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Containing the oldest stars in the Galaxy, globular clusters toward the bulgecan be used to trace its dynamical and chemical evolution. In the bulgedirection, there are ~50 clusters, but only about 20% have been subject ofhigh-resolution spectroscopic investigations. So far, the sample observed athigh resolution spans a moderate-to-high metallicity regime. In this sample,however, very few are located in the innermost region ($R_{GC}\leq$1.5\,Kpc and$|l, b|\leq5^{\circ}$). To constrain the chemical evolution enrichment of theinnermost region of Galaxy, accurate abundances and abundance patterns of keyelements based on high-resolution spectroscopy are necessary. Here we presentthe results we obtained for Terzan 1, a metal-poor cluster located in theinnermost bulge region. Using the near-infrared spectrograph CRIRES at ESO/VLT,we obtained high-resolution (R$\approx$50,000) H-band spectra of 16 brightgiant stars in the innermost region ($r\leq 60"$) of Terzan1. Full spectralsynthesis techniques and equivalent width measurements of selected lines,isolated and free of significant blending and/or contamination by telluriclines, allowed accurate chemical abundances and radial velocities to bederived. Fifteen out of 16 observed stars are likely cluster members, with anaverage heliocentric radial velocity of +57$\pm$1.8\,km/s and mean ironabundance of [Fe/H]=--1.26$\pm$0.03\,dex. For these stars we measured some[$\alpha$/Fe] abundance ratios, finding average values of[O/Fe]=+0.39$\pm$0.02\,dex, [Mg/Fe]=+0.42$\pm$0.02\,dex,[Si/Fe]=+0.31$\pm$0.04\,dex, and [Ti/Fe]=+0.15$\pm$0.04\,dex The $\alpha$enhancement ($\approx +0.4$\,dex) found in the observed giant stars of Terzan1is consistent with previous measurements on other, more metal-rich bulgeclusters, which suggests a rapid chemical enrichment.

High-resolution CRIRES spectra of Terzan1: a metal-poor globular cluster toward the inner bulge