Y. Bilevych

A UV sensitive integrated micromegas with timepix readout

This article presents a detector system consisting of three components, a CMOS imaging array, a gaseous-detector structure with a Micromegas layout, and a UV-photon sensitive CsI reflective photocathode. All three elements have been monolithically integrated using simple post-processing steps. The Micromegas structure and the CMOS imaging chip are not impacted by the CsI deposition. The detector operated reliably in He/isobutene mixtures and attained charge gains with single photons up to a level of 6x104. The Timepix CMOS array permitted high resolution imaging of single UV-photons. The system has an MTF50 of 0.4lp/pixel which corresponds to approximately 7lp/mm.

New results from GridPix detectors

GridPix detector prototypes have been made using a TimePix pixel chip and a PSI 46 pixel chip. A system of discharge protection has been successfully tested. GridPix detectors have been tested using cosmic rays, a 90Sr source and the T9 test beam facility at CERN. GridPix detectors perform well for 3D track reconstruction, dE/dx measurements and transition radiation detection.

InGrid: Pixelated Micromegas detectors for a Pixel-TPC

Within the LCTPC collaboration several possibilities to build a time projection chamber for a linear collider are studied. In all concepts, micro-pattern gaseous detectors (MPGD) are used as amplification structure. Compared to the traditional pad-based readouts used in most cases, a pixelated TPC is a new approach. Only pixel ASICs can reflect the high granularity of MPGDs from the readout side. The idea to combine these two technologies was already conceived ten years ago. Such devices, called InGrids, are produced in a photolithographic process, when a grid is post-processed on a Timepix

Charge protection characterisation and drift time resolution improvement for GridPix

A GridPix detector is a gaseous detector capable of detecting single primary electrons from ionising particles. Such a detector consists of a pixel chip as active anode covered with a thin layer of silicon rich silicon nitride (SiRN) for protection against discharges. A layer of 8 µm SiRN, and according recent tests even 4 µm, is sufficient to protect against discharges. The effect of the thickness of the SiRN layer on the operation of a detector has been determined.

Performance of a GridPix detector based on the Timepix3 chip

Abstract A GridPix readout for a TPC based on the Timepix3 chip is developed for future applications at a linear collider. The GridPix detector consists of a gaseous drift volume read out by a single Timepix3 chip with an integrated amplification grid. Its performance is studied in a test beam with 2.5 GeV electrons. The GridPix detector detects single ionization electrons with high efficiency. The Timepix3 chip allowed for high sample rates and time walk corrections. Diffusion is found to be the dominating error on the track position measurement both in the pixel plane and in the drift direction, and systematic distortions in the pixel plane are below 10 μ m. Using a truncated sum, an energy loss (dE/dx) resolution of 4.1% is found for an effective track length of 1 m.