The Warm Electron Beam Ion Trap (WEBIT): An instrument for ground calibration of space-borne x-ray spectrometers

The warm electron beam ion trap (WEBIT) at Lawrence Livermore National Laboratory is being developed as a pre-launch, ground calibration source for space-borne, high-throughput, high-resolution x-ray spectrometers, such as the x-ray imaging and spectroscopy mission Resolve quantum calorimeter. Historically, calibration sources for calorimeter spectrometers have relied on characteristic line emission from x-ray tubes, fluorescing metals, and radioactive sources. The WEBIT, by contrast, relies on emission from x-ray transitions in highly charged ions, for example, hydrogen-like and helium-like ions, whose energies are well known and whose line shapes are relatively simple. The WEBIT can create astrophysically relevant ions whose x-ray emission falls in the 0.3-12 keV science bandpass of Resolve and has a portable design advantageous for a calibration source. The WEBIT will be used to help calibrate Resolve's instrumental line shape and gain scale as a function of various operational parameters during both detector subsystem level testing and instrumental level testing.