Abstract
The DBM (Discrimination Bias Modulation) method is one of electronic energy weighing techniques for carrying out the Spectrum-Dose conversion automatically. In the DBM method, the energy weighting is performed by passing the energetic pulses through the comparator (discriminator) of which the bias is modulated by a function wave.
In an original circuit, it was difficult to reduce the energy weighting error to less than ±5%, since the generated waveforms were not so accurate. Here, by using a Programmable Read Only Memory (PROM) for storing and for generating the waveforms, its error has been reduced to one tenth of the original one, and accurate operation of better than ±0.5% has been attained in the range from 100keV to 3MeV. In addition to the above, the reproducibility and the stability have been much improved, and the adjusting and testing processes of the function waveforms have been extremely simplified.
