Counting technique

In addition to the 4 stable isotopes sulfur has at least 9 radioactive isotopes, the one with the longest half-life being which decays by activity (Kmax 0.167 MeV, 87.5 d). can be prepared by Cl(n,p), S(n,> ) or S(d,p) and is commercially available as SeicmcQt H2S, SOCb and KSCN. The radiation has a similar energy to that of C ( mav 0.155 MeV) and similar counting techniques can be used (p. 276). The maximum range is 300 min in air and 0.28 mm in water, and effective shielding is provided by a perspex screen 3-10 mm thick. The preparation of many - S-containii compounds has been... 

In the carbon-14 expts, HMX/RDX product was isolated qualitatively, separated Into its components, and each component assayed for carbon-14 beta radioactivity using a liquid scintillation counting technique (Ref 11). DPT-l4C was isolated as an intermediate product from the reaction mixt and similarly radioassayed. For the nitrogen-15 tagged AN expts, HMX and RDX were assayed mass spectrometrically for i5N/i4N ratios from which atom %1SN contents were calcd. In die course of these expts, each tagged species was added initially and also at subsequent stages of the reaction process. The important observations and results are summarized as ... 

A scintillation ion detector, described in detail elsewhere (41), detected virtually every ion which entered the detector chamber. Pulse counting techniques were used. 

IDF (1991). Enumeration of microorganisms colony count technique at 30 °C, Standard lOOB. 

As discussed above, mass spectrometric techniques are the methods of choice for measurement of nuclides pertinent to this study. They supercede earlier decay-counting techniques because of their ability to detect a much larger fraction of the nuclides of... 

Measuring the isotopic composition of U in estuaries has the potential for further constraining the interpretations of uranium behavior. However, this has been hampered by large uncertainties in conventional methods using counting techniques. While rivers often display ( " U/ U) activity ratios above equilibrium, the ratios generally do not... 

Am that has been deposited into specific organs or tissues, such as the lungs, liver, bones, or lymph nodes, can be detected and quantified using whole body counting techniques that appropriately... 

In assessing initial exposure, whole body counting techniques measure amounts of americium that have been deposited within organs or tissues and have not been excreted. In cases of accidental ingestion, some of the americium may have been excreted in the urine or through the feces, before exposure is assessed. In... 

Special attention must be paid to the interpretation of particle size data presented in terms of either weight or number of particles. Particle weight data may be more useful in sedimentation studies, whereas number data are of particular value in surface-related phenomena such as dissolution. Values on the basis of number can be collected by a counting technique such as microscopy, while values based on weight are usually obtained by sedimentation or sieving methods. Conversion of the estimates from a number distribution to a weight distribution, or vice versa, is also possible using adequate mathematical approaches, e.g., the Hatch-Choate equations. 

The velocity mapping-ion counting technique increases the resolution of imaging data. This is clearly seen when it is compared with the data from the conventional Wiley-McLaren imaging apparatus2 or even the... 

The conventional radiocarbon decay counting technique generally provides reliable results, but it has some limitations the following are worth mentioning ... 

Transfer of technetium from seawater to animals has been studied by laboratory experiments using 95mTc, The advantages of 95mTc over "Tc are 95mTc emits y-rays, thus whole-body counting techniques can be used, and it has a sufficiently high specific activity because of its relatively short half life (61 d). 

Advanced Time-Correlated Single Photon Counting Techniques... 

In this paper, the photofragmentation of transition metal cluster complexes is discussed. The experimental information presented concerning the gas phase photodissociation of transition metal cluster complexes comes from laser photolysis followed by detection of fragments by ionization (5.). Ion counting techniques are used for detection because they are extremely sensitive and therefore suitable for the study of molecules with very low vapor pressures (6.26.27). In addition, ionization techniques allow the use of mass spectrometry for unambiguous identification of signal carriers. 

Becker, W. (2005). Advanced time-correlated single photon counting techniques. Springer, Berlin Heidelberg New York. 

The instruments include an ionization chamber, the charcoal-trap technique, a flow-type ionization chamber (pulse-counting technique), a two-filter method, an electrostatic collection method and a passive integrating radon monitor. All instruments except for the passive radon monitor have been calibrated independently. Measurements were performed... 

Nazaroff, W.W., Optimizing the total-alpha three-count technique for measuring concentrations of radon progeny in residences, Health Phvs. 46 395-405 (1984)... 

As can be seen in Fig. 3b, it is important to specify whether data are represented as a number distribution (obtained by a counting technique such as microscopy) or as a weight distribution (obtained by methods such as sieving), since the results will not be the same. Hatch and Choate [4] have developed equations for converting one type of diameter to another the relationships between them are summarized in Table 2. Note that caution should be exercised in using the Hatch-Choate conversions if the distributions do not closely fit the log-normal model. While this distribution is the most frequently used to describe pharmaceutical systems, other distribution functions have also been developed [2,5,6],... 

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