Time-of-flight measurement

M.G.Silk, The use of diffraction based time-of-flight measurements to locate and size defects , Br.J.Non-Destr. Test., 1984, 26(4), 208-213. 

Fig.5. Energy cepstrum of HF signal and Time of flight measure.

Time-of-Flight Measurements with Shear Horizontal Waves. 

Prompted by the success, TOFD measurements were conducted on a fatigue crack in a stainless steel compact tension specimen. Test and system parameters were optimised following the same procedure used for carbon steel specimens. A clear diffracted signal was observed with relatively good SNR and its depth as measured from the time-of-flight measurements matched exactly with the actual depth. 

Although energy resolution is rarely employed in positron camera systems, scatter is not normally a problem. This is because of the very short time window within which two photons must arrive in order to be counted. At low decay rates, the incidence of accidental events is very low, rising only slightly for those that occur as the result of scatter. Some systems employ time-of-flight measurements of the time difference between the arrival of the two photons to obtain additional information about the location of an annihilation along the line. This has been used to improve resolution and statistical accuracy. Resolution is in the range of 3—4 mm and is less dependent on position than is SPECT (16). 

D. T. Delpy, M. Cope, P. van der Zee, S. Arridge, S. Wray, and J. Wyatt. Estimation of optical path length through tissue from direct time of flight measurements. Physics in Medicine and Biology, 33 1433-1442, 2004. 

Coulter counter analysis Sieve analysis Sedimentation analysis Time of flight measurements (Scanning electron) microscopy... 

Methods for analysis of the particle size distribution in the aerosol cloud include techniques such as time of flight measurement (TOE), inertial impaction and laser diffraction. Dynamic light scattering (photon correlation spectroscopy) is confined to particles (in suspension) in the submicron range. In addition to the size distribution, the particle velocity distribution can be measured with the Phase Doppler technique. 

Experimentally, the charge mobilities are obtained by time-of-flight-measure-ments or by characterizing held-effect-transistor devices made of the materials. In hme-of hight experiments, the mobility p is directly given by... 

A contact potential correction requires that in a retarding potential measurement the work function is replaced with that of the collector, and that in a time-of-flight measurement it is replaced with the average work function of the flight tube.30 In low temperature field evaporation, Qn is only about 0.1 to 0.2 eV, or less than the uncertainty of most experimental measurements, and can be omitted for practical purposes. 

Clearly, the data indicate that there is a large difference in the values of v. For the ANI/NI system, the time-of-flight measurements show that the anion (NI-) is more mobile than the cation (ANI+). The results shown in Fig. 7... 

Results for CO/Cu(001) were obtained with a model of electronic and vibrational transitions we have previously derived, with populations and quantum coherences calculated to compare with experimental results from femtosecond spectroscopy and time-of flight measurements. The present results show that the populations of individual vibronic states oscillate as a result... 

All these features are reminiscent of results obtained from time-of-flight measurements on highly pure molecular crystals (Section 1.4). This might indicate of that the intrinsic properties of these materials are being approached. 

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