Irradiation device

The SPE is defined as the ratio of the time required to produce a perceptible erythema on a site protected by a specified dose of the uv protectant product to the time required for minimal erythema development in the unprotected skin. An SPE of 8 indicates that the product allows a subject to expose the protected skin 8 times as long as the unprotected skin to produce the minimum erythema response. The measurement can be quite subjective unless skin color and the history of reactions to sun exposure of the test subjects are taken into account. The MED range for Caucasians at 300 nm averages 34 mj/cm. The range is 14—80 mj/cm. Perspiration or the use of artificial irradiation devices can create additional problems. 

Matusiewicz, H. and E. Stanisz. 2007. Characteristics of a novel UV-Ti02-microwave integrated irradiation device in decomposition processes. Microchem. J. 86 9-16. 

Fig. 4.9. Fibre optics conducting the photons of a high-pressure mercury arc into the cell compartment. The cell holder is temperature controlled and stirred (M). The circular area of the fibre optic (L) is transformed to a rectangular cross section (T) fitting to the dimensions of the cell. In front of the light source a shutter PS and a lens are positioned. The interference filter F selects the wavelength. The irradiation device is fixed on top of the spectrometer by an...

This modular apparatus allows even very special applications. As a further example a combined measurement and irradiation device can be set up where the sample is placed in a Dewar and kept at low temperature. Fast shutters, a beam splitter, and a repositioning device for sample and reference allow the uninterrupted examination of photochemical reactions under specific conditions (see Fig. 4.12) [54]. 

Figure 8.2 presents the measured capacitance as a function of gate voltage at 1 MHz before and after LF+ ion irradiation at the flowing fluences of 5 x 10 , 1 x 10", 5 x 10", 1 x lO Li cm, respectively, at room temperature. The shift in the flat band voltage (Vj ) of the irradiated devices is extracted from C-V curves by comparing with the ideal curve. It is found that the V, reduces with increasing fluence from -1.65 V for unirradiated devices to -0.96 V for 1 x 10 LF+ cm- irradiation. 

Figure 8.4 shows the changes in series resistance (RJ of the HfOj-based MOS-CAP devices before and after irradiation for various Li°+ ion fluences. It is observed that the values of the series resistance (Rj) increase as the ion fluence increases from 5 x 10 ° to 1 x 10 ° LP+ cm"° with respect to a virgin sample. The increase in series resistance of irradiated devices is attributed to the nonuniformity in the dopant distribution in the silicon bulk caused due to Li ion irradiation. Similar effects of change in dopant distribution have also been reported for other radiation sources (Wei and Ma 1984, de Vasconcelos and da Silva 1996). 

Figure 5 shows a schematic arrangement of a Co ° irradiation device cooled by spotcooling. In order to cool down all the samples in the ampoule it is necessary to spray liquid nitrogen over the entire ampoule. Heaters are employed to provide temperature control by attaching the temperature sensor to the ampoule wall and controlling the heater current. 

Low-temperature irradiation devices are used with increasing frequency, especially to study radiation-induced defects in solids. A liquid-nitrogen irradiation device, which has operated for over 15,000 hours, has been described previously P]. However, certain defects anneal out or are transformed well below 77 °K and their study requires irradiation at lower temperatures. Two liquid-helium [ " ] and one liquid-hydrogen [ ] reactor irradiation devices have been reported in the literature. This paper describes an irradiation device at the temperature of boiling neon, which was installed in the Melusine swimming-pool reactor of the Nuclear Research Center of Grenoble. 

In January 1959, BR-5 reactor having 5 MW rated power was put into operation at the IPPE. There are three heat removal circuits in the BR-10 facility (sodium in the primary circuit, originally sodium-potassium and then sodium — in the secondary circuit, and air in the third circuit) with two parallel loops. Initial parameters of the primary and secondary coolants were respectively 430/500°C and 380/450°C, i.e. close to those of power FR. Now sodium temperatures in the primary and secondary circuits are respectively equal to 330/450°C and 270/370°C. There is a wide range of experimental devices in the reactor, namely test channels and irradiation devices and beams of thermal and fast neutrons. There are 5 dry instrumented channels in the reactor. Fast neutron flux in the central loop channel is up to 8.4x lO " n/cm -s. 

The simplicity of sample preparation is one of the main advantages of the technique. Solids, liquids, and even gases are analyzed directly as received with no prior treatment. The sample is sealed in a suitable container, usually of polyethylene or quartz glass, and placed in the irradiation position in the reactor. When quantitative analysis is carried out with chemical standards, it is necessary to ensure that the samples have a constant geometry for irradiation and y-ray spectrometry. Samples are therefore used in powder form or as chunks of uniform shape and thickness. In the case of liquids, identical volumes must be used to provide consistent geometry and great care is required to ensure that no leaks occur in the irradiation site. Reactor operators have strict control over samples allowed in the irradiation devices and hazardous materials will not be permitted. 

New designs of irradiation devices for the production of radioactive isotopes, in particular cobalt-60, were tested in the steel blanket. The key innovation in these designs was the absence of the absorber elements. In the course of the experiments, power bursts up to 50% were revealed on the core boundary. Since the considerable decrease of power is observed in the core periphery, these bursts are unlikely to cause the parameters of power reactor standard fuel subassemblies to go over permissible operating limits. However, the final conclusion on this issue can be drawn only after the comprehensive analysis of S/A performance taking into account the obtained experimental data. 

Markgraf J F W, Tartaglia G P and Tsotridis G (1995), Irradiation devices and irradiation programmes at the high flux reactor (HFR) Petten for the investigation of the irradiation behaviour of stainless steels , Nucl Eng Design, 159,81-89. 

PRINCIPLE OF A LIQUID NITROGEN IRRADIATION DEVICE AND ITS REALIZATION FOR USE IN A SWIMMING-POOL TYPE REACTOR... 

Because of the decay times needed, the trader s investment risk in the virgin material is a long time compared to the gem trade s cultural time frame. The reactor facility has an investment risk in the irradiation devices and the development of the measuring equipment. The facility is also dependent on the delivery of good quality virgin material so that it is not left with a large quantity of material that is useless because of long lived activation products. 

These PISs can initiate the photopolymerization of synthetic, as well as renewable, monomers/oligomers. A careful adaptation of the PISs to novel light sources avoiding the harmful mercury lamps emitting UVA and UVB or even UVC rays has been possible, and today, polychromatic visible light irradiation devices (Xe, Hg-Xe and doped lamps), quasi-monochromatic devices (LED arrangements) or monochromatic devices (laser diode arrays) can be safely used. 

The reactor core (i.e. the fuel elements, reflectors, cooling channel geometry, irradiation devices and structural parts) shall be designed to maintain the relevant parameters within specified limits in all operational states. There shall be provisions in the design to monitor the integrity of the fuel. In the event of the detection of fuel failure, an investigation shall be conducted to identify the failed fuel element. Authorized limits shall not be exceeded (see also paras 7.96-7.102) and if necessary the reactor shall be shut down and the failed fuel element shall be unloaded from the core. 

Medium and high activity waste is stored at the Cadarache Center. High activity waste consists mainly of parts from the nickel and steel reflector assemblies or from control-rod mechanisms and irradiation devices. These account for the major part of the total radioactivity (4800 TBq) which has been removed from the reactor. The liquid effluent produced by washing and decontaminating operations was transferred to the Liquid Waste Treatment Facility at Cadarache where it has been neutralized, concentrated by evaporation and encapsulated in bitumen or cement. Furthermore, on completion of the partial dismantling work, about 300 tons of material (steel and lead in particular) will been returned to service. Much of this will be turned into biological radiation shielding. 

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