored directly in a small computer. With the present system up to seven time sequential spectra, each representing the integral of the spectral intensity over times ranging from 1 to 10 sec, can be automatically obtained during a dc arc burn. The time interval spectra can then be analyzed under computer control and the intensity-time curves for any desired lines can be plotted on a computer terminal within about 2 min after termination of the are burn. The application of the system to some simple dc arc time studies is discussed and illustrated.

Simultaneous Multielement Quantitative Spectrochemical Analysis Using a DC Arc Source and a Computer Coupled Photodiode Array Spectrometer

Abstract Self scanning linear arrays of silicon photodiodes have been utilized as multichannel detectors in a variety of spectrochemical measurements (1,2,3,4). These arrays have densities of 1000 photodiodes per inch and can be thought of as completely solid state single line image sensors. In some earlier work (3) a spectrometer based on this detector was utilized for qualitative dc arc spectrochemical analysis. In this note we report on the utilization of an improved computer coupled photodiode array spectrometer system for simultaneous multielement quantitative analysis with a dc arc source.