Book: X-rays in Theory and Experiment

Scope and purpose

"X-Rays in Theory and Experiment" presents a wide-ranging account of X-ray science as it stood in the mid-1930s, combining rigorous theoretical discussion with detailed experimental practice. Co-authored by Arthur Holly Compton and Samuel K. Allison, the book aims to provide both conceptual foundations and practical guidance, making it useful to physicists working on radiation phenomena, crystallographers, and engineers involved in X-ray instrumentation.

Foundations of X-ray theory

The authors develop the electromagnetic and quantum frameworks needed to understand X-ray emission and interaction. Treatment moves from classical electrodynamics to the quantum conception of photons, emphasizing how modern ideas reconcile wave and particle aspects. Central theoretical topics include the origin of continuous and characteristic spectra, the role of atomic electron shells in emission and absorption, and the quantum-mechanical explanation of scattering processes.

Compton scattering and its implications

A signature element of the book is the lucid exposition of the Compton effect and its significance for quantum theory. The scattering of X-rays by loosely bound electrons is derived and discussed with attention to kinematics and energy-momentum conservation, and the classic Compton wavelength shift is connected to experimental observables. The analysis highlights how measured shifts and angular distributions provide direct evidence for photon momentum and for the particle-like behavior of radiation.

Production and measurement of X-rays

Practical chapters describe X-ray generation, including the design and operation of tubes, control of accelerating potentials, and the distinction between continuous and characteristic radiation. Measurement techniques receive careful treatment: spectrometers, crystal diffraction methods, photographic and ionization detection, and early electronic counting techniques are explained with an emphasis on calibration, resolution, and sources of systematic error. Attention to experimental detail makes the text a working manual as well as a theoretical treatise.

Interaction with matter

The book treats absorption, attenuation, and scattering in matter, linking macroscopic attenuation coefficients to microscopic processes such as the photoelectric effect, coherent scattering, and incoherent (Compton) scattering. The dependence of absorption edges on atomic number and shell structure is explained, and the empirical regularities that underlie X-ray spectroscopy, such as Moseley-type relations, are discussed in relation to atomic models. Mathematical expressions for cross sections and mean free paths are given to connect theory with measurable quantities.

Experimental techniques and applications

Experimental practice is illustrated through examples in crystallography, spectroscopy, and radiographic imaging. Bragg diffraction and crystal spectrometers are treated as primary tools for wavelength determination and structure analysis, and experimental designs for scattering measurements are presented in detail. Practical applications ranging from mineralogy and chemical analysis to medical radiography are described, showing how X-ray methods serve both fundamental investigation and applied diagnostics.

Style, audience, and enduring value

Written with clarity and an eye for pedagogy, the text balances mathematical derivation with descriptive explanation and experimental nuance. It addresses graduate students and practicing scientists, requiring some familiarity with classical and quantum physics but offering enough experimental detail to guide laboratory work. As a historical snapshot, the book captures the consolidation of X-ray science in the era that followed the discovery of quantum phenomena and remains a valuable reference for understanding the experimental roots of modern X-ray techniques.