  We report on the design, commissioning, and initial measurements of a
Transition-edge Sensor (TES) x-ray spectrometer for the Electron Beam Ion Trap
(EBIT) at the National Institute of Standards and Technology (NIST). Over the
past few decades, the NIST EBIT has produced numerous studies of highly charged
ions in diverse fields such as atomic physics, plasma spectroscopy, and
laboratory astrophysics. The newly commissioned NIST EBIT TES Spectrometer
(NETS) improves the measurement capabilities of the EBIT through a combination
of high x-ray collection efficiency and resolving power. NETS utilizes 192
individual TES x-ray microcalorimeters (166/192 yield) to improve upon the
collection area by a factor of ~30 over the 4-pixel neutron transmutation doped
germanium-based microcalorimeter spectrometer previously used at the NIST EBIT.
The NETS microcalorimeters are optimized for the x-ray energies from roughly
500 eV to 8,000 eV and achieve an energy resolution of 3.7 eV to 5.0 eV over
this range, a more modest (<2X) improvement over the previous
microcalorimeters. Beyond this energy range NETS can operate with various
trade-offs, the most significant of which are reduced efficiency at lower
energies and being limited to a subset of the pixels at higher energies. As an
initial demonstration of the capabilities of NETS, we measured transitions in
He-like and H-like O, Ne, and Ar as well as Ni-like W. We detail the energy
calibration and data analysis techniques used to transform detector counts into
x-ray spectra, a process that will be the basis for analyzing future data.
