First spectral measurements of a distributed x-ray source with a Compton spectrometer

Our team at Los Alamos National Laboratory has performed many successful energy-spectra
measurements of both continuous and flash, intense radiographic sources with Compton
spectrometers. In this method, a collimated beam of x-rays incident on a convertor foil ejects
Compton electrons. A collimator may be inserted into the entrance of the spectrometer to
select the angular acceptance of the forward-scattered electrons, which then enter the
magnetic field region of the spectrometer. The position of the electrons at the magnet’s focal
plane is proportional to the square root of their momentum, allowing the x-ray spectrum to be
reconstructed. A Compton spectrometer with an energy range of <0.5 to 20 MeV recently
measured the x-ray energy spectrum produced by the Mercury pulsed-power machine at the
Naval Research Laboratory in its large-area diode configuration. These first-ever results from a
distributed x-ray source will be presented.