Coincidence Methods

W. Bothc (Heidelberg) the coincidence method and discoveries made therewith. 

Orr [14] has proposed a scintillation and fi-y coincidence methods for the determination as measured by 220radon emanation. 

Applications. The —y coincidence method can be used to determine trace amounts of a -emitting isotope in the presence of large quantities of a y emitter with no coincident beta. The application of this technique is illustrated by the spectrum of a separated cesium sample... 

Many experiments (see Section I.B) require the energy analysis and detection of two or more particles with time correlation in other words, coincidence counting techniques must be used. Coincidence methods have long been used in nuclear physics because of the convenient fast detectors that have long been available. The more recent availability of fast, high-gain electron multipliers has created the possibility of coincidence measurements in electron spectroscopy. Various aspects of coincidence measurements have been discussed elsewhere.100 102... 

Wap66] Wapstra AH 1966 The coincidence method, in Alpha-, beta- and gamma-ray spectroscopy, Vol. I, ed. K. Siegbahn (North-Holland, Amsterdam) p. 539. 

S5) Schulze, W. Application of Coincidence Methods in Activation Analysis. Modem Trends in Activation Analysis-Proceedings of the 1965 International Conference in College Station, Texas, April, 1965. A and M College of Texas, College Station Texas, pp. 272—278 (1965). 

B) Fujii, I., A. Tani, H. Muto, K. Ogawa, and M. Sato A Rapid Method for Praseodymium by 14 MeV Neutron Activation. Application of Gamma-Gamma Coincidence Method to the Rapid Determination of Praseodymium. J. At. Energy Soc. Japan 5, No. 3, 218 (1963). 

Isolated tellurium clusters 48-50 (Tex n = 7-9) were produced in a supersonic molecular beam and their vacuum-UV-photoelectron spectra were recorded at a photon energy of hv = 8.3 eV by a photoionization-photoelectron-photoion triple coincidence method. The trimer and tetramer were obtained as stable species in the tellurium cluster beam, unlike sulfur and selenium. The spectra of the odd-membered tellurium clusters have a tendency to be split and broadened, in contrast to those of the seven-membered clusters. For the clusters with n > 5, the spectra of tellurium clusters are similar to those of selenium counterparts, which may suggest a resemblance to the geometric structures between small tellurium and selenium clusters (see Chapters 14.09 and 14.10) <2002MI337>. A similiar study has been conducted by Curtiss and co-workers on selenium clusters <1998CPL(287)282>. 

Delayed coincidence method used to determine radiative lifetime of F(2p 3p)... 

Source preparation techniques are the same as those explained in the 4n P-counting. Even in this 4n P-y coincidence method, the source preparation to minimize the self-absorption is important to reduce the correction terms and also to shorten the extrapolation range in the 4n p-y coincidence extrapolation technique. Hence the special treatments as explained in Table 5.4 are important in the course of source preparation. 

The second term of eq. (5.51) is a function of (1 -Ep), which will be reduced considerably in the use of a high efficiency detector, and excellent counting statistics are obtained in a short measuring time. This is another advantageous future use of the 4ti P y coincidence method. 

The dissociation of the 1,2,4,5-tetrazine dication has been investigated by the photoelectron, photoion coincidence method after photoexcitation in the far UV.450... 

The study of ion-molecule reactions using state-selected reagents has become a very exciting area of molecular dynamics. We have developed an experimental apparatus in Orsay which utilizes the properties of our tunable synchrotron radiation source at LURE to prepare ions in selected vibronic levels and then to study their reactions. The ions are state-selected using the TPEPICO (threshold-photoelectron/photoion coincidence) method [1]. 

Guss et al (1988) measured data at four wavelengths about the copper K edge, i.e. 1.2359 A, 1.3771 A, 1.3790 A and 1.5416 A. Of particular note in the data reduction was the need for an empirical method for coincidence losses to be used, as the analytical dead time correction for the area detector was unreliable at the upper end of the range of counting rates. As a result, merging f -factors within the data set at each wavelength were reduced by 20-60%, for the empirical versus the analytical coincidence method of data correction. 

Goincidence experiments have been common in nuclear physics since the 1930s.The widely used coincidence circuit of Rossi [9] allowed experimenters to determine, within the resolution time of the electronics of the day, whether two events were coincident in time. The early circuits were capable of submicrosecond resolution, but lacked the flexibility of today s equipment. The most important distinction between modem coincidence methods and those of the earlier days is the availability of semiconductor memories that allow one to now record precisely the time relations between all particles detected in an experiment. We shall see the importance of this in the evaluation of the statistical uncertainty of the results. 

The half-life of the 82-3-keV excited state as determined by two delayed coincidence methods and from the Mossbauer linewidth is = 3-8(3) ns... 

Lifetimes of more than 10" sec may be deter-mined by the delayed coincidence method (Bell I 1 2T ) if there is a preceding radiation. 

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