Measurement of the relative response of TowerJazz Mini-MALTA CMOS prototypes at Diamond Light Source

This paper outlines the results of investigations into the effects of radiation damage in the mini-MALTA prototype. Measurements were carried out at Diamond Light Source using a micro-focus X-ray beam, which scanned across the surface of the device in 2 $\mu \mathrm{m}$ steps. This allowed the in-pixel photon response to be measured directly with high statistics. Three pixel design variations were considered: one with the standard continuous ${\mathrm{n}}^{-}$ layer layout and front-end, and extra deep p-well and ${\mathrm{n}}^{-}$ gap designs with a modified front-end. Five chips were measured: one unirradiated, one neutron irradiated, and three proton irradiated.