New soft x-ray spectrometer on MST

Measurements of x-ray spectra in the MST are used to investigate the transport of energetic electrons and to estimate the effective charge $Z_{\mathrm{eff}}$. A new set of x-ray detectors is being implemented on the MST to detect x-rays in the energy range of $2$-$10\,\mathrm{keV}$. The new detectors are six Amptek XR-100CR modules with preamplifier and cooling. The detectors are connected to Cremat Gaussian shaping amplifiers with shaping times of either $500$ or $100\,\mathrm{ns}$. The shaping amplifier output is directly digitized at $60\,\mathrm{MHz}$, and the x-ray pulses are processed using a new code capable of correctly fitting multiple overlapping pulses. This configuration should allow a maximum count rate of $2$-$5\,\mathrm{MHz}$. The detectors can be placed in any of 17 ports covering $r/a$ values from 0.87 inboard to 0.84 outboard allowing measurements of inboard-outboard symmetry. The new detectors compliment the current system composed of 13 $\mathrm{CdZnTe}$ detectors detecting hard x-rays in the $10$-$150\,\mathrm{keV}$ energy range. The composite energy spectra of these x-ray diagnostics will be used with CQL3D Fokker-Planck modeling to constrain key parameters such as the electron radial diffusion coefficient and $Z_{\mathrm{eff}}$.