Abstract: A radiation analysis apparatus is provided with circuitry for correcting errors in a pulse-height distribution due to differential non-linearities of the analog-to-digital converter that is employed for digitising the detector signals. Correction is performed by multiplying counts by correction factors so as to form corrected counts constituting a corrected pulse-height spectrum. Correction factors are obtained by supplying to the analog-to-digital converter a known control-measurement detector signal having a known corresponding ideal pulse-height spectrum. Comparison of the pulse-height spectrum actually formed upon supplying the control-measurement detector signal with the ideal pulse-height spectrum provides correction factors that are stored in a memory.

Abstract: In a gas ionization x-ray detector pulse-amplitude shifts will adversely affect the accuracy of the analysis. At increasing count rates a space charge building up leads to a decrease of the impact ionization in the detector thereby causing the detected pulse amplitude to become lower. By means of addressing a pulse-shift correction random-access memory with digital signals representing detected pulse amplitudes count rates pertaining to high-energy parts and low-energy parts, respectively of a peak in a pulse-height distribution are generated. A difference of count rates for a high-energy part and for a low-energy part of the same peak in the pulse-height distribution indicates pulse-amplitude shift. On the basis of the differences of the high-energy count rate and the low-energy count rate a correction signal is produced for adjusting the amplification of the pulse-amplitudes. To obtain stable operation pulse-shift correction is activated only when the count rate exceeds a threshold value.

Abstract: Pulses generated by an x-ray gas ionisation detector have different temporal forms in dependence of the location in the detector where an x-ray photon interacts with a gas atom. The energy-resolution at count rates amounting to Mcts.sup.-1 of an x-ray analysis apparatus is improved by employing a resetable pulse-integrator. A resetable integrator is constructed by employing a dual gate field-effect transistor (FET) and a wide-band current feedback operational amplifier. Cross-talk due to parasitic capacitances is reduced by supplying a suitable DC voltage to one of the two gates of the dual gate FET. The gate control is made independent of the output of the integrator.

Abstract: In a spectrometer (1), a preparation (4) is irradiated with X-ray radiation. X-ray quanta emitted by the preparation (4) are converted after reflection from an analysis crystal (9) by a detection device (13) into pulse signals. In a pulse discrimination device (26), the pulse signals are discriminated and are recorded as single or multiple integrated pulse signals in a signal processing device (40) as numbers of pulse signals. After termination of the measurement, the numbers of pulse signals are read out from the signal processing device (40) and an analysis on the number takes place by means of a data processing device (51). For example, the total number of detected quanta of monochromatic radiation may be determined.

Abstract: A detection arrangement (1) for detecting variations in a signal has an input (5) to which is supplied a signal that is processed into a reference signal by a signal processing device (2) comprising a threshold circuit (3) followed by a signal hold circuit (6). The reference signal is formed at an output (12) of the signal hold circuit (6). The signal supplied to the input (5) of the detection arrangement and the reference signal formed at the output (12) of the signal hold circuit are supplied to a comparison circuit (9). The signal processing device ensures that the reference signal formed at the output of the signal hold circuit follows peaks and valleys of the signal except for a difference value, the reference signal assuming a threshold value when a peak or a valley is reached. If the signal varies within a range determined by the difference value around the threshold value, the signal hold circuit holds the threshold value.