R. D. Head

First radiation hardness results of the TeraPixel Active Calorimeter (TPAC) sensor

The TeraPixel Active Calorimeter (TPAC) sensor is a novel Monolithic Active Pixel Sensors (MAPS) device developed for use as the active layers of a large area, digital electromagnetic calorimeter (DECAL) at a future e+e− collider. Further applications, which include the tracking and vertex systems for future lepton colliders and LHC upgrades have been proposed and it is therefore essential to characterise the behaviour of the sensor for these applications. We present the first studies of radiation hardness testing of the TPAC sensor. The performance of the sensor has been evaluated after exposures up to 5 Mrad of 50 keV x-rays. Under realistic ILC operating conditions a maximum decrease in the signal to noise ratio of 8% (15%) was observed after 200 krad (5 Mrad) which is already sufficient for proposed applications in future e+e− colliders.

Beam test results of FORTIS, a 4T MAPS sensor with a signal-to-noise ratio exceeding 100

We have tested the first 4T Monolithic Active Pixel Sensor (MAPS) for particle physics, FORTIS in a beam test. We have measured a signal-to-noise ratio of more than 100 for MIPs due to the excellent noise performance of the 4T architecture. Two versions of the sensor were tested; with and without deep P-well areas in-pixel. The deep P-well areas allow the incorporation of PMOS transistors inside the pixels without signal charge loss. The measured position resolutions were around 2 μm.