Beam detectors

Figure 2 Cross section versus incident proton energy for the (p, cx) N reaction, with a beam-detector angie of 165°. ...

Gas detection is provided in the petroleum industry to warn of and possibly prevent the formation of a combustible gas or vapor mixture that could cause an explosive overpressure blast of damaging proportions. There are two types of gas detectors used in the oil and gas industry. The most common and widely used is the catalytic detector. More recently, infared (IR) beam detectors have been employed for special "line of sight" applications, such as perimeter, boundary or offsite monitoring, pump alleys, etc. 

Where overall large area coverage is necessary or desired, such as the monitoring of facility borders, pump alleys, entire onshore units or offshore modules, "line of sight" IR beam detectors are used, otherwise "point source", catalytic detectors are provided. The point source locations should be at least on either side of the leak point, which at least one of the detectors downstream ventilation pattern. 

Boundary and Offsite - Especially critical for locations near to public exposures, an IR beam detector can be used to signal if vapors or gases may be released to offsite locations. 

The use of laser-induced fluorescence as a molecular beam detector for the measurement of internal state distributions of reaction products is presented and applied to the reactions of barium with the hydrogen halides. It is found that most of the reaction exoergicity appears as translational energy of the products and that the total reactive cross section is positively correlated with the average fraction of the exoergicity appearing as vibrational excitation. 

In this paper we describe the use of laser-induced fluorescence as a molecular beam detector and apply it to the reactions of barium atoms with hydrogen halides,... 

LASER-INDUCED FLUORESCENCE AS A MOLECULAR BEAM DETECTOR... 

For more than a century, phosphors that emit visible light when exposed to ionizing radiation have been used for a variety of scientific and engineering purposes. These materials exhibit a large fluorescence efficiency that makes them an effective accelerator beam detector or positioning system. Any phosphor used for this purpose will be exposed to large doses of beam radiation. This candidate material must be able to withstand such doses with a minimal reduction of fluorescence. 

Specialist batteries, which are generally shorter than general purpose batteries are selected by a simple size measurement. This is undertaken by the use of two through-beam detectors fitted approximately 50 millimetres apart. Only standard consumer size batteries are allowed to pass this point. 

Fig. 15.8 FIA configurations for the off-line speciation of chromium, (a) With a splitting point (A) and a dual-beam detector (a.1) with two cells aligned with the light path (a.2) with a merging point prior to a single flow-cell (a.3). (b) Sequential determination with the aid of a selecting valve. DPC diphenylcarbazide Ox oxidant [Ce(IV)] q flow-rate Vi injection valve L and 0 reactor length and inner diameter V2 selecting valve W waste. (Reproduced from [37] with permission of Elsevier).

Figure 21 27 shows a contmon design <.i an AFM. The movement system is a tubular pie/oeleciric device that moves ihc sample in v. y. and z directions under the tip. I he signal from ihe laser beam detector is then fed... 

Fig. 10. Schematic layout of laser-induced photoacoustic spectroscopy with dual beam detector system (R S reference and sample cells) [22]...

Figure 2.18 Principle of the Brewster angle spectroscopy technique LS, light source M, monochromator C, chopper, D f, reference beam detector LI, A, lock-in amplifier and current amplifier Pol, Clan-Thomson...

Lateral foree microscopy (LEM) is a variant of the dc-contact mode, specifieally the constant-force mode, in which the laser-beam detector is arranged so as to allow monitoring not only of the vertical component of the tip deflection (topography), but also the... 

For comparison with the experimental 1(0), the c.m. cross section laboratory frame by using the elastic Jacobian and then averaged over the velocity distributions of the two beams and over the beam/detector geometry. 

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