High resolution gamma-ray spectroscopy: the first 85 years

Abstract

This opening review attempts to follow the main trends in crystal diffraction spectrometry of nuclear γ rays from its 1914 beginning in Rutherford’s laboratory to the ultra-high resolution instrumentation realized in the current generation of spectrometers at the Institute Laue Langeven (ILL). My perspective is that of an instrumentalist hoping to convey a sense of our intellectual debt to a number of predecessors, each of whom realized a certain elegance in making the tools that have enabled much good science, including that to which the remainder of this workshop is dedicated. This overview follows some of the main ideas along a trajectory toward higher resolution at higher energies, thereby enabling not only the disentangling of dense spectra, but also allowing detailed study of aspects of spectral profiles sensitive to excited state lifetimes and inter-atomic potentials. The parallel evolution toward increasing efficiency while preserving needed resolution is also an interesting story of artful compromise that should not be neglected. Finally, it is the robustness of the measurement chain connecting γ-ray wavelengths with optical wavelengths associated with the Rydberg constant that only recently has allowed γ-ray data to contribute to determination of particle masses and fundamental constants, as will be described in more detail in other papers from this workshop.

High-precision laser-assisted absolute determination of x-ray diffraction angles

“…Crystal spectrometers using curved [33][34][35][36][37] or flat crystals are still used for high-resolution measurements of x-ray transition energies. The Bragg angle θ is typically determined with fractional uncertainties θ /θ in the tens of ppm region relative to those of x-ray reference lines, e.g., K α transition lines of copper, molybdenum, and tungsten, 38 by fixing the direction of incoming x-rays by collimating slits, 39 which unfortunately also reduces the x-ray flux.…”

Aplicaciones de técnicas espectroscópicas para el análisis de suelos

“…Los cimientos de la espectrometría de rayos gama se dieron en 1914 con los trabajos de Rutherford y Andrade (Deslattes, 2000). Los rayos gama son emitidos de núcleos radioactivos en sus procesos de descomposición, un rayo gama tiene una energía definida y un núcleo radioactivo emite muchos rayos gama con diferente energía mientras que otros solo emiten un rayo gama con una energía.…”

Monte-Carlo simulations of the background of the coded-mask camera for X- and Gamma-rays on-board the Chinese–French GRB mission SVOM

“…4; the line characteristics in Fig. 4 are from [23,24,25]). The intensity of the Au fluorescence lines coming from the electronics is likely to be overestimated due to the crude modelling of the electronics in our simulations at the moment.…”

“…The numbers mentioned in parenthesis correspond to the relative intensities of the lines [23]. The line energies come from [24]. Note that the values mentioned in the Table are slightly different from those used in Geant4 [25].…”