Method and apparatus for digitally based high speed x-ray spectrometer

A high speed, digitally based spectrometry method for analyzing an electronic signal containing step-like pulses, as from a preamplifier whose input is a photon or particle detector and wherein the amplitudes of the step-like pulses represent the energies of the photons or particles absorbed in the detector, which arrive at an average rate R, to estimate the amplitudes of at least some of said step-like pulses, the method comprising the steps of:

• digitizing the electronic signal with an analog to digital converter (ADC), operating at a sampling frequency S which is greater than R, to produce a digital representation of the electronic signal, the representation being referred to as the digitized input signal;
• providing digital combinatorial logic (FiPPI) clocked at frequency S or a multiple thereof;
• providing a programmable digital computing device (DSP) coupled to the digital combinatorial logic;
• applying a digital shaping filter to the digitized input signal, using the FiPPI;
• detecting the presence of the pulse signals in the digitized input signal, using the FiPPI;
• extracting estimates of amplitudes of the pulse signals from the output of the digital filter, using the FiPPI;
• transferring the estimates from the FiPPI to the DSP;
• and
• compensating the estimates for errors resulting from applying the digital filter to waveforms which are not ideal steps, using the DSP.

A high speed, digitally based spectrometry apparatus for analyzing an electronic signal containing step-like pulses, as from a preamplifier whose input is an photon or particle detector and wherein the amplitudes of the step-like pulses represent the energies of the photons or particles absorbed in the detector, which arrive at an average rate R, to estimates of the amplitudes of at least some of said step-like pulses, the apparatus comprising:

• an analog to digital converter (ADC), operating at a sampling frequency S which is greater than R, which digitizes the electronic signal to produce a digital representation of the electronic signal, the representation being referred to as the digitized input signal;
• digital combinatorial logic, referred to as the FiPPI, clocked at frequency S or a multiple thereof;
• and
• a programmable digital computing device (DSP) coupled to the FiPPI;
• wherein
• the FiPPI applies a digital shaping filter to the digitized input signal;
• the FiPPI detects the presence of the pulse signals in the digitized input signal;
• the FiPPI extracts estimates of the pulse signals' amplitudes from the output of the digital filter;
• the DSP captures the estimates from the FiPPI;
• and
• the DSP compensates the estimates for errors resulting from applying the digital filter to waveforms which are not ideal steps.