Response of a Large Sodium-Iodide Detector to High-Energy X-Rays

The response of a four-inch long by five-inch diameter sodium-iodide crystal to axially incident 0.01- to 8-Mev x-rays has been expressed as a 28 by 28 matrix. Measured pulse-height distributions were combined with Monte Carlo calculated distributions for the input data. The matrix was inverted on an automatic computer for ease of application to spectra. The mesh is uniform in the square root of energy, each interval including an entire photopeak. Such a coarse mesh makes the response matrix suitable for the unscrambling of continuous but not line spectra.