Intensity, incident

Delta function response - Over most of the wavelengths of interest, optical and infrared detectors produce one photoelectron for every detected photon, which provides a one-to-one correspondence between detected photons and photoelectrons. This means that the detector response is exactly linear to the intensity incident on the detector - an attribute that allows astronomers to precisely remove sky background and electronic bias to accurately measure the intensity of the astronomical object. 

For concentrated or bulk samples a transmission experiment is both the simplest and the most effective. In essence, one measures the X-ray intensities incident and transmitted through a thin and uniform film of the material. Careful analysis of signal-to-noise ratio considerations indicates that optimal results are obtained when the sample thickness is of the order of 2.5 absorption lengths. Since in this case a simple Beer s law applies, the data are usually plotted as In(7//0) versus E. The intensities are measured using ionization chambers in conjunction with high-gain electrometers (see Fig. 11). 

Each photoelectrode was retested after mounting and current voltage plots obtained. All photoelectrodes decreased in performance and one became essentially inoperative. This is attributed to excessive handling during mounting which resulted in abrasion and deterioration of the deposit. The maximum power output of the individual mounted electrodes in the assembly varied from 5.TO mW to 0.13 mW. The maximum power obtained from the assembled converter was 27 mW. Under short circuit conditions the maximum power at 90.2 mA and 100 mV was 9 0 mW. The light intensity incident at the photocell was 92.5 mW/cm. ... 

One can thus estimate the total light intensity incident on a given volume of air in the troposphere due to direct solar radiation, scattering, and reflection. The light absorbed in that volume can then be calculated... 

I0 is the intensity incident upon the sample and I is the intensity of light transmitted by the column of gas at 1 atm. pressure and 0°C. (STP) and Ax cm. long. The constant a is, therefore, proportional to the absorptivity. Experimentally, a is not precisely constant but should be defined in terms of concentration, temperature, medium, etc. 

Feasibility studies have shown that a He-jet activity transport line, with a target chamber placed in the LAMPF main beam line, will provide access to short-lived isotopes of a number of elements that cannot be extracted efficiently for study at any other type of on-line facility. The He-jet technique requires targets thin enough to allow a large fraction of the reaction products to recoil out of the target foils hence, a very intense incident beam current, such as that uniquely available at LAMPF, is needed to produce yields of individual radioisotopes sufficient for detailed nuclear studies. We present the results of feasibility experiments on He-jet transport efficiency and timing. We also present estimates on availability of nuclei far from stability from both fission and spallation processes. Areas of interest for study of nuclear properties far from stability will be outlined. 

Fresnel s equations can be used to calculate the dependence of the reflectivity [(reflected beam intensity)/(incident beam intensity)] on the incident angle expressed in terms of the scattering vector Q (Fig. 5),... 

The source of this generation of higher optical harmonics has to be sou t in the circumstance that an intense incid it beam, of osdllation frequency cu, induces dectric polarizations of higher orders in the medium thus, in the case of frequency-doubling 2cu ... 

Petri factor. The UV intensity or irradiance may be different over the surface area of the targets (pathogens) to be irradiated. The Petri factor (Pp is then defined as the ratio of the average of the UV intensity (or incident irradiance) over the area of the Petri dish to the UV intensity (or irradiance) at the center of the dish. It is used to correct the intensity (irradiance) reading at the center of the Petri dish to more accurately reflect the average UV intensity (incident fluence) over the surface area. A well-designed collimated beam apparatus should be able to deliver a Petri factor ranging from 0.9 to 0.95. 

A collimated beam test is carried out to determine the UV microorganism s dose-response. The UV intensity (incident irradiance) of 1.00 mW/cm is measured using a radiometer. A 25-mL microbial suspension is irradiated for 60 s in a Petri dish. The irradiation time is monitored using a stopwatch. The Petri dish radius, measured using a ruler with 1 mm graduations, is 2.5 cm. The stir bar volume is 1 mL. The UV decadic absorption coefficient ( jq) of the microbial suspension for a 1-cm path length at 254 ran is 0.050 cm T The Petri... 

The value of nt used in Eq. (9-10) must be obtained by direct measurement, since it is not sufficiently accurate to use a tabulated value of n together with the measured thickness t of the specimen. To determine fit we use a strong diffracted beam from any convenient material and measure its intensity when the sheet specimen is inserted in the diffracted beam and again when it is not. The value of Ht is then obtained from the absorption law, I, = /oC" ", where /q and I, are the intensities incident on and transmitted by the sheet specimen, respectively. 

The absorptivity is a property that determines the fraction of the irradiation that is absorbed by a surface. The directional spectral absorbtivity of a surface is defined as the fraction of the spectral intensity incident in the direction of 9 and that is absorbed by the surface ... 

For heat transfer predictions, the radiative heat flux through a surface (with normal ) is required, which is determined by integrating the radiation intensity incident from all directions (i.e., 4ji steradians) as... 

Boundary Conditions for the RTE. The solution of the radiative transfer equation in a given geometry is subject to boundary conditions, which give the radiation intensity distribution on the boundaries. The boundary intensity is comprised of two components (1) contribution due to emission at the boundary surfaces and (2) contribution due to diffuse and specular reflection of radiation intensity incident on the boundaries. The radiation incident on the boundary is due to intensity emitted from all volume and surface elements in the medium. In mathematical terms, the general boundary condition on any surface element is written as [1,6] ... 

The inclusion of the extra optical elements (e.g., the four extra bounces from the two detuned channel-cut postmonochromator crystals) in the optical path while producing the desired effect of increasing the XSW phase (or atomic positional) resolution, come at the cost of reducing the X-ray intensity incident on the sample. Using Figure 12a one can visually estimate this effect by comparing the emittance from the second Si(004)... 

Density of distribution of division times Light intensity incident light intensity Kernel in Volterra s equation [Eq. (34)]... 

The absorption of x-rays is governed by the expression, I/Iq = where Iq is the intensity incident on a slab of thickness x, / is the transmitted intensity, and p is the absorption coefficient. The mass absorption coefficient is defined by p/p where p is the density. Compare the trans-mittances of 1.0 cm slabs of each of the following elements. The mass absorption coefficient is for radiation with 2 = 20 pm. 

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