MEASUREMENT OF SPECTRA FROM X-RAY MACHINES

A transportable spectrometer and collimating system have been developed for the measurement of spectra from a variety of machines in different locations. The photon spectrum is required for the assessment of dose and radiographic effect in diagnostic radiography. The accuracy of calibration procedures using filtered X-ray beams is also improved if the spectrum produced is known precisely. The equipment can be set up and the measurement of a large range of operating conditions completed in about 8 hours. A computer program has been written to convert the observed pulse height distributions to photon spectra. The mean energy and width are given for a range of calibration spectra, and examples are shown of the spectra produced by the diagnostic machines. Some effects of tube current and potential waveform are discussed.