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An EBIT can selectively create, in principle, any charge state of every naturally occurring element, has good control on atomic collision processes, and can produce nearly ideal conditions for the analysis of highly ionized plasmas of astrophysical importance. A microcalorimeter enables the broadband detection of x-ray emission with high energy resolution and near-unity quantum efficiency in the energy range wherein many cosmic x-ray sources emit the bulk of their energy (0.2 keV–10 keV). The combination (EBIT+ microcalorimeter) provides a powerful tool for laboratory studies of the atomic/plasma processes underlying the energy release mechanisms in cosmic x-ray sources. We briefly describe some early experiments with a microcalorimeter built by the Smithsonian Astrophysical Observatory (SAO) and deployed on the NIST EBIT. We also present some very recent observations with a more advanced microcalorimeter built by SAO that can obtain an energy resolution of 4.5 eV. The higher spectral quality produced by the new system will be useful in laboratory measurements of interest in x-ray astronomy.

This paper contains a brief introduction to the main parameters of a micro-calorimeter designed to operate at the Shanghai electron beam ion trap. This is followed by short descriptions of some aspects of the calorimeter.

Measurements of broad band continua and line energies, shapes and relative intensities will allow estimates to be made of gas temperature, density and ionization state, elemental abundance, and gas velocity for objects such as supernova remnants, binary sources, and clusters of galaxies. Under favorable conditions, a redshift determination for extragalactic sources is possible. A wide variety of instrumentation to perform these measurements is currently available. A concentrating X-ray telescope with a proportional counter system at its focus offers very high throughput at the expense of resolution (E/ΔE ~ 1 to 5). At the other extreme, a free-standing, self-focusing array of Bragg crystals has low throughput but high resolution (E/ΔE ~ 103 or more). In between there are many possibilities to choose from. Very successful X-ray spectroscopic studies of cosmic X-ray sources have already been accomplished by the HEAO-1 and -2 programs. Those results allow future spectroscopy missions to be planned properly. Dispersive and non-dispersive instruments are described and complete, self-consistent calculations of their relative sensitivities for the detection of emission lines are presented.