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Spectroscopic Methods
Published in Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus, Environmental Chemical Analysis, 2018
Somenath Mitra, Pradyot Patnaik, Barbara B. Kebbekus
Tungsten filament lamps are common broadband sources used in the visible region of the spectrum. They have an operating temperature of about 3000 K. At this temperature, the peak of radiation is actually in the near infrared, and the emission in the visible range is only a small fraction of the total energy emitted from the lamp. While running the lamp filament at a much higher temperature will give more radiant energy in the visible, it will also shorten the lamp's useful lifetime. The use of bromine or iodine vapor in the lamp fill gas, combined with a fused silica envelope allows a longer lifetime at elevated temperatures. So these quartz–halogen lamps are widely used. Xenon arc lamps require higher voltages but are often used as excitation sources for fluorescence measurements, because they produce a wide continuum, which extends into the ultraviolet region. In the ultraviolet, hydrogen or deuterium electrical discharge lamps are used. These lamps are filled with a low pressure of hydrogen or deuterium, and a DC voltage of about 40 V is applied. The envelope is made of quartz or fused silica. The low wavelength cutoff of these lamps depends on the transmission of the window material, and is usually about 180–200 nm.
Incoherent Light Sources
Published in Daniel Malacara-Hernández, Brian J. Thompson, Advanced Optical Instruments and Techniques, 2017
A version of a xenon arc lamp is used for photography. Xenon flash lamps have spectral distribution that closely resembles CIE D65 illuminant or daylight. Photographic flash lamps can stand more than 10,000 flashes. Flash tubes cannot be connected in parallel, since each lamp must have its own capacitor and trigger circuit. For multiple lamp operation, a slave flash lamp is designed to trigger with the light from another lamp. Flash lamps are synchronized to the camera in such a way that lamps are triggered when the shutter is fully opened. This is called the X-synchronization.
Light Sources
Published in Toru Yoshizawa, Handbook of Optical Metrology, 2015
Xenon arc lamps provide smooth continuum from near UV through the visible and into the near IR with pronounced xenon lines between 750 and 1000 nm. As xenon lamps produce bright white light that closely mimics natural daylight, they are appropriate for applications involving solar simulation, in projection systems, as well as absorbance and fluorescence research that require high-intensity broadband sources. The mercury–xenon arc lamps have essentially the mercury spectrum with xenon’s contribution to the continuum in the visible and some strong xenon lines in the near IR. Xenon and mercury–xenon arc lamps operate at very high pressure and temperature, and therefore, have to be handled with care to avoid contamination of the bulb and thermal stress. They emit strong UV radiation and require proper safety measures: protective goggles and gloves, and the lamp must be operated in a fully enclosed housing.
Development of a truncated ellipsoidal reflector-based metal halide lamp solar simulator for characterization of photovoltaic cells
Published in Energy Sources, Part A: Recovery, Utilization, and Environmental Effects, 2021
Muhammad Abdullah Haroon Shah, Hamza Butt, Muaaz Farooq, Muhammad Nouman Ihsan, Muhammad Sajid, Emad Uddin
The major components of the simulator are light assembly and reflector. Xenon arc lamps have been used preferably in commercial simulators and different PV studies to produce a spectrum closely matching to sunlight. However, the xenon lamp with its associated power and cooling system is much expensive as compared to a metal halide lamp (Codd et al. 2010b; Petrasch et al. 2007a). Furthermore, cost-effective simulators have employed metal halide lamps to achieve the required objectives at a lower cost (Ekman, Brooks, and Akbar Rhamdhani 2015; Parupudi, Singh, and Kolokotroni 2019; Siegel and Roba 2018). Therefore, a 1000 W Philips metal halide lamp is selected. Reflectors or light-concentrating devices need special attention while considering the cost. Ellipsoidal reflectors having large sizes are not readily available while the companies equipped with the required expertise provide these products at expensive prices (Parupudi, Singh, and Kolokotroni 2019; Siegel and Roba 2018; Wang et al. 2014). Using 3D printing and casting, manufacturing cost of the ellipsoidal reflector is kept close to 140. USD