Xenon-radiation

Radiation from a Xenon-radiation or a Deuterium-source is focussed on the flow cell through a filter. The fluorescent radiation emitted by the sample is usually measured at 90° to the incident beam. The second filter picks up a suitable wavelength and avoids all scattered light to reach ultimately the photomultiplier detector. 

Holroyd RA, Nishikawa M, Itoh K. (2005) Rates and energy of reactions of charged species in supercritical xenon. Radiat Phys Chem 74 146-151. 

Refer to Figs. 14.3 and 14.4 for photographs of a photo-stability chamber using a xenon radiation source (Option I) and a photo-stability chamber using two separate radiation sources (Option II). 

The activation spectrum for yellowing and decrease in brightness of newsprint paper exposed to xenon radiation has been obtained using the cut-on filter technique [44]. As seen in Fig. 4, the wavelength interval 335 to 380 nm was mostly responsible for both yellowing and brightness reversion of paper. 

Photooxidation of PVC yielding carbonyl functionafities in the polymer is linear in time up to several hundreds of hours of exposure to xenon radiation. Using the cut-on filter technique and assuming the rate of carbonyl formation to... 

Recently, Zhengfeng reported [134] an activation spectrum for changes in optical density due to carbonyl functionalities, and in tensile strength, for polypropylene exposed to both filtered xenon radiation and to sunlight (Guangzhou, China). They found qualitative similarities between the two exposures and maximum degradation in the interval A = 300-350 nm in several exposures spanning durations of up to 136 h. 

Fig. 14. A cumulative spectral sensitivity curve for the decrease in average elongation at break of injection molded unstabilized LDPE samples exposed to flltered-xenon radiation, behind a series of different cut-on filters. Two sets of data for different commercial LDPE resins are shown. The error bars show the standard error of the mean [133]...

Tests to simulate the process of ageing with xenon radiation according to DIN EN ISO 4892-3 2006 confirm the forecast that ETFE-foils have good durability over 25 years. 

There are many types of electronic detector. The original fomi of electronic detector was the Geiger counter, but it was replaced many years ago by the proportional counter, which allows selection of radiation of a particular type or energy. Proportional counters for x-rays are filled witii a gas such as xenon, and those for... 

The aluminium absorbs the radiation, heats up and transfers the heat to xenon gas contained in the cell. As the temperature of the gas varies the curvature of a flexible mirror of antimony-coated collodion, forming a part of the cell, changes. Reflection of a light beam from this mirror, which is on the outside of the Golay cell, indicates its curvature and therefore the intensity of radiation absorbed by the cell. 

From about 1970, but before the availability of suitable lasers, Parmenter and others obtained SVLF spectra, particularly of benzene, using radiation from an intense high-pressure xenon arc source (see Section 3.4.4) and passing it through a monochromator to select a narrow band ca 20 cm wide) of radiation to excite the sample within a particular absorption band. 

Fig. 5. Effect of uv exposure on nylon-6,6 yam tenacity and whiteness with and without copper salt and alkah haUde in polymer scoured 210-denier 34-filament yams exposed in Xenon-arc Ci65 Weather-Ometer using radiation intensity of 0.55 W/m at a wavelength of 340 nm. Exposure from 0 to 800...

A continuous source has to be employed to record absorption spectra. Fluorescence is usually excited with mercury vapor lamps in the region of their major bands they radiate more powerfully than do xenon lamps (Fig. 14). 

Fig. 14 Radiation characteristics of a high pressure Hg lamp (Osram HBO 100 continuous line) and of a xenon lamp (PEK 75 broken line) [4]. The intensity /is represented logarithmically in relative units.

High pressure xenon lamps are also employed in some TLC scanners (e.g. the scanner of Schoeffel and that of Farrand). They produce higher intensity radiation than do hydrogen or tungsten lamps. The maximum intensity of the radiation emitted lies between k = 500 and 700 nm. In addition to the continuum there are also weak emission lines below k = 495 nm (Fig. 14). The intensity of the radiation drops appreciably below k = 300 nm and the emission zone, which is stable for higher wavelengths, begins to move [43]. 

The chemistry of xenon is much more extensive than that of any other noble gas. Only one binary compound of krypton. KrF2, has been prepared. It is a colorless solid that decomposes at room temperature. The chemistry of radon is difficult to study because all its isotopes are radioactive. Indeed, the radiation given off is so intense that it decomposes any reagent added to radon in an attempt to bring about a reaction. 

Since the intense UV radiation emitted by these lamps is damaging to the eyes, it is essential never to look at the unshielded lamp when it is on. Care must also be exercised in the handling and use of the commonly employed high-pressure xenon lamps, which may shatter and explode if dropped. 

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