Spectroscopy Study of Imaging Devices Based on Silicon Pixel Array Detector read out by VATAGP7 Chips V. Linhart a* , D. Burdette b , E. Chessi b , V. Cindro c , N.H. Clinthorne d , E. Cochran b , B. Grošičar c , K. Honscheid b , H. Kagan b , C. Lacasta a , G. Llosá a , M. Mikuž c,e , V. Stankova a , A. Studen c , P. Weilhammer b , and D. Žontar c a IFIC/CSIC-UVEG, Valencia, Spain b Ohio State University, Columbus, OH, USA c Jožef Stefan Institute, Ljubljana, Slovenia d University of Michigan, Ann Arbor, MI, USA e University of Ljubljana, Ljubljana, Slovenia E-mail: Vladimir.Linhart@ific.uv.es ABSTRACT: The work described in this text deals with spectroscopy and timing studies of a functional unit, the module, consisting of silicon Pixel Array Detector bonded on two read-out chips based on Application-Specific Integrated Circuit. We have performed spectroscopy and timing tests of the functional unit using laboratory gamma sources and the calibration facilities of the chips, as well. The performed tests have proven that the VATAGP7 chips have (i) non- linear calibration curves which can be approximated by power functions, (ii) capability to measure energy of electrons recoiled by photons with energy resolution better than 2 keV (exact range and resolution depend on experimental setup), (iii) six values of the charges of the internal calibration facility in our region of interest. These facts make from the VATAGP7 chips useful and precise tools for a variety of spectroscopic devices. Moreover, we have explored time walk of the module and peaking time of the spectroscopy signals provided by the chips. We have observed that (iv) the time walk is caused partly by the peaking time of the signals provided by the fast shaper of the chips and partly by the timing uncertainty related to varying position of photon interaction, (v) the peaking time of the spectroscopy signals provided by the chips is increasing with the increasing of their pulse heights. KEYWORDS: Spectroscopy; Silicon detectors; Compton Cameras, Small Animal PET, PET magnifying probes. * Corresponding author.