Performance and uniformity of a kilo-pixel array of Ti/Au transition-edge sensor microcalorimeters

Uniform large transition-edge sensor (TES) arrays are fundamental for the next generation of X-ray space observatories. These arrays are required to achieve an energy resolution $Delta E$ < 3 eV full-width-half-maximum (FWHM) in the soft X-ray energy range. We are currently developing X-ray microcalorimeter arrays for use in future laboratory and space-based X-ray astrophysics experiments and ground-based spectrometers. In this contribution we report on the development and the characterization of a uniform 32$times$32 pixel array with 140$times$30 $mu$m$^2$ Ti/Au TESs with Au X-ray absorber. We report upon extensive measurements on 60 pixels in order to show the uniformity of our large TES array. The averaged critical temperature is $T_mathrm{c}$ = 89.5$pm$0.5 mK and the variation across the array ($sim$1 cm) is less than 1.5 mK. We found a large region of detectors bias points between 20% and 40% of the normal-state resistance where the energy resolution is constantly lower than 3 eV. In particular, results show a summed X-ray spectral resolution $Delta E_mathrm{FWHM}$ = 2.50$pm$0.04 eV at a photon energy of 5.9 keV, measured in a single-pixel mode using a frequency domain multiplexing (FDM) readout system developed at SRON/VTT at bias frequencies ranging from 1 to 5 MHz. Moreover we compare the logarithmic resistance sensitivity with respect to temperature and current ($alpha$ and $beta$ respectively) and their correlation with the detectors noise parameter $M$, showing an homogeneous behaviour for all the measured pixels in the array.