Radiation absorption length

Radiation groups (2) (Ratio of L to radiation absorption length and blackbody radiation flux to enthalpy convection),... 

To increase the radiation absorption and ionization efficiency of IR YAG-Nd laser (wave length - 1064 nm) used in for analysis of synthetic oxide single crystals Bi Ge O, Li MoO, LiB O, the samples were grounded and pills of 010 mm were pressed and analyzed by LIMS EMAL-2 (Uki aine) ... 

D0 the optical absorption length is the distance the infrared radiation can travel through the sample (cm), equal to 1/p where P is the optical absorption coefficient... 

Thickness of material, radius of hemisphere or mean beam length in radiating gas, m or ft Absorption length, m or ft... 

Equation (1) shows that an increase in material density will reduce the radiation signal and vice versa. The transmitted radiation intensity is measured and recorded via an interfaced portable computer at predetermined length intervals or positions along the side of the column. A radiation absorption profile (the "scan profile") is then produced. 

The nucleons consist mainly of photons, electrons, and positrons, and compose about 10 percent of the cosmic radiation at sea level. A fraction of muons and nucleons are absorbed while traversing the atmosphere. Variations in absorber thickness (air mass) are proportional to variations in barometric pressure. The absorption length for cosmic-ray muons at sea level in the atmosphere is 4,000 g/cm (Cocconl, 1951), and for cosmic nucleons, 120 g/cm (Hayakawa, 1969). Thus, it is clear that muons have significantly higher penetrating power than nucleons, about 33 times in the air. The probability of absorption rapidly increases with the atomic number, Z. In terms of lead shielding, these muons can penetrate a meter or more, while nucleons can be stopped in several inches of lead. 

The resolution of the time delay measurement, and therefore the velocity resolution, will depend on the spread in the correlation function which in turn will depend on (i) the range of particle speeds coupled with the distance between the detectors and (ii) the spatial (hence time) resolution of the detectors. In the case of capacitance sensors, the spatial resolution will be approximately the length of the electrodes in the direction of flow, whereas in a radiation absorption technique the width of the received beam will be the determining factor. The spatial resolution of pressure and acoustic signals is much longer as the acoustic transmission properties of the gas and (in the case of acoustic techniques) the pipe is relevant. 

The heat power density H, released in the material as the result of all nonradiative de-excitation processes, appears as the source term on the right hand side of the heat-diffusion equation. The spatial size and shape of the source volume depend on the light-beam geometry and on the absorption length in the material. Similarly, the time dependence of the heat source is determined by the time evolution of the light excitation and by the relaxation processes in the material. A photoacoustic effect can be generated by modulated radiation as well as by pulsed radiation. As the theoretical treatments of the two cases are different, they will be discussed separately. 

No detector can absorb completely all the radiation. In practice, a detector thickness of about two absorption lengths is used this captures about 90% of the energy that enters the material. 

Half-absorption length of water for keV radiation only a fraction of a mm. Special cell would be required for in situ measurements through front of the electrode. 

A key factor in the design of electrochemical cells for in situ transmission Mossbauer measurements is to decrease the attenuation of the y-ray beam, so as to reduce the time required for spectra acquisition. This may be accomplished by selecting low-absorption materials for windows and electrode supports and by minimizing the amount of electrolyte in the beam path. Radiation in the keV range penetrates rather deeply into matter, and therefore small amounts of rather high-Z elements can be tolerated without seriously comprising the overall cell transmission. As a means of illustration, the half-absorption length for 14.4-keV X-rays in water is about 3.5 mm, which is approximately... 

In the microwave region tunable monochromatic radiation is produced by klystrons, each one being tunable over a relatively small frequency range, or a backward wave oscillator, tunable over a much larger range. Both are electronic devices. Absorption experiments are usually carried out in the gas phase, and mica windows, which transmit in this region, are placed on either end of the absorption cell, which may be several metres in length. Stark... 

In the this form the Beer-Lambert law shows that the intensity of radiation transmitted by an absorbing sample declines exponentially as the length over which the absorption takes place increases. If the radiation, travelling with the speed of light c, takes time tg to traverse the absorbing path f Equation (9.29) becomes ... 

Both the a-X and b-X transitions have long been known from absorption by the oxygen in the earth s atmosphere, the source of radiation being the sun and the very long path length of oxygen overcoming their extreme weakness. For laboratory observation of these transitions, and particularly for accurate determination of absolute absorption intensity, CRDS has proved to be an ideal technique. 

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