We attempt to compare the dust depth to measured molecular hydrogen columns. This shows that the gas to dust optical depth ratio towards sources in the Galactic Budge is not isotropic. While some depths can be explained with an empirical limb darkening model, many other dust depths in the sample clearly cannot. We find that while gas optical depths grow fairly consistent with broadband hydrogen equivalent densities, the dust optical depths do not. We discovered an instrumental feature affecting the Si K edge structure which we included in our analysis. We use HETG datasets that provide pile-up free spectra at Si K. We measure gas and dust optical depths at Si k towards 9 bright Low-Mass X-ray Binaries (LMXBs) in the Galactic Bulge with the highest precision so far. The Chandra High Energy Transmission Grating (HETG) Spectrometer provides a unique opportunity to measure X-ray absorption of interstellar dust as well as its compositions through X-ray edge absorption structure. The metal composition of the ISM enables us to study cooling and heating processes that dominate star formation rates in our Galaxy. Knowledge of the dust content in interstellar matter is of utmost importance in our understanding of the composition and evolution of the interstellar medium (ISM).
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