The Code SPECTRA

The code SPECTRA assumes that the flux is a piecewise-linear function of energy i.e., for any energy group j, one can write 

The flux f (E) from Eq. 14.44 is introduced into Eq. 14.41, and the integration is performed to give a matrix equation A = S4 , where A is an n X 1 vector whose components are the measured activities, S is an n X G matrix whose elements are integrals of the cross section of the form 

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The Peek-a-boo system is easy to use in the laboratory, and has a finite number of cards, each corresponding to a specific band interval of the spectrum. A card can have as many as 10,000 holes, and the locations of the holes correspond to serial numbers of the coded spectra. For example, the card for 6.5 has holes punched to correspond to the serial numbers of all the compounds displaying an absorption band at 6.5 fi. Each of the spectral characteristics to be coded is accounted for by similar cards. 

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