Aj Arij Rijke

Numerical investigation on the replacement of mercury by indium iodide in high-intensity discharge lamps

Mercury-free high-pressure discharge lamps have been studied by means of a radial-dependent model. Xenon and indium iodide are chosen as start gas and buffer, respectively. Local thermodynamic equilibrium is assumed with a single temperature for all species. The model consists of the coupled description of the balance equation for the plasma temperature with the radiation transport equation. The plasma composition is calculated according to the Guldberg–Waage, Boltzmann and Saha laws. These laws were supplemented by additional equations specifying the total pressure, constant element ratios and quasineutrality. The model takes into account atomic, molecular as well as continuum radiation. The broadening of the optically thick lines is approximated by Stormbergs approach. The predicted spectrum is compared with a measured one and shows good agreement on a qualitative scale. From this comparison it is concluded that the largest part of the continuum radiation is produced by the free–free and free–bound AX transition in InI.

On the atomic line profiles in high pressure plasmas

In a previous contribution to this journal [H. P. Stormberg, J. Appl. Phys. 51(4), 1963 (1980)], Stormberg presented an analytical expression for the convolution of Lorentz and Levy line profiles, which models atomic radiative transitions in high pressure plasmas. Unfortunately, the derivations are flawed with errors and the final expression, while correct, is accompanied by misguiding comments about the meaning of the symbols used therein, in particular the “complex error function.” In this paper, we discuss the broadening mechanisms that give rise to Stormbergs model and present a correct derivation of his final result. We will also provide an alternative expression, based on the Faddeeva function, which has decisive computational advantages and emphasizes the real-valuedness of the result. The MATLAB/Octave scripts of our implementation have been made available on the publishers website for future reference.

A calibrated integrating sphere setup to determine the infrared spectral radiant flux of high-intensity discharge lamps

A setup that aims to determine the infrared radiation fraction of the energy balance of high intensity discharge (HID) lamps has been designed, constructed and calibrated. It consists of a high-resolution integrating sphere that can cover a wide spectral range. New in this work is that the integrating sphere measurements can be used in the infrared part of the spectrum up to 10 µm and that we have calibrated the absolute intensity in that range. No calibration standards for spectral radiant flux are readily available in the infrared. Therefore, we have used a resistive heated platinum ribbon as absolute intensity reference. As a first test case, this new setup was used to determine the energy balance of a Philips CDM-T 70W/830 lamp, which is a type of metal halide HID lamp.

Determination of the spectroscopic properties of indium bromide

To develop a more efficient plasma light source, molecules are considered as the prime source of radiation because they can potentially avoid the conversion losses of the low-pressure mercury lamp as well as the thermal losses of the high-pressure mercury lamps. A candidate to serve as the prime radiator in such a lamp could be indium bromide, but spectroscopic data to assess its aptitude are largely unavailable. To increase the knowledge of the spectroscopic properties of these molecules and InBr in particular, an experiment was designed to acquire this information. Laser-induced fluorescence was used to study the radiative properties of InBr for lighting purposes. Using an innovative method to interpret the measured data, detection--excitation (detex) plots, more information can be obtained from the spectra. Also the effect of a background gas and plasma was investigated for both a capacitive and an inductive plasma. Mainly the electronic A-state of InBr was investigated. Results include newly identified rotational transitions, vibrational constants, rotational constants for different vibrational levels, band head wave numbers and Franck–Condon factors for various vibrational transitions.