Spectrum Subtraction Research Articles

Determination of chlorine and sodium in selenium by non-destructive neutron activation analysis

A non-destructive determination of Cl and Na traces in selenium by means of γ-scintillation spectrometry is described. The influence of these elements on the semiconductor properties of selenium is mentioned. The nuclear data of the matrix is discussed. The best activation and measurement conditions for the BER (Berlin Reactor), which allowed the determination of 0·01 ppm Na and 10 ppm Cl, are indicated. It was necessary to apply a method of spectrum subtraction to the determination of low Cl concentrations.

Angular distributions of neutrons elastically scattered from O 18

The angular distributions of neutrons elastically scattered from O 18 were measured for neutron energies between 405 and 2702 keV by the recoil-particle method. For these measurements, a proportional counter filled with carbon dioxide enriched to 97.2% in O 18 was irradiated with neutrons, and the recoil spectra were recorded by a 256-channel pulse-height analyser. Subtraction of the carbon recoil spectra yielded the O 18 spectra. The results were analysed in conjunction with the total neutron cross-section measurements of Vaughn et al., using one- and two-level nuclear dispersion theory. New states in O 19 have been located at excitation energies of 5.097, 6.13, and 6.20 MeV. Definite spin and parity assignments of 3 2− , 1 2− , and 5 2+ , have been made to the states at excitation energies of 4.587, 5.097, and 5.43 MeV respectively. In addition, probable spin and parity assignments of 3 2+ , 1 2− , and 7 2− , have been made to the states at excitation energies of 6.13, 6.20 and 6.271 MeV respectively. In the excitation energy region near 5.5. MeV, there is definite evidence for an additional level, for which a probable assignment of 1 2− has been made.

On the subtraction of gamma-ray spectra as a tool in radioactivation analysis

On the subtraction of gamma-ray spectra as a tool in radioactivation analysis

Spectroscopy from the Point of View of Communication Theory Part IV Automatic Recording of Infrared Spectra on Punched Cards

It is desirable to record infrared spectra point by point in digital form on punched cards in order to use automatic-machine methods of processing the data; for example, in calibration, conversion to absorption coefficient, comparison of spectra, subtraction of spectra of an identified constituent from that of an unknown mixture. Recording spectra in this way also allows the introduction of new methods suggested by communication theory of improving signal-to-noise ratio by smoothing noisy data with correlation functions. In applying these methods the computing machine can be considered as a nonlinear filter, part of the infrared equipment.The punched-card record is made by attaching to the output of the detector voltage amplifier a Digital Reader in parallel with the conventional graphic recorder. The Digital Reader converts the deflection voltage into a binary code represented by closure of circuits. These may be made to operate a Key Punch which punches into a single column of a standard card the record of the voltage in binary digital form. The data can then be processed by standard punched-card equipment.Examples of various kinds of spectra recorded in digital form on punched cards are presented, together with some examples of processed data.